/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.core;

import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Map;

import org.eclipse.core.resources.*;
import org.eclipse.core.resources.IContainer;
import org.eclipse.core.resources.IFolder;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.runtime.*;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.jdt.core.*;
import org.eclipse.jdt.core.compiler.CharOperation;
import org.eclipse.jdt.internal.core.util.MementoTokenizer;
import org.eclipse.jdt.internal.core.util.Util;

/**
 * @see IPackageFragmentRoot
 */
public class PackageFragmentRoot extends Openable implements IPackageFragmentRoot {

	/**
	 * The delimiter between the source path and root path in the
	 * attachment server property.
	 */
	protected final static char ATTACHMENT_PROPERTY_DELIMITER= '*';
	/*
	 * No source attachment property
	 */
	protected final static String NO_SOURCE_ATTACHMENT = ""; //$NON-NLS-1$
	/*
	 * No source mapper singleton
	 */
	protected final static SourceMapper NO_SOURCE_MAPPER = new SourceMapper();

	/**
	 * The resource associated with this root.
	 * (an IResource or a java.io.File (for external jar only))
	 */
	protected Object resource;
	
/**
 * Constructs a package fragment root which is the root of the java package
 * directory hierarchy.
 */
protected PackageFragmentRoot(IResource resource, JavaProject project, String name) {
	super(project, name);
	this.resource = resource;
}

/**
 * @see IPackageFragmentRoot
 */
public void attachSource(IPath sourcePath, IPath rootPath, IProgressMonitor monitor) throws JavaModelException {
	try {
		verifyAttachSource(sourcePath);
		if (monitor != null) {
			monitor.beginTask(Util.bind("element.attachingSource"), 2); //$NON-NLS-1$
		}
		SourceMapper oldMapper= getSourceMapper();
		IWorkspace workspace = ResourcesPlugin.getWorkspace();
		boolean rootNeedsToBeClosed= false;

		if (sourcePath == null) {
			//source being detached
			rootNeedsToBeClosed= true;
			setSourceMapper(null);
		/* Disable deltas (see 1GDTUSD)
			// fire a delta to notify the UI about the source detachement.
			JavaModelManager manager = (JavaModelManager) JavaModelManager.getJavaModelManager();
			JavaModel model = (JavaModel) getJavaModel();
			JavaElementDelta attachedSourceDelta = new JavaElementDelta(model);
			attachedSourceDelta .sourceDetached(this); // this would be a PackageFragmentRoot
			manager.registerResourceDelta(attachedSourceDelta );
			manager.fire(); // maybe you want to fire the change later. Let us know about it.
		*/
		} else {
		/*
			// fire a delta to notify the UI about the source attachement.
			JavaModelManager manager = (JavaModelManager) JavaModelManager.getJavaModelManager();
			JavaModel model = (JavaModel) getJavaModel();
			JavaElementDelta attachedSourceDelta = new JavaElementDelta(model);
			attachedSourceDelta .sourceAttached(this); // this would be a PackageFragmentRoot
			manager.registerResourceDelta(attachedSourceDelta );
			manager.fire(); // maybe you want to fire the change later. Let us know about it.
		 */

			//check if different from the current attachment
			IPath storedSourcePath= getSourceAttachmentPath();
			IPath storedRootPath= getSourceAttachmentRootPath();
			if (monitor != null) {
				monitor.worked(1);
			}
			if (storedSourcePath != null) {
				if (!(storedSourcePath.equals(sourcePath) && (rootPath != null && rootPath.equals(storedRootPath)) || storedRootPath == null)) {
					rootNeedsToBeClosed= true;
				}
			}
			// check if source path is valid
			Object target = JavaModel.getTarget(workspace.getRoot(), sourcePath, false);
			if (target == null) {
				if (monitor != null) {
					monitor.done();
				}
				throw new JavaModelException(new JavaModelStatus(IJavaModelStatusConstants.INVALID_PATH, sourcePath));
			}
			SourceMapper mapper = createSourceMapper(sourcePath, rootPath);
			if (rootPath == null && mapper.rootPath != null) {
				// as a side effect of calling the SourceMapper constructor, the root path was computed
				rootPath = new Path(mapper.rootPath);
			}
			setSourceMapper(mapper);
		}
		if (sourcePath == null) {
			setSourceAttachmentProperty(null); //remove the property
		} else {
			//set the property to the path of the mapped source
			setSourceAttachmentProperty(
				sourcePath.toString() 
				+ (rootPath == null ? "" : (ATTACHMENT_PROPERTY_DELIMITER + rootPath.toString()))); //$NON-NLS-1$
		}
		if (rootNeedsToBeClosed) {
			if (oldMapper != null) {
				oldMapper.close();
			}
			BufferManager manager= BufferManager.getDefaultBufferManager();
			Enumeration openBuffers= manager.getOpenBuffers();
			while (openBuffers.hasMoreElements()) {
				IBuffer buffer= (IBuffer) openBuffers.nextElement();
				IOpenable possibleMember= buffer.getOwner();
				if (isAncestorOf((IJavaElement) possibleMember)) {
					buffer.close();
				}
			}
			if (monitor != null) {
				monitor.worked(1);
			}
		}
	} catch (JavaModelException e) {
		setSourceAttachmentProperty(null); // loose info - will be recomputed
		throw e;
	} finally {
		if (monitor != null) {
			monitor.done();
		}
	}
}

/**
 * @see Openable
 */
protected boolean buildStructure(OpenableElementInfo info, IProgressMonitor pm, Map newElements, IResource underlyingResource) throws JavaModelException {
	
	// check whether this pkg fragment root can be opened
	if (!resourceExists() || !isOnClasspath()) {
		throw newNotPresentException();
	}

	((PackageFragmentRootInfo) info).setRootKind(determineKind(underlyingResource));
	return computeChildren(info, newElements);
}

SourceMapper createSourceMapper(IPath sourcePath, IPath rootPath) {
	SourceMapper mapper = new SourceMapper(
		sourcePath, 
		rootPath == null ? null : rootPath.toOSString(), 
		this.isExternal() ? JavaCore.getOptions() : this.getJavaProject().getOptions(true)); // only project options if associated with resource
	return mapper;
}
/*
 * @see org.eclipse.jdt.core.IPackageFragmentRoot#delete
 */
public void delete(
	int updateResourceFlags,
	int updateModelFlags,
	IProgressMonitor monitor)
	throws JavaModelException {

	DeletePackageFragmentRootOperation op = new DeletePackageFragmentRootOperation(this, updateResourceFlags, updateModelFlags);
	op.runOperation(monitor);
}

/**
 * Compute the package fragment children of this package fragment root.
 * 
 * @exception JavaModelException  The resource associated with this package fragment root does not exist
 */
protected boolean computeChildren(OpenableElementInfo info, Map newElements) throws JavaModelException {
	// Note the children are not opened (so not added to newElements) for a regular package fragment root
	// Howver they are opened for a Jar package fragment root (see JarPackageFragmentRoot#computeChildren)
	try {
		// the underlying resource may be a folder or a project (in the case that the project folder
		// is actually the package fragment root)
		IResource underlyingResource = getResource();
		if (underlyingResource.getType() == IResource.FOLDER || underlyingResource.getType() == IResource.PROJECT) {
			ArrayList vChildren = new ArrayList(5);
			IContainer rootFolder = (IContainer) underlyingResource;
			char[][] inclusionPatterns = fullInclusionPatternChars();
			char[][] exclusionPatterns = fullExclusionPatternChars();
			computeFolderChildren(rootFolder, !Util.isExcluded(rootFolder, inclusionPatterns, exclusionPatterns), "", vChildren, inclusionPatterns, exclusionPatterns); //$NON-NLS-1$
			IJavaElement[] children = new IJavaElement[vChildren.size()];
			vChildren.toArray(children);
			info.setChildren(children);
		}
	} catch (JavaModelException e) {
		//problem resolving children; structure remains unknown
		info.setChildren(new IJavaElement[]{});
		throw e;
	}
	return true;
}

/**
 * Starting at this folder, create package fragments and add the fragments that are not exclused
 * to the collection of children.
 * 
 * @exception JavaModelException  The resource associated with this package fragment does not exist
 */
protected void computeFolderChildren(IContainer folder, boolean isIncluded, String prefix, ArrayList vChildren, char[][] inclusionPatterns, char[][] exclusionPatterns) throws JavaModelException {

	if (isIncluded) {
	    IPackageFragment pkg = getPackageFragment(prefix);
		vChildren.add(pkg);
	}
	try {
		JavaProject javaProject = (JavaProject)getJavaProject();
		IResource[] members = folder.members();
		boolean hasIncluded = isIncluded;
		for (int i = 0, max = members.length; i < max; i++) {
			IResource member = members[i];
			String memberName = member.getName();
			
			switch(member.getType()) {
			    
			    case IResource.FOLDER:
					if (Util.isValidFolderNameForPackage(memberName)) {
					    boolean isMemberIncluded = !Util.isExcluded(member, inclusionPatterns, exclusionPatterns);
						// keep looking inside as long as included already, or may have child included due to inclusion patterns
					    if (isMemberIncluded || inclusionPatterns != null) { 
							// eliminate binary output only if nested inside direct subfolders
							if (javaProject.contains(member)) {
								String newPrefix;
								if (prefix.length() == 0) {
									newPrefix = memberName;
								} else {
									newPrefix = prefix + "." + memberName; //$NON-NLS-1$
								}
								computeFolderChildren((IFolder) member, isMemberIncluded, newPrefix, vChildren, inclusionPatterns, exclusionPatterns);
							}
						}
					}
			    	break;
			    case IResource.FILE:
			        // inclusion filter may only include files, in which case we still want to include the immediate parent package (lazily)
					if (!hasIncluded
								&& Util.isValidCompilationUnitName(memberName)
								&& !Util.isExcluded(member, inclusionPatterns, exclusionPatterns)) {
						hasIncluded = true;
					    IPackageFragment pkg = getPackageFragment(prefix);
					    vChildren.add(pkg); 
					}
			        break;
			}
		}
	} catch(IllegalArgumentException e){
		throw new JavaModelException(e, IJavaModelStatusConstants.ELEMENT_DOES_NOT_EXIST); // could be thrown by ElementTree when path is not found
	} catch (CoreException e) {
		throw new JavaModelException(e);
	}
}

/*
 * @see org.eclipse.jdt.core.IPackageFragmentRoot#copy
 */
public void copy(
	IPath destination,
	int updateResourceFlags,
	int updateModelFlags,
	IClasspathEntry sibling,
	IProgressMonitor monitor)
	throws JavaModelException {
		
	CopyPackageFragmentRootOperation op = 
		new CopyPackageFragmentRootOperation(this, destination, updateResourceFlags, updateModelFlags, sibling);
	op.runOperation(monitor);
}

/**
 * Returns a new element info for this element.
 */
protected Object createElementInfo() {
	return new PackageFragmentRootInfo();
}

/**
 * @see IPackageFragmentRoot
 */
public IPackageFragment createPackageFragment(String pkgName, boolean force, IProgressMonitor monitor) throws JavaModelException {
	CreatePackageFragmentOperation op = new CreatePackageFragmentOperation(this, pkgName, force);
	op.runOperation(monitor);
	return getPackageFragment(pkgName);
}

/**
 * Returns the root's kind - K_SOURCE or K_BINARY, defaults
 * to K_SOURCE if it is not on the classpath.
 *
 * @exception NotPresentException if the project and root do
 * 		not exist.
 */
protected int determineKind(IResource underlyingResource) throws JavaModelException {
	IClasspathEntry[] entries= ((JavaProject)getJavaProject()).getExpandedClasspath(true);
	for (int i= 0; i < entries.length; i++) {
		IClasspathEntry entry= entries[i];
		if (entry.getPath().equals(underlyingResource.getFullPath())) {
			return entry.getContentKind();
		}
	}
	return IPackageFragmentRoot.K_SOURCE;
}

/**
 * Compares two objects for equality;
 * for <code>PackageFragmentRoot</code>s, equality is having the
 * same <code>JavaModel</code>, same resources, and occurrence count.
 *
 */
public boolean equals(Object o) {
	if (this == o)
		return true;
	if (!(o instanceof PackageFragmentRoot))
		return false;
	PackageFragmentRoot other = (PackageFragmentRoot) o;
	return this.resource.equals(other.resource) &&
			this.occurrenceCount == other.occurrenceCount;
}

/**
 * @see IJavaElement
 */
public boolean exists() {
	return super.exists() && isOnClasspath();
}

public IClasspathEntry findSourceAttachmentRecommendation() {
	try {
		IPath rootPath = this.getPath();
		IClasspathEntry entry;
		IWorkspaceRoot workspaceRoot = ResourcesPlugin.getWorkspace().getRoot();
		
		// try on enclosing project first
		JavaProject parentProject = (JavaProject) getJavaProject();
		try {
			entry = parentProject.getClasspathEntryFor(rootPath);
			if (entry != null){
				Object target = JavaModel.getTarget(workspaceRoot, entry.getSourceAttachmentPath(), true);
				if (target instanceof IFile){
					IFile file = (IFile) target;
					if (org.eclipse.jdt.internal.compiler.util.Util.isArchiveFileName(file.getName())){
						return entry;
					}
				} else if (target instanceof IFolder) {
					return entry;
				}
				if (target instanceof java.io.File){
					java.io.File file = (java.io.File) target;
					if (file.isFile()) {
						if (org.eclipse.jdt.internal.compiler.util.Util.isArchiveFileName(file.getName())){
							return entry;
						}
					} else {
						// external directory
						return entry;
					}
				}
			}
		} catch(JavaModelException e){
			// ignore
		}
		
		// iterate over all projects
		IJavaModel model = getJavaModel();
		IJavaProject[] jProjects = model.getJavaProjects();
		for (int i = 0, max = jProjects.length; i < max; i++){
			JavaProject jProject = (JavaProject) jProjects[i];
			if (jProject == parentProject) continue; // already done
			try {
				entry = jProject.getClasspathEntryFor(rootPath);
				if (entry != null){
					Object target = JavaModel.getTarget(workspaceRoot, entry.getSourceAttachmentPath(), true);
					if (target instanceof IFile){
						IFile file = (IFile) target;
						if (org.eclipse.jdt.internal.compiler.util.Util.isArchiveFileName(file.getName())){
							return entry;
						}
					} else if (target instanceof IFolder) {
						return entry;
					}
					if (target instanceof java.io.File){
						java.io.File file = (java.io.File) target;
						if (file.isFile()) {
							if (org.eclipse.jdt.internal.compiler.util.Util.isArchiveFileName(file.getName())){
								return entry;
							}
						} else {
							// external directory
							return entry;
						}
					}
				}
			} catch(JavaModelException e){
				// ignore
			}
		}
	} catch(JavaModelException e){
		// ignore
	}

	return null;
}

/*
 * Returns the exclusion patterns from the classpath entry associated with this root.
 */
public char[][] fullExclusionPatternChars() {
	try {
		if (this.isOpen() && this.getKind() != IPackageFragmentRoot.K_SOURCE) return null;
		ClasspathEntry entry = (ClasspathEntry)getRawClasspathEntry();
		if (entry == null) {
			return null;
		} else {
			return entry.fullExclusionPatternChars();
		}
	} catch (JavaModelException e) { 
		return null;
	}
}		

/*
 * Returns the inclusion patterns from the classpath entry associated with this root.
 */
public char[][] fullInclusionPatternChars() {
	try {
		if (this.isOpen() && this.getKind() != IPackageFragmentRoot.K_SOURCE) return null;
		ClasspathEntry entry = (ClasspathEntry)getRawClasspathEntry();
		if (entry == null) {
			return null;
		} else {
			return entry.fullInclusionPatternChars();
		}
	} catch (JavaModelException e) { 
		return null;
	}
}		

/**
 * @see IJavaElement
 */
public int getElementType() {
	return PACKAGE_FRAGMENT_ROOT;
}
/**
 * @see JavaElement#getHandleMemento()
 */
protected char getHandleMementoDelimiter() {
	return JavaElement.JEM_PACKAGEFRAGMENTROOT;
}
/*
 * @see JavaElement
 */
public IJavaElement getHandleFromMemento(String token, MementoTokenizer memento, WorkingCopyOwner owner) {
	switch (token.charAt(0)) {
		case JEM_COUNT:
			return getHandleUpdatingCountFromMemento(memento, owner);
		case JEM_PACKAGEFRAGMENT:
			String pkgName;
			if (memento.hasMoreTokens()) {
				pkgName = memento.nextToken();
				char firstChar = pkgName.charAt(0);
				if (firstChar == JEM_CLASSFILE || firstChar == JEM_COMPILATIONUNIT || firstChar == JEM_COUNT) {
					token = pkgName;
					pkgName = IPackageFragment.DEFAULT_PACKAGE_NAME;
				} else {
					token = null;
				}
			} else {
				pkgName = IPackageFragment.DEFAULT_PACKAGE_NAME;
				token = null;
			}
			JavaElement pkg = (JavaElement)getPackageFragment(pkgName);
			if (token == null) {
				return pkg.getHandleFromMemento(memento, owner);
			} else {
				return pkg.getHandleFromMemento(token, memento, owner);
			}
	}
	return null;
}
/**
 * @see JavaElement#getHandleMemento()
 */
public String getHandleMemento(){
	IPath path;
	IResource underlyingResource = getResource();
	if (underlyingResource != null) {
		// internal jar or regular root
		if (getResource().getProject().equals(getJavaProject().getProject())) {
			path = underlyingResource.getProjectRelativePath();
		} else {
			path = underlyingResource.getFullPath();
		}
	} else {
		// external jar
		path = getPath();
	}
	StringBuffer buff= new StringBuffer(((JavaElement)getParent()).getHandleMemento());
	buff.append(getHandleMementoDelimiter());
	escapeMementoName(buff, path.toString()); 
	if (this.occurrenceCount > 1) {
		buff.append(JEM_COUNT);
		buff.append(this.occurrenceCount);
	}
	return buff.toString();
}
/**
 * @see IPackageFragmentRoot
 */
public int getKind() throws JavaModelException {
	return ((PackageFragmentRootInfo)getElementInfo()).getRootKind();
}

/**
 * Returns an array of non-java resources contained in the receiver.
 */
public Object[] getNonJavaResources() throws JavaModelException {
	return ((PackageFragmentRootInfo) getElementInfo()).getNonJavaResources(getJavaProject(), getResource(), this);
}

/**
 * @see IPackageFragmentRoot
 */
public IPackageFragment getPackageFragment(String packageName) {
	if (packageName.indexOf(' ') != -1) { // tolerate package names with spaces (e.g. 'x . y') (http://bugs.eclipse.org/bugs/show_bug.cgi?id=21957)
		char[][] compoundName = Util.toCompoundChars(packageName);
		StringBuffer buffer = new StringBuffer(packageName.length());
		for (int i = 0, length = compoundName.length; i < length; i++) {
			buffer.append(CharOperation.trim(compoundName[i]));
			if (i != length-1) {
				buffer.append('.');
			}
		}
		packageName = buffer.toString();
	}
	return new PackageFragment(this, packageName);
}

/**
 * Returns the package name for the given folder
 * (which is a decendent of this root).
 */
protected String getPackageName(IFolder folder) {
	IPath myPath= getPath();
	IPath pkgPath= folder.getFullPath();
	int mySegmentCount= myPath.segmentCount();
	int pkgSegmentCount= pkgPath.segmentCount();
	StringBuffer pkgName = new StringBuffer(IPackageFragment.DEFAULT_PACKAGE_NAME);
	for (int i= mySegmentCount; i < pkgSegmentCount; i++) {
		if (i > mySegmentCount) {
			pkgName.append('.');
		}
		pkgName.append(pkgPath.segment(i));
	}
	return pkgName.toString();
}

/**
 * @see IJavaElement
 */
public IPath getPath() {
	return getResource().getFullPath();
}

/*
 * @see IPackageFragmentRoot 
 */
public IClasspathEntry getRawClasspathEntry() throws JavaModelException {

	IClasspathEntry rawEntry = null;
	JavaProject project = (JavaProject)this.getJavaProject();
	project.getResolvedClasspath(true); // force the reverse rawEntry cache to be populated
	JavaModelManager.PerProjectInfo perProjectInfo = project.getPerProjectInfo();
	if (perProjectInfo != null && perProjectInfo.resolvedPathToRawEntries != null) {
		rawEntry = (IClasspathEntry) perProjectInfo.resolvedPathToRawEntries.get(this.getPath());
	}
	return rawEntry;
}

/*
 * @see IJavaElement
 */
public IResource getResource() {
	return (IResource)this.resource;
}

/**
 * @see IPackageFragmentRoot
 */
public IPath getSourceAttachmentPath() throws JavaModelException {
	if (getKind() != K_BINARY) return null;
	
	String serverPathString= getSourceAttachmentProperty();
	if (serverPathString == null) {
		return null;
	}
	int index= serverPathString.lastIndexOf(ATTACHMENT_PROPERTY_DELIMITER);
	if (index < 0) {
		// no root path specified
		return new Path(serverPathString);
	} else {
		String serverSourcePathString= serverPathString.substring(0, index);
		return new Path(serverSourcePathString);
	}
}

/**
 * Returns the server property for this package fragment root's
 * source attachement.
 */
protected String getSourceAttachmentProperty() throws JavaModelException {
	String propertyString = null;
	QualifiedName qName= getSourceAttachmentPropertyName();
	try {
		propertyString = ResourcesPlugin.getWorkspace().getRoot().getPersistentProperty(qName);
		
		// if no existing source attachment information, then lookup a recommendation from classpath entries
		if (propertyString == null) {
			IClasspathEntry recommendation = findSourceAttachmentRecommendation();
			if (recommendation != null) {
				IPath rootPath = recommendation.getSourceAttachmentRootPath();
				propertyString = 
					recommendation.getSourceAttachmentPath().toString() 
						+ ((rootPath == null) 
							? "" : //$NON-NLS-1$
							(ATTACHMENT_PROPERTY_DELIMITER + rootPath.toString())); 
				setSourceAttachmentProperty(propertyString);
			} else {
				// mark as being already looked up
				setSourceAttachmentProperty(NO_SOURCE_ATTACHMENT);
			}
		} else if (NO_SOURCE_ATTACHMENT.equals(propertyString)) {
			// already looked up and no source attachment found
			return null;
		}
		return propertyString;
	} catch (CoreException ce) {
		throw new JavaModelException(ce);
	}
}
	
/**
 * Returns the qualified name for the source attachment property
 * of this root.
 */
protected QualifiedName getSourceAttachmentPropertyName() {
	return new QualifiedName(JavaCore.PLUGIN_ID, "sourceattachment: " + this.getPath().toOSString()); //$NON-NLS-1$
}

public void setSourceAttachmentProperty(String property) {
	try {
		ResourcesPlugin.getWorkspace().getRoot().setPersistentProperty(this.getSourceAttachmentPropertyName(), property);
	} catch (CoreException ce) {
		// ignore
	}
}

/**
 * For use by <code>AttachSourceOperation</code> only.
 * Sets the source mapper associated with this root.
 */
public void setSourceMapper(SourceMapper mapper) throws JavaModelException {
	((PackageFragmentRootInfo) getElementInfo()).setSourceMapper(mapper);
}


/**
 * @see IPackageFragmentRoot
 */
public IPath getSourceAttachmentRootPath() throws JavaModelException {
	if (getKind() != K_BINARY) return null;
	
	String serverPathString= getSourceAttachmentProperty();
	if (serverPathString == null) {
		return null;
	}
	int index = serverPathString.lastIndexOf(ATTACHMENT_PROPERTY_DELIMITER);
	if (index == -1) return null;
	String serverRootPathString= IPackageFragmentRoot.DEFAULT_PACKAGEROOT_PATH;
	if (index != serverPathString.length() - 1) {
		serverRootPathString= serverPathString.substring(index + 1);
	}
	return new Path(serverRootPathString);
}

/**
 * @see JavaElement
 */
public SourceMapper getSourceMapper() {
	SourceMapper mapper;
	try {
		PackageFragmentRootInfo rootInfo = (PackageFragmentRootInfo) getElementInfo();
		mapper = rootInfo.getSourceMapper();
		if (mapper == null) {
			// first call to this method
			IPath sourcePath= getSourceAttachmentPath();
			if (sourcePath != null) {
				IPath rootPath= getSourceAttachmentRootPath();
				mapper = this.createSourceMapper(sourcePath, rootPath);
				if (rootPath == null && mapper.rootPath != null) {
					// as a side effect of calling the SourceMapper constructor, the root path was computed
					rootPath = new Path(mapper.rootPath);
					
					//set the property to the path of the mapped source
					this.setSourceAttachmentProperty(
						sourcePath.toString() 
						+ ATTACHMENT_PROPERTY_DELIMITER 
						+ rootPath.toString());
				}
				rootInfo.setSourceMapper(mapper);
			} else {
				// remember that no source is attached
				rootInfo.setSourceMapper(NO_SOURCE_MAPPER);
				mapper = null;
			}
		} else if (mapper == NO_SOURCE_MAPPER) {
			// a previous call to this method found out that no source was attached
			mapper = null;
		}
	} catch (JavaModelException e) {
		// no source can be attached
		mapper = null;
	}
	return mapper;
}

/**
 * @see IJavaElement
 */
public IResource getUnderlyingResource() throws JavaModelException {
	if (!exists()) throw newNotPresentException();
	return getResource();
}

/**
 * @see IParent 
 */
public boolean hasChildren() throws JavaModelException {
	// a package fragment root always has the default package as a child
	return true;
}

public int hashCode() {
	return this.resource.hashCode();
}

/**
 * @see IPackageFragmentRoot
 */
public boolean isArchive() {
	return false;
}

/**
 * @see IPackageFragmentRoot
 */
public boolean isExternal() {
	return false;
}

/*
 * Returns whether this package fragment root is on the classpath of its project.
 */
protected boolean isOnClasspath() {
	
	IPath path = this.getPath();
	try {
		// check package fragment root on classpath of its project
		IJavaProject project = this.getJavaProject();
		IClasspathEntry[] classpath = project.getResolvedClasspath(true);	
		for (int i = 0, length = classpath.length; i < length; i++) {
			IClasspathEntry entry = classpath[i];
			if (entry.getPath().equals(path)) {
				return true;
			}
		}
	} catch(JavaModelException e){
		// could not read classpath, then assume it is outside
	}
	return false;
}
/*
 * @see org.eclipse.jdt.core.IPackageFragmentRoot#move
 */
public void move(
	IPath destination,
	int updateResourceFlags,
	int updateModelFlags,
	IClasspathEntry sibling,
	IProgressMonitor monitor)
	throws JavaModelException {

	MovePackageFragmentRootOperation op = 
		new MovePackageFragmentRootOperation(this, destination, updateResourceFlags, updateModelFlags, sibling);
	op.runOperation(monitor);
}

/**
 * @private Debugging purposes
 */
protected void toStringInfo(int tab, StringBuffer buffer, Object info) {
	buffer.append(this.tabString(tab));
	if (getElementName().length() == 0) {
		buffer.append("<project root>"); //$NON-NLS-1$
	} else {
		IPath path = getPath();
		if (getJavaProject().getElementName().equals(path.segment(0))) {
			buffer.append(path.removeFirstSegments(1).makeRelative());
		} else {
			buffer.append(path);
		}
	}
	if (info == null) {
		buffer.append(" (not open)"); //$NON-NLS-1$
	}
}

/**
 * Possible failures: <ul>
 *  <li>ELEMENT_NOT_PRESENT - the root supplied to the operation
 *      does not exist
 *  <li>INVALID_ELEMENT_TYPES - the root is not of kind K_BINARY
 *   <li>RELATIVE_PATH - the path supplied to this operation must be
 *      an absolute path
 *  </ul>
 */
protected void verifyAttachSource(IPath sourcePath) throws JavaModelException {
	if (!exists()) {
		throw newNotPresentException();
	} else if (this.getKind() != K_BINARY) {
		throw new JavaModelException(new JavaModelStatus(IJavaModelStatusConstants.INVALID_ELEMENT_TYPES, this));
	} else if (sourcePath != null && !sourcePath.isAbsolute()) {
		throw new JavaModelException(new JavaModelStatus(IJavaModelStatusConstants.RELATIVE_PATH, sourcePath));
	}
}

}