/*******************************************************************************
 * Copyright (c) 2000, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.core;

import java.io.File;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;

import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IWorkspaceRoot;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.jdt.core.IAccessRule;
import org.eclipse.jdt.core.IClasspathAttribute;
import org.eclipse.jdt.core.IClasspathContainer;
import org.eclipse.jdt.core.IClasspathEntry;
import org.eclipse.jdt.core.IJavaModelStatus;
import org.eclipse.jdt.core.IJavaModelStatusConstants;
import org.eclipse.jdt.core.IJavaProject;
import org.eclipse.jdt.core.IPackageFragmentRoot;
import org.eclipse.jdt.core.JavaCore;
import org.eclipse.jdt.core.JavaModelException;
import org.eclipse.jdt.core.compiler.CharOperation;
import org.eclipse.jdt.core.compiler.IProblem;
import org.eclipse.jdt.internal.compiler.env.AccessRuleSet;
import org.eclipse.jdt.internal.compiler.env.AccessRule;
import org.eclipse.jdt.internal.compiler.impl.CompilerOptions;
import org.eclipse.jdt.internal.core.util.Messages;
import org.eclipse.jdt.internal.core.util.Util;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

/**
 * @see IClasspathEntry
 */
public class ClasspathEntry implements IClasspathEntry {

	public static final String TAG_CLASSPATH = "classpath"; //$NON-NLS-1$
	public static final String TAG_CLASSPATHENTRY = "classpathentry"; //$NON-NLS-1$
	public static final String TAG_OUTPUT = "output"; //$NON-NLS-1$
	public static final String TAG_KIND = "kind"; //$NON-NLS-1$
	public static final String TAG_PATH = "path"; //$NON-NLS-1$
	public static final String TAG_SOURCEPATH = "sourcepath"; //$NON-NLS-1$
	public static final String TAG_ROOTPATH = "rootpath"; //$NON-NLS-1$
	public static final String TAG_EXPORTED = "exported"; //$NON-NLS-1$
	public static final String TAG_INCLUDING = "including"; //$NON-NLS-1$
	public static final String TAG_EXCLUDING = "excluding"; //$NON-NLS-1$
	public static final String TAG_ATTRIBUTES = "attributes"; //$NON-NLS-1$
	public static final String TAG_ATTRIBUTE = "attribute"; //$NON-NLS-1$
	public static final String TAG_ATTRIBUTE_NAME = "name"; //$NON-NLS-1$
	public static final String TAG_ATTRIBUTE_VALUE = "value"; //$NON-NLS-1$
	public static final String TAG_COMBINE_ACCESS_RULES = "combineaccessrules"; //$NON-NLS-1$
	public static final String TAG_ACCESS_RULES = "accessrules"; //$NON-NLS-1$
	public static final String TAG_ACCESS_RULE = "accessrule"; //$NON-NLS-1$
	public static final String TAG_PATTERN = "pattern"; //$NON-NLS-1$
	public static final String TAG_ACCESSIBLE = "accessible"; //$NON-NLS-1$
	public static final String TAG_NON_ACCESSIBLE = "nonaccessible"; //$NON-NLS-1$
	public static final String TAG_DISCOURAGED = "discouraged"; //$NON-NLS-1$
	
	/**
	 * Describes the kind of classpath entry - one of 
	 * CPE_PROJECT, CPE_LIBRARY, CPE_SOURCE, CPE_VARIABLE or CPE_CONTAINER
	 */
	public int entryKind;

	/**
	 * Describes the kind of package fragment roots found on
	 * this classpath entry - either K_BINARY or K_SOURCE or
	 * K_OUTPUT.
	 */
	public int contentKind;

	/**
	 * The meaning of the path of a classpath entry depends on its entry kind:<ul>
	 *	<li>Source code in the current project (<code>CPE_SOURCE</code>) -  
	 *      The path associated with this entry is the absolute path to the root folder. </li>
	 *	<li>A binary library in the current project (<code>CPE_LIBRARY</code>) - the path
	 *		associated with this entry is the absolute path to the JAR (or root folder), and 
	 *		in case it refers to an external JAR, then there is no associated resource in 
	 *		the workbench.
	 *	<li>A required project (<code>CPE_PROJECT</code>) - the path of the entry denotes the
	 *		path to the corresponding project resource.</li>
	 *  <li>A variable entry (<code>CPE_VARIABLE</code>) - the first segment of the path 
	 *      is the name of a classpath variable. If this classpath variable
	 *		is bound to the path <it>P</it>, the path of the corresponding classpath entry
	 *		is computed by appending to <it>P</it> the segments of the returned
	 *		path without the variable.</li>
	 *  <li> A container entry (<code>CPE_CONTAINER</code>) - the first segment of the path is denoting
	 *     the unique container identifier (for which a <code>ClasspathContainerInitializer</code> could be
	 * 	registered), and the remaining segments are used as additional hints for resolving the container entry to
	 * 	an actual <code>IClasspathContainer</code>.</li>
	 */
	public IPath path;

	/**
	 * Patterns allowing to include/exclude portions of the resource tree denoted by this entry path.
	 */
	private IPath[] inclusionPatterns;
	private char[][] fullInclusionPatternChars;
	private IPath[] exclusionPatterns;
	private char[][] fullExclusionPatternChars;
	private final static char[][] UNINIT_PATTERNS = new char[][] { "Non-initialized yet".toCharArray() }; //$NON-NLS-1$
	
	private boolean combineAccessRules;
	
	private String rootID;
	private AccessRuleSet accessRuleSet;
	
	/*
	 * Default inclusion pattern set
	 */
	public final static IPath[] INCLUDE_ALL = {};
				
	/*
	 * Default exclusion pattern set
	 */
	public final static IPath[] EXCLUDE_NONE = {};
	
	/*
	 * Default extra attributes
	 */
	public final static IClasspathAttribute[] NO_EXTRA_ATTRIBUTES = {};
	
	/*
	 * Default access rules
	 */
	public final static IAccessRule[] NO_ACCESS_RULES = {};
				
	/**
	 * Describes the path to the source archive associated with this
	 * classpath entry, or <code>null</code> if this classpath entry has no
	 * source attachment.
	 * <p>
	 * Only library and variable classpath entries may have source attachments.
	 * For library classpath entries, the result path (if present) locates a source
	 * archive. For variable classpath entries, the result path (if present) has
	 * an analogous form and meaning as the variable path, namely the first segment 
	 * is the name of a classpath variable.
	 */
	public IPath sourceAttachmentPath;

	/**
	 * Describes the path within the source archive where package fragments
	 * are located. An empty path indicates that packages are located at
	 * the root of the source archive. Returns a non-<code>null</code> value
	 * if and only if <code>getSourceAttachmentPath</code> returns 
	 * a non-<code>null</code> value.
	 */
	public IPath sourceAttachmentRootPath;

	/**
	 * Specific output location (for this source entry)
	 */
	public IPath specificOutputLocation;
	
	/**
	 * A constant indicating an output location.
	 */
	public static final int K_OUTPUT = 10;

	/**
	 * The export flag
	 */
	public boolean isExported;
	
	/*
	 * The extra attributes
	 */
	private IClasspathAttribute[] extraAttributes;

	/**
	 * Creates a class path entry of the specified kind with the given path.
	 */
	public ClasspathEntry(
		int contentKind,
		int entryKind,
		IPath path,
		IPath[] inclusionPatterns,
		IPath[] exclusionPatterns,
		IPath sourceAttachmentPath,
		IPath sourceAttachmentRootPath,
		IPath specificOutputLocation,
		boolean isExported,
		IAccessRule[] accessRules,
		boolean combineAccessRules,
		IClasspathAttribute[] extraAttributes) {

		this.contentKind = contentKind;
		this.entryKind = entryKind;
		this.path = path;
		this.inclusionPatterns = inclusionPatterns;
		this.exclusionPatterns = exclusionPatterns;
		
		AccessRuleSet ruleSet = createAccessRuleSet(accessRules);
		if (ruleSet != null) {
			// compute message template
			ruleSet.messageTemplate = getMessageTemplate();
		}
		this.accessRuleSet = ruleSet;
		
		this.combineAccessRules = combineAccessRules;
		this.extraAttributes = extraAttributes;
		
	    if (inclusionPatterns != INCLUDE_ALL && inclusionPatterns.length > 0) {
			this.fullInclusionPatternChars = UNINIT_PATTERNS;
	    }
	    if (exclusionPatterns.length > 0) {
			this.fullExclusionPatternChars = UNINIT_PATTERNS;
	    }
		this.sourceAttachmentPath = sourceAttachmentPath;
		this.sourceAttachmentRootPath = sourceAttachmentRootPath;
		this.specificOutputLocation = specificOutputLocation;
		this.isExported = isExported;
	}
	
	private static AccessRuleSet createAccessRuleSet(IAccessRule[] accessRules) {
		int length = accessRules == null ? 0 : accessRules.length;
		if (length == 0) return null;
		AccessRule[] rules = new AccessRule[length];
		System.arraycopy(accessRules, 0, rules, 0, length);
		return new AccessRuleSet(rules);
	}
	
	public boolean combineAccessRules() {
		return this.combineAccessRules;
	}
	
	/**
	 * Used to perform export/restriction propagation across referring projects/containers
	 */
	public ClasspathEntry combineWith(ClasspathEntry referringEntry) {
		if (referringEntry == null) return this;
		if (referringEntry.isExported() || referringEntry.getAccessRuleSet() != null ) {
			boolean combine = this.entryKind == CPE_SOURCE || referringEntry.combineAccessRules();
			return new ClasspathEntry(
								this.getContentKind(), this.getEntryKind(), this.getPath(),
								this.inclusionPatterns, 
								this.exclusionPatterns, 
								this.getSourceAttachmentPath(), this.getSourceAttachmentRootPath(), this.getOutputLocation(), 
								referringEntry.isExported() || this.isExported, // duplicate container entry for tagging it as exported
								combine(referringEntry.getAccessRules(), getAccessRules(), combine),
								this.combineAccessRules,
								this.extraAttributes); 
		}
		// no need to clone
		return this;
	}

	private IAccessRule[] combine(IAccessRule[] referringRules, IAccessRule[] rules, boolean combine) {
		if (!combine) return rules;
		if (rules == null) return referringRules;
		
		// concat access rules
		int referringRulesLength = referringRules.length;
		int accessRulesLength = rules.length;
		int rulesLength = referringRulesLength + accessRulesLength;
		IAccessRule[] result = new IAccessRule[rulesLength];
		System.arraycopy(referringRules, 0, result, 0, referringRulesLength);
		System.arraycopy(rules, 0, result, referringRulesLength, accessRulesLength);
		
		return result;
	}

	private static IClasspathAttribute[] decodeExtraAttributes(Element element) {
		Node extra = element.getElementsByTagName(TAG_ATTRIBUTES).item(0);
		if (extra == null) return NO_EXTRA_ATTRIBUTES;
		NodeList attributes = element.getElementsByTagName(TAG_ATTRIBUTE);
		if (attributes == null) return NO_EXTRA_ATTRIBUTES;
		int length = attributes.getLength();
		if (length == 0) return NO_EXTRA_ATTRIBUTES;
		IClasspathAttribute[] result = new IClasspathAttribute[length];
		int index = 0;
		for (int i = 0; i < length; ++i) {
			Node node = attributes.item(i);
			if (node.getNodeType() == Node.ELEMENT_NODE) {
				Element attribute = (Element)node;
				String name = attribute.getAttribute(TAG_ATTRIBUTE_NAME);
				if (name == null) continue;
				String value = attribute.getAttribute(TAG_ATTRIBUTE_VALUE);
				if (value == null) continue;
				result[index++] = new ClasspathAttribute(name, value);
			}
		}
		if (index != length)
			System.arraycopy(result, 0, result = new IClasspathAttribute[index], 0, index);
		return result;
	}
	
	private static IAccessRule[] decodeAccessRules(Element element) {
		Node accessRules = element.getElementsByTagName(TAG_ACCESS_RULES).item(0);
		if (accessRules == null || accessRules.getNodeType() != Node.ELEMENT_NODE) return null;
		NodeList list = ((Element) accessRules).getElementsByTagName(TAG_ACCESS_RULE);
		int length = list.getLength();
		if (length == 0) return null;
		IAccessRule[] result = new IAccessRule[length];
		int index = 0;
		for (int i = 0; i < length; i++) {
			Node accessRule = list.item(i);
			if (accessRule == null || accessRule.getNodeType() != Node.ELEMENT_NODE) return null;
			Element elementAccessRule = (Element) accessRule;
			String pattern = elementAccessRule.getAttribute(TAG_PATTERN);
			if (pattern == null) continue;
			String tagKind =  elementAccessRule.getAttribute(TAG_KIND);
			int kind;
			if (TAG_ACCESSIBLE.equals(tagKind))
				kind = IAccessRule.K_ACCESSIBLE;
			else if (TAG_NON_ACCESSIBLE.equals(tagKind))
				kind = IAccessRule.K_NON_ACCESSIBLE;
			else if (TAG_DISCOURAGED.equals(tagKind))
				kind = IAccessRule.K_DISCOURAGED;
			else
				continue;
			result[index++] = new ClasspathAccessRule(new Path(pattern), kind);
		}
		if (index != length)
			System.arraycopy(result, 0, result = new IAccessRule[index], 0, index);
		return result;
	}
	
	/**
	 * Decode some element tag containing a sequence of patterns into IPath[]
	 */
	private static IPath[] decodePatterns(Element element, String tag) {
		String sequence = element.getAttribute(tag);
		if (!sequence.equals("")) { //$NON-NLS-1$ 
			char[][] patterns = CharOperation.splitOn('|', sequence.toCharArray());
			int patternCount;
			if ((patternCount  = patterns.length) > 0) {
				IPath[] paths = new IPath[patternCount];
				for (int j = 0; j < patterns.length; j++){
					paths[j] = new Path(new String(patterns[j]));
				}
				return paths;
			}
		}
		return null;
	}
	/*
	 * Returns a char based representation of the exclusions patterns full path.
	 */
	public char[][] fullExclusionPatternChars() {

		if (this.fullExclusionPatternChars == UNINIT_PATTERNS) {
			int length = this.exclusionPatterns.length;
			this.fullExclusionPatternChars = new char[length][];
			IPath prefixPath = this.path.removeTrailingSeparator();
			for (int i = 0; i < length; i++) {
				this.fullExclusionPatternChars[i] = 
					prefixPath.append(this.exclusionPatterns[i]).toString().toCharArray();
			}
		}
		return this.fullExclusionPatternChars;
	}
	
	/*
	 * Returns a char based representation of the exclusions patterns full path.
	 */
	public char[][] fullInclusionPatternChars() {

		if (this.fullInclusionPatternChars == UNINIT_PATTERNS) {
			int length = this.inclusionPatterns.length;
			this.fullInclusionPatternChars = new char[length][];
			IPath prefixPath = this.path.removeTrailingSeparator();
			for (int i = 0; i < length; i++) {
				this.fullInclusionPatternChars[i] = 
					prefixPath.append(this.inclusionPatterns[i]).toString().toCharArray();
			}
		}
		return this.fullInclusionPatternChars;
	}

	/**
	 * Returns the XML encoding of the class path.
	 */
	public void elementEncode(XMLWriter writer, IPath projectPath, boolean indent, boolean newLine) {
		HashMap parameters = new HashMap();
		
		parameters.put(TAG_KIND, ClasspathEntry.kindToString(this.entryKind));
		
		IPath xmlPath = this.path;
		if (this.entryKind != IClasspathEntry.CPE_VARIABLE && this.entryKind != IClasspathEntry.CPE_CONTAINER) {
			// translate to project relative from absolute (unless a device path)
			if (xmlPath.isAbsolute()) {
				if (projectPath != null && projectPath.isPrefixOf(xmlPath)) {
					if (xmlPath.segment(0).equals(projectPath.segment(0))) {
						xmlPath = xmlPath.removeFirstSegments(1);
						xmlPath = xmlPath.makeRelative();
					} else {
						xmlPath = xmlPath.makeAbsolute();
					}
				}
			}
		}
		parameters.put(TAG_PATH, String.valueOf(xmlPath));
		
		if (this.sourceAttachmentPath != null) {
			xmlPath = this.sourceAttachmentPath;
			// translate to project relative from absolute 
			if (this.entryKind != IClasspathEntry.CPE_VARIABLE && projectPath != null && projectPath.isPrefixOf(xmlPath)) {
				if (xmlPath.segment(0).equals(projectPath.segment(0))) {
					xmlPath = xmlPath.removeFirstSegments(1);
					xmlPath = xmlPath.makeRelative();
				}
			}
			parameters.put(TAG_SOURCEPATH, String.valueOf(xmlPath));
		}
		if (this.sourceAttachmentRootPath != null) {
			parameters.put(TAG_ROOTPATH, String.valueOf(this.sourceAttachmentRootPath));
		}
		if (this.isExported) {
			parameters.put(TAG_EXPORTED, "true");//$NON-NLS-1$
		}
		encodePatterns(this.inclusionPatterns, TAG_INCLUDING, parameters);
		encodePatterns(this.exclusionPatterns, TAG_EXCLUDING, parameters);
		if (this.entryKind == CPE_PROJECT && !this.combineAccessRules)
			parameters.put(TAG_COMBINE_ACCESS_RULES, "false"); //$NON-NLS-1$
		
		
		if (this.specificOutputLocation != null) {
			IPath outputLocation = this.specificOutputLocation.removeFirstSegments(1);
			outputLocation = outputLocation.makeRelative();
			parameters.put(TAG_OUTPUT, String.valueOf(outputLocation));
		}

		boolean hasExtraAttributes = this.extraAttributes != NO_EXTRA_ATTRIBUTES;
		boolean hasRestrictions = getAccessRuleSet() != null;
		writer.printTag(TAG_CLASSPATHENTRY, parameters, indent, newLine, !hasExtraAttributes && !hasRestrictions /*close tag if no extra attributes and no restriction*/);
		
		if (hasExtraAttributes)
			encodeExtraAttributes(writer, indent, newLine);
	
		if (hasRestrictions)
			encodeAccessRules(writer, indent, newLine);

		if (hasExtraAttributes || hasRestrictions)
			writer.endTag(TAG_CLASSPATHENTRY, indent);
	}
	
	private void encodeExtraAttributes(XMLWriter writer, boolean indent, boolean newLine) {
		writer.startTag(TAG_ATTRIBUTES, indent);
		for (int i = 0; i < this.extraAttributes.length; i++) {
			IClasspathAttribute attribute = this.extraAttributes[i];
			HashMap parameters = new HashMap();
	    	parameters.put(TAG_ATTRIBUTE_NAME, attribute.getName());
			parameters.put(TAG_ATTRIBUTE_VALUE, attribute.getValue());
			writer.printTag(TAG_ATTRIBUTE, parameters, indent, newLine, true);
		}
		writer.endTag(TAG_ATTRIBUTES, indent);
	}
	
	private void encodeAccessRules(XMLWriter writer, boolean indent, boolean newLine) {

		writer.startTag(TAG_ACCESS_RULES, indent);
		AccessRule[] rules = getAccessRuleSet().getAccessRules();
		for (int i = 0, length = rules.length; i < length; i++) {
			encodeAccessRule(rules[i], writer, indent, newLine);
		}
		writer.endTag(TAG_ACCESS_RULES, indent);
	}
	
	private void encodeAccessRule(AccessRule accessRule, XMLWriter writer, boolean indent, boolean newLine) {

		HashMap parameters = new HashMap();
		parameters.put(TAG_PATTERN, new String(accessRule.pattern));
		
		switch (accessRule.problemId) {
			case IProblem.ForbiddenReference:
				parameters.put(TAG_KIND, TAG_NON_ACCESSIBLE);
				break;
			case IProblem.DiscouragedReference:
				parameters.put(TAG_KIND, TAG_DISCOURAGED);
				break;
			default:
				parameters.put(TAG_KIND, TAG_ACCESSIBLE);
				break;
		}
		
		writer.printTag(TAG_ACCESS_RULE, parameters, indent, newLine, true);

	}
	
	public static IClasspathEntry elementDecode(Element element, IJavaProject project) {
	
		IPath projectPath = project.getProject().getFullPath();
		String kindAttr = element.getAttribute(TAG_KIND);
		String pathAttr = element.getAttribute(TAG_PATH);

		// ensure path is absolute
		IPath path = new Path(pathAttr); 		
		int kind = kindFromString(kindAttr);
		if (kind != IClasspathEntry.CPE_VARIABLE && kind != IClasspathEntry.CPE_CONTAINER && !path.isAbsolute()) {
			path = projectPath.append(path);
		}
		// source attachment info (optional)
		IPath sourceAttachmentPath = 
			element.hasAttribute(TAG_SOURCEPATH)	
			? new Path(element.getAttribute(TAG_SOURCEPATH))
			: null;
		if (kind != IClasspathEntry.CPE_VARIABLE && sourceAttachmentPath != null && !sourceAttachmentPath.isAbsolute()) {
			sourceAttachmentPath = projectPath.append(sourceAttachmentPath);
		}
		IPath sourceAttachmentRootPath = 
			element.hasAttribute(TAG_ROOTPATH)
			? new Path(element.getAttribute(TAG_ROOTPATH))
			: null;
		
		// exported flag (optional)
		boolean isExported = element.getAttribute(TAG_EXPORTED).equals("true"); //$NON-NLS-1$

		// inclusion patterns (optional)
		IPath[] inclusionPatterns = decodePatterns(element, TAG_INCLUDING);
		if (inclusionPatterns == null) inclusionPatterns = INCLUDE_ALL;
		
		// exclusion patterns (optional)
		IPath[] exclusionPatterns = decodePatterns(element, TAG_EXCLUDING);
		if (exclusionPatterns == null) exclusionPatterns = EXCLUDE_NONE;
		
		// access rules (optional)
		IAccessRule[] accessRules = decodeAccessRules(element);
		
		// backward compatibility
		if (accessRules == null) {
			accessRules = getAccessRules(inclusionPatterns, exclusionPatterns);
		}

		// combine access rules (optional)
		boolean combineAccessRestrictions = !element.getAttribute(TAG_COMBINE_ACCESS_RULES).equals("false"); //$NON-NLS-1$
		
		// extra attributes (optional)
		IClasspathAttribute[] extraAttributes = decodeExtraAttributes(element);
		
		// custom output location
		IPath outputLocation = element.hasAttribute(TAG_OUTPUT) ? projectPath.append(element.getAttribute(TAG_OUTPUT)) : null;
		
		// recreate the CP entry
		IClasspathEntry entry = null;
		switch (kind) {

			case IClasspathEntry.CPE_PROJECT :
				entry = JavaCore.newProjectEntry(
												path, 
												accessRules,
												combineAccessRestrictions,
												extraAttributes,
												isExported);
				break;				
			case IClasspathEntry.CPE_LIBRARY :
				entry = JavaCore.newLibraryEntry(
												path,
												sourceAttachmentPath,
												sourceAttachmentRootPath,
												accessRules,
												extraAttributes,
												isExported);
				break;
			case IClasspathEntry.CPE_SOURCE :
				// must be an entry in this project or specify another project
				String projSegment = path.segment(0);
				if (projSegment != null && projSegment.equals(project.getElementName())) { // this project
					return JavaCore.newSourceEntry(path, inclusionPatterns, exclusionPatterns, outputLocation, extraAttributes);
				} else { 
					if (path.segmentCount() == 1) {
						// another project
						entry = JavaCore.newProjectEntry(
												path, 
												accessRules,
												combineAccessRestrictions,
												extraAttributes,
												isExported);
					} else {
						// an invalid source folder
						return JavaCore.newSourceEntry(path, inclusionPatterns, exclusionPatterns, outputLocation, extraAttributes);
					}
				}
				break;
			case IClasspathEntry.CPE_VARIABLE :
				entry = JavaCore.newVariableEntry(
						path,
						sourceAttachmentPath,
						sourceAttachmentRootPath, 
						accessRules,
						extraAttributes,
						isExported);
				break;
			case IClasspathEntry.CPE_CONTAINER :
				entry = JavaCore.newContainerEntry(
						path,
						accessRules,
						extraAttributes,
						isExported);
				break;
			case ClasspathEntry.K_OUTPUT :
				if (!path.isAbsolute()) return null;
				return new ClasspathEntry(
						ClasspathEntry.K_OUTPUT,
						IClasspathEntry.CPE_LIBRARY,
						path,
						INCLUDE_ALL, 
						EXCLUDE_NONE, 
						null, // source attachment
						null, // source attachment root
						null, // custom output location
						false,
						null,
						false, // no accessible files to combine
						NO_EXTRA_ATTRIBUTES);
			default :
				throw new Assert.AssertionFailedException(Messages.bind(Messages.classpath_unknownKind, kindAttr)); 
		}
		return entry;
	}

	/**
	 * Encode some patterns into XML parameter tag
	 */
	private static void encodePatterns(IPath[] patterns, String tag, Map parameters) {
		if (patterns != null && patterns.length > 0) {
			StringBuffer rule = new StringBuffer(10);
			for (int i = 0, max = patterns.length; i < max; i++){
				if (i > 0) rule.append('|');
				rule.append(patterns[i]);
			}
			parameters.put(tag, String.valueOf(rule));
		}
	}

	/**
	 * Returns true if the given object is a classpath entry
	 * with equivalent attributes.
	 */
	public boolean equals(Object object) {
		if (this == object)
			return true;
		if (object instanceof ClasspathEntry) {
			ClasspathEntry otherEntry = (ClasspathEntry) object;

			if (this.contentKind != otherEntry.getContentKind())
				return false;

			if (this.entryKind != otherEntry.getEntryKind())
				return false;

			if (this.isExported != otherEntry.isExported())
				return false;

			if (!this.path.equals(otherEntry.getPath()))
				return false;

			IPath otherPath = otherEntry.getSourceAttachmentPath();
			if (this.sourceAttachmentPath == null) {
				if (otherPath != null)
					return false;
			} else {
				if (!this.sourceAttachmentPath.equals(otherPath))
					return false;
			}

			otherPath = otherEntry.getSourceAttachmentRootPath();
			if (this.sourceAttachmentRootPath == null) {
				if (otherPath != null)
					return false;
			} else {
				if (!this.sourceAttachmentRootPath.equals(otherPath))
					return false;
			}

			if (!equalPatterns(this.inclusionPatterns, otherEntry.getInclusionPatterns()))
				return false;
			if (!equalPatterns(this.exclusionPatterns, otherEntry.getExclusionPatterns()))
				return false;
			AccessRuleSet otherRuleSet = otherEntry.getAccessRuleSet();
			if (getAccessRuleSet() != null) {
				if (!getAccessRuleSet().equals(otherRuleSet))
					return false;
			} else if (otherRuleSet != null)
				return false;
			if (this.combineAccessRules != otherEntry.combineAccessRules())
				return false;
			otherPath = otherEntry.getOutputLocation();
			if (this.specificOutputLocation == null) {
				if (otherPath != null)
					return false;
			} else {
				if (!this.specificOutputLocation.equals(otherPath))
					return false;
			}
			if (!equalAttributes(this.extraAttributes, otherEntry.getExtraAttributes()))
				return false;
			return true;
		} else {
			return false;
		}
	}

	private static boolean equalAttributes(IClasspathAttribute[] firstAttributes, IClasspathAttribute[] secondAttributes) {
		if (firstAttributes != secondAttributes){
		    if (firstAttributes == null) return false;
			int length = firstAttributes.length;
			if (secondAttributes == null || secondAttributes.length != length) 
				return false;
			for (int i = 0; i < length; i++) {
				if (!firstAttributes[i].equals(secondAttributes[i]))
					return false;
			}
		}
		return true;
	}
	
	private static boolean equalPatterns(IPath[] firstPatterns, IPath[] secondPatterns) {
		if (firstPatterns != secondPatterns){
		    if (firstPatterns == null) return false;
			int length = firstPatterns.length;
			if (secondPatterns == null || secondPatterns.length != length) 
				return false;
			for (int i = 0; i < length; i++) {
				// compare toStrings instead of IPaths 
				// since IPath.equals is specified to ignore trailing separators
				if (!firstPatterns[i].toString().equals(secondPatterns[i].toString()))
					return false;
			}
		}
		return true;
	}
	
	/**
	 * @see IClasspathEntry#getAccessRules()
	 */
	public IAccessRule[] getAccessRules() {
		if (this.accessRuleSet == null) return NO_ACCESS_RULES;
		AccessRule[] rules = this.accessRuleSet.getAccessRules();
		int length = rules.length;
		if (length == 0) return NO_ACCESS_RULES;
		IAccessRule[] result = new IAccessRule[length];
		System.arraycopy(rules, 0, result, 0, length);
		return result;
	}
	
	public AccessRuleSet getAccessRuleSet() {
		return this.accessRuleSet;
	}

	/**
	 * @see IClasspathEntry
	 */
	public int getContentKind() {
		return this.contentKind;
	}

	/**
	 * @see IClasspathEntry
	 */
	public int getEntryKind() {
		return this.entryKind;
	}

	/**
	 * @see IClasspathEntry#getExclusionPatterns()
	 */
	public IPath[] getExclusionPatterns() {
		return this.exclusionPatterns;
	}
	
	public IClasspathAttribute[] getExtraAttributes() {
		return this.extraAttributes;
	}
	
	private String getMessageTemplate() {
		if (this.entryKind == CPE_PROJECT || this.entryKind == CPE_SOURCE) { // can be remote source entry when reconciling
			return Messages.bind(
				org.eclipse.jdt.internal.core.util.Messages.restrictedAccess_project,
				new String[] {"{0}", getPath().segment(0)});  //$NON-NLS-1$
		} else {
			IPath libPath = getPath();
			Object target = JavaModel.getTarget(ResourcesPlugin.getWorkspace().getRoot(), libPath, false);
			String pathString;
			if (target instanceof java.io.File)
				pathString = libPath.toOSString();
			else
				pathString = libPath.makeRelative().toString();
			return Messages.bind(
				org.eclipse.jdt.internal.core.util.Messages.restrictedAccess_library,
				new String[] {"{0}", pathString}); //$NON-NLS-1$ 
		}
	}

	/**
	 * @see IClasspathEntry#getExclusionPatterns()
	 */
	public IPath[] getInclusionPatterns() {
		return this.inclusionPatterns;
	}

	/**
	 * @see IClasspathEntry#getOutputLocation()
	 */
	public IPath getOutputLocation() {
		return this.specificOutputLocation;
	}

	/**
	 * @see IClasspathEntry
	 */
	public IPath getPath() {
		return this.path;
	}
	
	/**
	 * @see IClasspathEntry
	 */
	public IPath getSourceAttachmentPath() {
		return this.sourceAttachmentPath;
	}

	/**
	 * @see IClasspathEntry
	 */
	public IPath getSourceAttachmentRootPath() {
		return this.sourceAttachmentRootPath;
	}

	/**
	 * Returns the hash code for this classpath entry
	 */
	public int hashCode() {
		return this.path.hashCode();
	}

	/**
	 * @see IClasspathEntry#isExported()
	 */
	public boolean isExported() {
		return this.isExported;
	}

	/**
	 * Returns the kind of a <code>PackageFragmentRoot</code> from its <code>String</code> form.
	 */
	static int kindFromString(String kindStr) {

		if (kindStr.equalsIgnoreCase("prj")) //$NON-NLS-1$
			return IClasspathEntry.CPE_PROJECT;
		if (kindStr.equalsIgnoreCase("var")) //$NON-NLS-1$
			return IClasspathEntry.CPE_VARIABLE;
		if (kindStr.equalsIgnoreCase("con")) //$NON-NLS-1$
			return IClasspathEntry.CPE_CONTAINER;
		if (kindStr.equalsIgnoreCase("src")) //$NON-NLS-1$
			return IClasspathEntry.CPE_SOURCE;
		if (kindStr.equalsIgnoreCase("lib")) //$NON-NLS-1$
			return IClasspathEntry.CPE_LIBRARY;
		if (kindStr.equalsIgnoreCase("output")) //$NON-NLS-1$
			return ClasspathEntry.K_OUTPUT;
		return -1;
	}

	/**
	 * Returns a <code>String</code> for the kind of a class path entry.
	 */
	static String kindToString(int kind) {

		switch (kind) {
			case IClasspathEntry.CPE_PROJECT :
				return "src"; // backward compatibility //$NON-NLS-1$
			case IClasspathEntry.CPE_SOURCE :
				return "src"; //$NON-NLS-1$
			case IClasspathEntry.CPE_LIBRARY :
				return "lib"; //$NON-NLS-1$
			case IClasspathEntry.CPE_VARIABLE :
				return "var"; //$NON-NLS-1$
			case IClasspathEntry.CPE_CONTAINER :
				return "con"; //$NON-NLS-1$
			case ClasspathEntry.K_OUTPUT :
				return "output"; //$NON-NLS-1$
			default :
				return "unknown"; //$NON-NLS-1$
		}
	}

	public static IAccessRule[] getAccessRules(IPath[] accessibleFiles, IPath[] nonAccessibleFiles) {
		int accessibleFilesLength = accessibleFiles == null ? 0 : accessibleFiles.length;
		int nonAccessibleFilesLength = nonAccessibleFiles == null ? 0 : nonAccessibleFiles.length;
		int length = accessibleFilesLength + nonAccessibleFilesLength;
		if (length == 0) return null;
		IAccessRule[] accessRules = new IAccessRule[length];
		for (int i = 0; i < accessibleFilesLength; i++) {
			accessRules[i] = JavaCore.newAccessRule(accessibleFiles[i], IAccessRule.K_ACCESSIBLE);
		}
		for (int i = 0; i < nonAccessibleFilesLength; i++) {
			accessRules[accessibleFilesLength + i] = JavaCore.newAccessRule(nonAccessibleFiles[i], IAccessRule.K_NON_ACCESSIBLE);
		}
		return accessRules;
	}
	
	/**
	 * Returns a printable representation of this classpath entry.
	 */
	public String toString() {
		StringBuffer buffer = new StringBuffer();
		buffer.append(getPath().toString());
		buffer.append('[');
		switch (getEntryKind()) {
			case IClasspathEntry.CPE_LIBRARY :
				buffer.append("CPE_LIBRARY"); //$NON-NLS-1$
				break;
			case IClasspathEntry.CPE_PROJECT :
				buffer.append("CPE_PROJECT"); //$NON-NLS-1$
				break;
			case IClasspathEntry.CPE_SOURCE :
				buffer.append("CPE_SOURCE"); //$NON-NLS-1$
				break;
			case IClasspathEntry.CPE_VARIABLE :
				buffer.append("CPE_VARIABLE"); //$NON-NLS-1$
				break;
			case IClasspathEntry.CPE_CONTAINER :
				buffer.append("CPE_CONTAINER"); //$NON-NLS-1$
				break;
		}
		buffer.append("]["); //$NON-NLS-1$
		switch (getContentKind()) {
			case IPackageFragmentRoot.K_BINARY :
				buffer.append("K_BINARY"); //$NON-NLS-1$
				break;
			case IPackageFragmentRoot.K_SOURCE :
				buffer.append("K_SOURCE"); //$NON-NLS-1$
				break;
			case ClasspathEntry.K_OUTPUT :
				buffer.append("K_OUTPUT"); //$NON-NLS-1$
				break;
		}
		buffer.append(']');
		if (getSourceAttachmentPath() != null) {
			buffer.append("[sourcePath:"); //$NON-NLS-1$
			buffer.append(getSourceAttachmentPath());
			buffer.append(']');
		}
		if (getSourceAttachmentRootPath() != null) {
			buffer.append("[rootPath:"); //$NON-NLS-1$
			buffer.append(getSourceAttachmentRootPath());
			buffer.append(']');
		}
		buffer.append("[isExported:"); //$NON-NLS-1$
		buffer.append(this.isExported);
		buffer.append(']');
		IPath[] patterns = this.inclusionPatterns;
		int length;
		if ((length = patterns == null ? 0 : patterns.length) > 0) {
			buffer.append("[including:"); //$NON-NLS-1$
			for (int i = 0; i < length; i++) {
				buffer.append(patterns[i]);
				if (i != length-1) {
					buffer.append('|');
				}
			}
			buffer.append(']');
		}
		patterns = this.exclusionPatterns;
		if ((length = patterns == null ? 0 : patterns.length) > 0) {
			buffer.append("[excluding:"); //$NON-NLS-1$
			for (int i = 0; i < length; i++) {
				buffer.append(patterns[i]);
				if (i != length-1) {
					buffer.append('|');
				}
			}
			buffer.append(']');
		}
		if (this.accessRuleSet != null) {
			buffer.append('[');
			buffer.append(this.accessRuleSet.toString(false/*on one line*/));
			buffer.append(']');
		}
		if (this.entryKind == CPE_PROJECT) {
			buffer.append("[combine access rules:"); //$NON-NLS-1$
			buffer.append(this.combineAccessRules);
			buffer.append(']');
		}
		if (getOutputLocation() != null) {
			buffer.append("[output:"); //$NON-NLS-1$
			buffer.append(getOutputLocation());
			buffer.append(']');
		}
		if ((length = this.extraAttributes == null ? 0 : this.extraAttributes.length) > 0) {
			buffer.append("[attributes:"); //$NON-NLS-1$
			for (int i = 0; i < length; i++) {
				buffer.append(this.extraAttributes[i]);
				if (i != length-1) {
					buffer.append(',');
				}
			}
			buffer.append(']');
		}
		return buffer.toString();
	}
	
	/**
	 * Answers an ID which is used to distinguish entries during package
	 * fragment root computations
	 */
	public String rootID(){

		if (this.rootID == null) {
			switch(this.entryKind){
				case IClasspathEntry.CPE_LIBRARY :
					this.rootID = "[LIB]"+this.path;  //$NON-NLS-1$
					break;
				case IClasspathEntry.CPE_PROJECT :
					this.rootID = "[PRJ]"+this.path;  //$NON-NLS-1$
					break;
				case IClasspathEntry.CPE_SOURCE :
					this.rootID = "[SRC]"+this.path;  //$NON-NLS-1$
					break;
				case IClasspathEntry.CPE_VARIABLE :
					this.rootID = "[VAR]"+this.path;  //$NON-NLS-1$
					break;
				case IClasspathEntry.CPE_CONTAINER :
					this.rootID = "[CON]"+this.path;  //$NON-NLS-1$
					break;
				default :
					this.rootID = "";  //$NON-NLS-1$
					break;
			}
		}
		return this.rootID;
	}
	
	/**
	 * @see IClasspathEntry
	 * @deprecated
	 */
	public IClasspathEntry getResolvedEntry() {
	
		return JavaCore.getResolvedClasspathEntry(this);
	}
	
	/**
	 * Validate a given classpath and output location for a project, using the following rules:
	 * <ul>
	 *   <li> Classpath entries cannot collide with each other; that is, all entry paths must be unique.
	 *   <li> The project output location path cannot be null, must be absolute and located inside the project.
	 *   <li> Specific output locations (specified on source entries) can be null, if not they must be located inside the project,
	 *   <li> A project entry cannot refer to itself directly (that is, a project cannot prerequisite itself).
     *   <li> Classpath entries or output locations cannot coincidate or be nested in each other, except for the following scenarii listed below:
	 *      <ul><li> A source folder can coincidate with its own output location, in which case this output can then contain library archives. 
	 *                     However, a specific output location cannot coincidate with any library or a distinct source folder than the one referring to it. </li> 
	 *              <li> A source/library folder can be nested in any source folder as long as the nested folder is excluded from the enclosing one. </li>
	 * 			<li> An output location can be nested in a source folder, if the source folder coincidates with the project itself, or if the output
	 * 					location is excluded from the source folder. </li>
	 *      </ul>
	 * </ul>
	 * 
	 *  Note that the classpath entries are not validated automatically. Only bound variables or containers are considered 
	 *  in the checking process (this allows to perform a consistency check on a classpath which has references to
	 *  yet non existing projects, folders, ...).
	 *  <p>
	 *  This validation is intended to anticipate classpath issues prior to assigning it to a project. In particular, it will automatically
	 *  be performed during the classpath setting operation (if validation fails, the classpath setting will not complete).
	 *  <p>
	 * @param javaProject the given java project
	 * @param rawClasspath a given classpath
	 * @param projectOutputLocation a given output location
	 * @return a status object with code <code>IStatus.OK</code> if
	 *		the given classpath and output location are compatible, otherwise a status 
	 *		object indicating what is wrong with the classpath or output location
	 */
	public static IJavaModelStatus validateClasspath(IJavaProject javaProject, IClasspathEntry[] rawClasspath, IPath projectOutputLocation) {
	
		IProject project = javaProject.getProject();
		IPath projectPath= project.getFullPath();
		String projectName = javaProject.getElementName();
	
		/* validate output location */
		if (projectOutputLocation == null) {
			return new JavaModelStatus(IJavaModelStatusConstants.NULL_PATH);
		}
		if (projectOutputLocation.isAbsolute()) {
			if (!projectPath.isPrefixOf(projectOutputLocation)) {
				return new JavaModelStatus(IJavaModelStatusConstants.PATH_OUTSIDE_PROJECT, javaProject, projectOutputLocation.toString());
			}
		} else {
			return new JavaModelStatus(IJavaModelStatusConstants.RELATIVE_PATH, projectOutputLocation);
		}
	
		boolean hasSource = false;
		boolean hasLibFolder = false;
	

		// tolerate null path, it will be reset to default
		if (rawClasspath == null) 
			return JavaModelStatus.VERIFIED_OK;
		
		// retrieve resolved classpath
		IClasspathEntry[] classpath; 
		try {
			classpath = ((JavaProject)javaProject).getResolvedClasspath(rawClasspath, null /*output*/, true/*ignore pb*/, false/*no marker*/, null /*no reverse map*/);
		} catch(JavaModelException e){
			return e.getJavaModelStatus();
		}
		int length = classpath.length; 

		int outputCount = 1;
		IPath[] outputLocations	= new IPath[length+1];
		boolean[] allowNestingInOutputLocations = new boolean[length+1];
		outputLocations[0] = projectOutputLocation;
		
		// retrieve and check output locations
		IPath potentialNestedOutput = null; // for error reporting purpose
		int sourceEntryCount = 0;
		boolean disableExclusionPatterns = JavaCore.DISABLED.equals(javaProject.getOption(JavaCore.CORE_ENABLE_CLASSPATH_EXCLUSION_PATTERNS, true));
		boolean disableCustomOutputLocations = JavaCore.DISABLED.equals(javaProject.getOption(JavaCore.CORE_ENABLE_CLASSPATH_MULTIPLE_OUTPUT_LOCATIONS, true));
		
		for (int i = 0 ; i < length; i++) {
			IClasspathEntry resolvedEntry = classpath[i];
			if (disableExclusionPatterns &&
			        ((resolvedEntry.getInclusionPatterns() != null && resolvedEntry.getInclusionPatterns().length > 0) 
			        || (resolvedEntry.getExclusionPatterns() != null && resolvedEntry.getExclusionPatterns().length > 0))) {
				return new JavaModelStatus(IJavaModelStatusConstants.DISABLED_CP_EXCLUSION_PATTERNS, javaProject, resolvedEntry.getPath());
			}
			switch(resolvedEntry.getEntryKind()){
				case IClasspathEntry.CPE_SOURCE :
					sourceEntryCount++;

					IPath customOutput; 
					if ((customOutput = resolvedEntry.getOutputLocation()) != null) {

						if (disableCustomOutputLocations) {
							return new JavaModelStatus(IJavaModelStatusConstants.DISABLED_CP_MULTIPLE_OUTPUT_LOCATIONS, javaProject, resolvedEntry.getPath());
						}
						// ensure custom output is in project
						if (customOutput.isAbsolute()) {
							if (!javaProject.getPath().isPrefixOf(customOutput)) {
								return new JavaModelStatus(IJavaModelStatusConstants.PATH_OUTSIDE_PROJECT, javaProject, customOutput.toString());
							}
						} else {
							return new JavaModelStatus(IJavaModelStatusConstants.RELATIVE_PATH, customOutput);
						}
						
						// ensure custom output doesn't conflict with other outputs
						// check exact match
						if (Util.indexOfMatchingPath(customOutput, outputLocations, outputCount) != -1) {
							continue; // already found
						}
						// accumulate all outputs, will check nesting once all available (to handle ordering issues)
						outputLocations[outputCount++] = customOutput;
					}
			}
		}
		// check nesting across output locations
		for (int i = 1 /*no check for default output*/ ; i < outputCount; i++) {
		    IPath customOutput = outputLocations[i];
		    int index;
			// check nesting
			if ((index = Util.indexOfEnclosingPath(customOutput, outputLocations, outputCount)) != -1 && index != i) {
				if (index == 0) {
					// custom output is nested in project's output: need to check if all source entries have a custom
					// output before complaining
					if (potentialNestedOutput == null) potentialNestedOutput = customOutput;
				} else {
					return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_cannotNestOutputInOutput, new String[] {customOutput.makeRelative().toString(), outputLocations[index].makeRelative().toString()})); 
				}
			}
		}	
		// allow custom output nesting in project's output if all source entries have a custom output
		if (sourceEntryCount <= outputCount-1) {
		    allowNestingInOutputLocations[0] = true;
		} else if (potentialNestedOutput != null) {
			return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_cannotNestOutputInOutput, new String[] {potentialNestedOutput.makeRelative().toString(), outputLocations[0].makeRelative().toString()})); 
		}

		for (int i = 0 ; i < length; i++) {
			IClasspathEntry resolvedEntry = classpath[i];
			IPath path = resolvedEntry.getPath();
			int index;
			switch(resolvedEntry.getEntryKind()){
				
				case IClasspathEntry.CPE_SOURCE :
					hasSource = true;
					if ((index = Util.indexOfMatchingPath(path, outputLocations, outputCount)) != -1){
						allowNestingInOutputLocations[index] = true;
					}
					break;

				case IClasspathEntry.CPE_LIBRARY:
					hasLibFolder |= !org.eclipse.jdt.internal.compiler.util.Util.isArchiveFileName(path.lastSegment());
					if ((index = Util.indexOfMatchingPath(path, outputLocations, outputCount)) != -1){
						allowNestingInOutputLocations[index] = true;
					}
					break;
			}
		}
		if (!hasSource && !hasLibFolder) { // if no source and no lib folder, then allowed
			for (int i = 0; i < outputCount; i++) allowNestingInOutputLocations[i] = true;
		}
		
		HashSet pathes = new HashSet(length);
		
		// check all entries
		for (int i = 0 ; i < length; i++) {
			IClasspathEntry entry = classpath[i];
			if (entry == null) continue;
			IPath entryPath = entry.getPath();
			int kind = entry.getEntryKind();
			
			// Build some common strings for status message
			boolean isProjectRelative = projectName.equals(entryPath.segment(0));
			String entryPathMsg = isProjectRelative ? entryPath.removeFirstSegments(1).toString() : entryPath.makeRelative().toString();
	
			// complain if duplicate path
			if (!pathes.add(entryPath)){
				return new JavaModelStatus(IJavaModelStatusConstants.NAME_COLLISION, Messages.bind(Messages.classpath_duplicateEntryPath, new String[] {entryPathMsg, projectName})); 
			}
			// no further check if entry coincidates with project or output location
			if (entryPath.equals(projectPath)){
				// complain if self-referring project entry
				if (kind == IClasspathEntry.CPE_PROJECT){
					return new JavaModelStatus(IJavaModelStatusConstants.INVALID_PATH, Messages.bind(Messages.classpath_cannotReferToItself, new String[] {entryPath.makeRelative().toString()}));
				}
				// tolerate nesting output in src if src==prj
				continue;
			}
	
			// allow nesting source entries in each other as long as the outer entry excludes the inner one
			if (kind == IClasspathEntry.CPE_SOURCE 
					|| (kind == IClasspathEntry.CPE_LIBRARY && !org.eclipse.jdt.internal.compiler.util.Util.isArchiveFileName(entryPath.lastSegment()))){
				for (int j = 0; j < classpath.length; j++){
					IClasspathEntry otherEntry = classpath[j];
					if (otherEntry == null) continue;
					int otherKind = otherEntry.getEntryKind();
					IPath otherPath = otherEntry.getPath();
					if (entry != otherEntry 
						&& (otherKind == IClasspathEntry.CPE_SOURCE 
								|| (otherKind == IClasspathEntry.CPE_LIBRARY 
										&& !org.eclipse.jdt.internal.compiler.util.Util.isArchiveFileName(otherPath.lastSegment())))){
						char[][] inclusionPatterns, exclusionPatterns;
						if (otherPath.isPrefixOf(entryPath) 
								&& !otherPath.equals(entryPath)
								&& !Util.isExcluded(entryPath.append("*"), inclusionPatterns = ((ClasspathEntry)otherEntry).fullInclusionPatternChars(), exclusionPatterns = ((ClasspathEntry)otherEntry).fullExclusionPatternChars(), false)) { //$NON-NLS-1$
							String exclusionPattern = entryPath.removeFirstSegments(otherPath.segmentCount()).segment(0);
							if (Util.isExcluded(entryPath, inclusionPatterns, exclusionPatterns, false)) {
								return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_mustEndWithSlash, new String[] {exclusionPattern, entryPath.makeRelative().toString()})); 
							} else {
								if (otherKind == IClasspathEntry.CPE_SOURCE) {
									exclusionPattern += '/';
									return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_cannotNestEntryInEntry, new String[] {entryPath.makeRelative().toString(), otherEntry.getPath().makeRelative().toString(), exclusionPattern})); 
								} else {
									return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_cannotNestEntryInLibrary, new String[] {entryPath.makeRelative().toString(), otherEntry.getPath().makeRelative().toString()})); 
								}
							}
						}
					}
				}
			}
			
			// prevent nesting output location inside entry unless enclosing is a source entry which explicitly exclude the output location
		    char[][] inclusionPatterns = ((ClasspathEntry)entry).fullInclusionPatternChars();
		    char[][] exclusionPatterns = ((ClasspathEntry)entry).fullExclusionPatternChars();
		    for (int j = 0; j < outputCount; j++){
		        IPath currentOutput = outputLocations[j];
    			if (entryPath.equals(currentOutput)) continue;
				if (entryPath.isPrefixOf(currentOutput)) {
				    if (kind != IClasspathEntry.CPE_SOURCE || !Util.isExcluded(currentOutput, inclusionPatterns, exclusionPatterns, true)) {
						return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_cannotNestOutputInEntry, new String[] {currentOutput.makeRelative().toString(), entryPath.makeRelative().toString()})); 
				    }
				}
		    }

		    // prevent nesting entry inside output location - when distinct from project or a source folder
		    for (int j = 0; j < outputCount; j++){
		        if (allowNestingInOutputLocations[j]) continue;
		        IPath currentOutput = outputLocations[j];
				if (currentOutput.isPrefixOf(entryPath)) {
					return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_cannotNestEntryInOutput, new String[] {entryPath.makeRelative().toString(), currentOutput.makeRelative().toString()})); 
				}
		    }			
		}
		// ensure that no specific output is coincidating with another source folder (only allowed if matching current source folder)
		// 36465 - for 2.0 backward compatibility, only check specific output locations (the default can still coincidate)
		// perform one separate iteration so as to not take precedence over previously checked scenarii (in particular should
		// diagnose nesting source folder issue before this one, for example, [src]"Project/", [src]"Project/source/" and output="Project/" should
		// first complain about missing exclusion pattern
		for (int i = 0 ; i < length; i++) {
			IClasspathEntry entry = classpath[i];
			if (entry == null) continue;
			IPath entryPath = entry.getPath();
			int kind = entry.getEntryKind();

			// Build some common strings for status message
			boolean isProjectRelative = projectName.equals(entryPath.segment(0));
			String entryPathMsg = isProjectRelative ? entryPath.removeFirstSegments(1).toString() : entryPath.makeRelative().toString();
	
			if (kind == IClasspathEntry.CPE_SOURCE) {
				IPath output = entry.getOutputLocation();
				if (output == null) continue; // 36465 - for 2.0 backward compatibility, only check specific output locations (the default can still coincidate)
				// if (output == null) output = projectOutputLocation; // if no specific output, still need to check using default output (this line would check default output)
				for (int j = 0; j < length; j++) {
					IClasspathEntry otherEntry = classpath[j];
					if (otherEntry == entry) continue;

					// Build some common strings for status message
					boolean opStartsWithProject = projectName.equals(otherEntry.getPath().segment(0));
					String otherPathMsg = opStartsWithProject ? otherEntry.getPath().removeFirstSegments(1).toString() : otherEntry.getPath().makeRelative().toString();
	
					switch (otherEntry.getEntryKind()) {
						case IClasspathEntry.CPE_SOURCE :
							if (otherEntry.getPath().equals(output)) {
								return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_cannotUseDistinctSourceFolderAsOutput, new String[] {entryPathMsg, otherPathMsg, projectName})); 
							}
							break;
						case IClasspathEntry.CPE_LIBRARY :
							if (otherEntry.getPath().equals(output)) {
								return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_cannotUseLibraryAsOutput, new String[] {entryPathMsg, otherPathMsg, projectName})); 
							}
					}
				}
			}			
		}
		return JavaModelStatus.VERIFIED_OK;	
	}
	
	/**
	 * Returns a Java model status describing the problem related to this classpath entry if any, 
	 * a status object with code <code>IStatus.OK</code> if the entry is fine (that is, if the
	 * given classpath entry denotes a valid element to be referenced onto a classpath).
	 * 
	 * @param project the given java project
	 * @param entry the given classpath entry
	 * @param checkSourceAttachment a flag to determine if source attachement should be checked
	 * @param recurseInContainers flag indicating whether validation should be applied to container entries recursively
	 * @return a java model status describing the problem related to this classpath entry if any, a status object with code <code>IStatus.OK</code> if the entry is fine
	 */
	public static IJavaModelStatus validateClasspathEntry(IJavaProject project, IClasspathEntry entry, boolean checkSourceAttachment, boolean recurseInContainers){
		
		IWorkspaceRoot workspaceRoot = ResourcesPlugin.getWorkspace().getRoot();			
		IPath path = entry.getPath();
	
		// Build some common strings for status message
		String projectName = project.getElementName();
		boolean pathStartsWithProject = projectName.equals(path.segment(0));
		String entryPathMsg = pathStartsWithProject ? path.removeFirstSegments(1).makeRelative().toString() : path.toString();
	
		switch(entry.getEntryKind()){
	
			// container entry check
			case IClasspathEntry.CPE_CONTAINER :
				if (path != null && path.segmentCount() >= 1){
					try {
						IClasspathContainer container = JavaModelManager.getJavaModelManager().getClasspathContainer(path, project);
						// container retrieval is performing validation check on container entry kinds.
						if (container == null){
							return new JavaModelStatus(IJavaModelStatusConstants.CP_CONTAINER_PATH_UNBOUND, project, path);
						} else if (container == JavaModelManager.CONTAINER_INITIALIZATION_IN_PROGRESS) {
							// don't create a marker if initialization is in progress (case of cp initialization batching)
							return JavaModelStatus.VERIFIED_OK;
						}
						IClasspathEntry[] containerEntries = container.getClasspathEntries();
						if (containerEntries != null){
							for (int i = 0, length = containerEntries.length; i < length; i++){
								IClasspathEntry containerEntry = containerEntries[i];
								int kind = containerEntry == null ? 0 : containerEntry.getEntryKind();
								if (containerEntry == null
									|| kind == IClasspathEntry.CPE_SOURCE
									|| kind == IClasspathEntry.CPE_VARIABLE
									|| kind == IClasspathEntry.CPE_CONTAINER){
										String description = container.getDescription();
										if (description == null) description = path.makeRelative().toString();
										return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CP_CONTAINER_ENTRY, project, path);
								}
								if (recurseInContainers) {
									IJavaModelStatus containerEntryStatus = validateClasspathEntry(project, containerEntry, checkSourceAttachment, recurseInContainers);
									if (!containerEntryStatus.isOK()){
										return containerEntryStatus;
									}
								} 
							}
						}
					} catch(JavaModelException e){
						return new JavaModelStatus(e);
					}
				} else {
					return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_illegalContainerPath, new String[] {entryPathMsg, projectName}));					 
				}
				break;
				
			// variable entry check
			case IClasspathEntry.CPE_VARIABLE :
				if (path != null && path.segmentCount() >= 1){
					try {
						entry = JavaCore.getResolvedClasspathEntry(entry);
					} catch (Assert.AssertionFailedException e) {
						// Catch the assertion failure and throw java model exception instead
						// see bug https://bugs.eclipse.org/bugs/show_bug.cgi?id=55992
						return new JavaModelStatus(IJavaModelStatusConstants.INVALID_PATH, e.getMessage());
					}
					if (entry == null){
						return new JavaModelStatus(IJavaModelStatusConstants.CP_VARIABLE_PATH_UNBOUND, project, path);
					}
					return validateClasspathEntry(project, entry, checkSourceAttachment, recurseInContainers);
				} else {
					return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_illegalVariablePath, new String[] {entryPathMsg, projectName}));					 
				}
	
			// library entry check
			case IClasspathEntry.CPE_LIBRARY :
				if (path != null && path.isAbsolute() && !path.isEmpty()) {
					IPath sourceAttachment = entry.getSourceAttachmentPath();
					Object target = JavaModel.getTarget(workspaceRoot, path, true);
					if (target != null && project.getOption(JavaCore.CORE_INCOMPATIBLE_JDK_LEVEL, true) != JavaCore.IGNORE) {
						long projectTargetJDK = CompilerOptions.versionToJdkLevel(project.getOption(JavaCore.COMPILER_CODEGEN_TARGET_PLATFORM, true));
						long libraryJDK = Util.getJdkLevel(target);
						if (libraryJDK != 0 && libraryJDK > projectTargetJDK) {
							return new JavaModelStatus(IJavaModelStatusConstants.INCOMPATIBLE_JDK_LEVEL, project, path, CompilerOptions.versionFromJdkLevel(libraryJDK)); 
						}
					}
					if (target instanceof IResource){
						IResource resolvedResource = (IResource) target;
						switch(resolvedResource.getType()){
							case IResource.FILE :
								if (org.eclipse.jdt.internal.compiler.util.Util.isArchiveFileName(resolvedResource.getName())) {
									if (checkSourceAttachment 
										&& sourceAttachment != null
										&& !sourceAttachment.isEmpty()
										&& JavaModel.getTarget(workspaceRoot, sourceAttachment, true) == null){
										return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_unboundSourceAttachment, new String [] {sourceAttachment.toString(), path.toString(), projectName})); 
									}
								} else {
									return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_illegalLibraryArchive, new String[] {entryPathMsg, projectName})); 
								}
								break;
							case IResource.FOLDER :	// internal binary folder
								if (checkSourceAttachment 
									&& sourceAttachment != null 
									&& !sourceAttachment.isEmpty()
									&& JavaModel.getTarget(workspaceRoot, sourceAttachment, true) == null){
									return  new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_unboundSourceAttachment, new String [] {sourceAttachment.toString(), path.toString(), projectName})); 
								}
						}
					} else if (target instanceof File){
					    File file = (File) target;
					    if (!file.isFile()) {
							return  new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_illegalExternalFolder, new String[] {path.toOSString(), projectName})); 
					    } else if (!org.eclipse.jdt.internal.compiler.util.Util.isArchiveFileName(file.getName())) {
							return  new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_illegalLibraryArchive, (new String[] {path.toOSString(), projectName}))); 
					    } else if (checkSourceAttachment 
								&& sourceAttachment != null 
								&& !sourceAttachment.isEmpty()
								&& JavaModel.getTarget(workspaceRoot, sourceAttachment, true) == null){
								return  new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_unboundSourceAttachment, new String [] {sourceAttachment.toString(), path.toOSString(), projectName})); 
					    }
					} else {
						boolean isExternal = path.getDevice() != null || !workspaceRoot.getProject(path.segment(0)).exists();
						if (isExternal) {
							return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_unboundLibrary, new String[] {path.toOSString(), projectName})); 
						} else {
							return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_unboundLibrary, new String[] {entryPathMsg, projectName})); 
						}
					}
				} else {
					return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_illegalLibraryPath, new String[] {entryPathMsg, projectName})); 
				}
				break;
	
			// project entry check
			case IClasspathEntry.CPE_PROJECT :
				if (path != null && path.isAbsolute() && !path.isEmpty()) {
					IProject prereqProjectRsc = workspaceRoot.getProject(path.segment(0));
					IJavaProject prereqProject = JavaCore.create(prereqProjectRsc);
					try {
						if (!prereqProjectRsc.exists() || !prereqProjectRsc.hasNature(JavaCore.NATURE_ID)){
							return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_unboundProject, new String[] {path.segment(0), projectName})); 
						}
						if (!prereqProjectRsc.isOpen()){
							return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_closedProject, new String[] {path.segment(0)})); 
						}
						if (project.getOption(JavaCore.CORE_INCOMPATIBLE_JDK_LEVEL, true) != JavaCore.IGNORE) {
							long projectTargetJDK = CompilerOptions.versionToJdkLevel(project.getOption(JavaCore.COMPILER_CODEGEN_TARGET_PLATFORM, true));
							long prereqProjectTargetJDK = CompilerOptions.versionToJdkLevel(prereqProject.getOption(JavaCore.COMPILER_CODEGEN_TARGET_PLATFORM, true));
							if (prereqProjectTargetJDK > projectTargetJDK) {
								return new JavaModelStatus(IJavaModelStatusConstants.INCOMPATIBLE_JDK_LEVEL, project, path, CompilerOptions.versionFromJdkLevel(prereqProjectTargetJDK)); 
							}
						}
					} catch (CoreException e){
						return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_unboundProject, new String[] {path.segment(0), projectName})); 
					}
				} else {
					return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_illegalProjectPath, new String[] {path.segment(0), projectName})); 
				}
				break;
	
			// project source folder
			case IClasspathEntry.CPE_SOURCE :
				if (((entry.getInclusionPatterns() != null && entry.getInclusionPatterns().length > 0)
				        	|| (entry.getExclusionPatterns() != null && entry.getExclusionPatterns().length > 0))
						&& JavaCore.DISABLED.equals(project.getOption(JavaCore.CORE_ENABLE_CLASSPATH_EXCLUSION_PATTERNS, true))) {
					return new JavaModelStatus(IJavaModelStatusConstants.DISABLED_CP_EXCLUSION_PATTERNS, project, path);
				}
				if (entry.getOutputLocation() != null && JavaCore.DISABLED.equals(project.getOption(JavaCore.CORE_ENABLE_CLASSPATH_MULTIPLE_OUTPUT_LOCATIONS, true))) {
					return new JavaModelStatus(IJavaModelStatusConstants.DISABLED_CP_MULTIPLE_OUTPUT_LOCATIONS, project, path);
				}
				if (path != null && path.isAbsolute() && !path.isEmpty()) {
					IPath projectPath= project.getProject().getFullPath();
					if (!projectPath.isPrefixOf(path) || JavaModel.getTarget(workspaceRoot, path, true) == null){
						return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_unboundSourceFolder, new String[] {entryPathMsg, projectName})); 
					}
				} else {
					return new JavaModelStatus(IJavaModelStatusConstants.INVALID_CLASSPATH, Messages.bind(Messages.classpath_illegalSourceFolderPath, new String[] {entryPathMsg, projectName})); 
				}
				break;
		}
		return JavaModelStatus.VERIFIED_OK;		
	}
}