bundles/org.eclipse.equinox.p2.artifact.repository/src/org/eclipse/equinox/internal/p2/artifact/repository/simple/SimpleArtifactRepositoryIO.java - equinox/rt.equinox.p2 - Git at Google

 /*******************************************************************************
  * Copyright (c) 2007, 2008 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.equinox.internal.p2.artifact.repository.simple;

 import java.io.*;
 import java.net.URL;
 import java.util.*;
 import javax.xml.parsers.ParserConfigurationException;
 import org.eclipse.core.runtime.*;
 import org.eclipse.equinox.internal.p2.artifact.repository.Activator;
 import org.eclipse.equinox.internal.p2.artifact.repository.Messages;
 import org.eclipse.equinox.internal.p2.core.helpers.LogHelper;
 import org.eclipse.equinox.internal.p2.core.helpers.OrderedProperties;
 import org.eclipse.equinox.internal.p2.metadata.ArtifactKey;
 import org.eclipse.equinox.internal.p2.persistence.XMLParser;
 import org.eclipse.equinox.internal.p2.persistence.XMLWriter;
 import org.eclipse.equinox.internal.provisional.p2.artifact.repository.ArtifactDescriptor;
 import org.eclipse.equinox.internal.provisional.p2.artifact.repository.IArtifactRepository;
 import org.eclipse.equinox.internal.provisional.p2.artifact.repository.processing.ProcessingStepDescriptor;
 import org.eclipse.equinox.internal.provisional.p2.core.ProvisionException;
 import org.eclipse.equinox.internal.provisional.p2.metadata.IArtifactKey;
 import org.eclipse.osgi.service.resolver.VersionRange;
 import org.eclipse.osgi.util.NLS;
 import org.osgi.framework.BundleContext;
 import org.osgi.framework.Version;
 import org.xml.sax.*;

 /**
  * This class reads and writes artifact repository metadata
  * (e.g. table of contents files);
  *
  * This class is not used for reading or writing the actual artifacts.
  */

 // TODO: Should a registration/factory mechanism be supported
 //		 for getting a repository reader/writer given a repository type
 public class SimpleArtifactRepositoryIO {

 	/**
 	 * Writes the given artifact repository to the stream.
 	 * This method performs buffering, and closes the stream when finished.
 	 */
 	public void write(SimpleArtifactRepository repository, OutputStream output) {
 		OutputStream bufferedOutput = null;
 		try {
 			try {
 				bufferedOutput = new BufferedOutputStream(output);
 				Writer repositoryWriter = new Writer(bufferedOutput);
 				repositoryWriter.write(repository);
 			} finally {
 				if (bufferedOutput != null) {
 					bufferedOutput.close();
 				}
 			}
 		} catch (IOException ioe) {
 			// TODO shouldn't this throw a core exception?
 			ioe.printStackTrace();
 		}
 	}

 	/**
 	 * Reads the artifact repository from the given stream,
 	 * and returns the contained array of abstract artifact repositories.
 	 *
 	 * This method performs buffering, and closes the stream when finished.
 	 */
 	public IArtifactRepository read(URL location, InputStream input, IProgressMonitor monitor) throws ProvisionException {
 		BufferedInputStream bufferedInput = null;
 		try {
 			try {
 				bufferedInput = new BufferedInputStream(input);
 				Parser repositoryParser = new Parser(Activator.getContext(), Activator.ID);
 				repositoryParser.parse(input);
 				IStatus result = repositoryParser.getStatus();
 				switch (result.getSeverity()) {
 					case IStatus.CANCEL :
 						throw new OperationCanceledException();
 					case IStatus.ERROR :
 						throw new ProvisionException(result);
 					case IStatus.WARNING :
 					case IStatus.INFO :
 						LogHelper.log(result);
 				}
 				return repositoryParser.getRepository();
 			} finally {
 				if (bufferedInput != null)
 					bufferedInput.close();
 			}
 		} catch (IOException ioe) {
 			String msg = NLS.bind(Messages.io_failedRead, location);
 			throw new ProvisionException(new Status(IStatus.ERROR, Activator.ID, ProvisionException.REPOSITORY_FAILED_READ, msg, ioe));
 		}
 	}

 	private interface XMLConstants extends org.eclipse.equinox.internal.p2.persistence.XMLConstants {

 		// Constants defining the structure of the XML for a SimpleArtifactRepository

 		// A format version number for simple artifact repository XML.
 		public static final Version CURRENT_VERSION = new Version(1, 0, 0);
 		public static final VersionRange XML_TOLERANCE = new VersionRange(CURRENT_VERSION, true, new Version(2, 0, 0), false);

 		// Constants for processing instructions
 		public static final String PI_REPOSITORY_TARGET = "artifactRepository"; //$NON-NLS-1$
 		public static XMLWriter.ProcessingInstruction[] PI_DEFAULTS = new XMLWriter.ProcessingInstruction[] {XMLWriter.ProcessingInstruction.makeClassVersionInstruction(PI_REPOSITORY_TARGET, SimpleArtifactRepository.class, CURRENT_VERSION)};

 		// Constants for artifact repository elements
 		public static final String REPOSITORY_ELEMENT = "repository"; //$NON-NLS-1$
 		public static final String REPOSITORY_PROPERTIES_ELEMENT = "repositoryProperties"; //$NON-NLS-1$
 		public static final String MAPPING_RULES_ELEMENT = "mappings"; //$NON-NLS-1$
 		public static final String MAPPING_RULE_ELEMENT = "rule"; //$NON-NLS-1$
 		public static final String ARTIFACTS_ELEMENT = "artifacts"; //$NON-NLS-1$
 		public static final String ARTIFACT_ELEMENT = "artifact"; //$NON-NLS-1$
 		public static final String PROCESSING_STEPS_ELEMENT = "processing"; //$NON-NLS-1$
 		public static final String PROCESSING_STEP_ELEMENT = "step"; //$NON-NLS-1$

 		// Constants for attributes of artifact repository elements
 		public static final String VERIFY_SIGNATURE_ATTRIBUTE = "verify"; //$NON-NLS-1$

 		public static final String MAPPING_RULE_FILTER_ATTRIBUTE = "filter"; //$NON-NLS-1$
 		public static final String MAPPING_RULE_OUTPUT_ATTRIBUTE = "output"; //$NON-NLS-1$

 		public static final String ARTIFACT_CLASSIFIER_ATTRIBUTE = CLASSIFIER_ATTRIBUTE;

 		public static final String STEP_DATA_ATTRIBUTE = "data"; //$NON-NLS-1$
 		public static final String STEP_REQUIRED_ATTRIBUTE = "required"; //$NON-NLS-1$
 	}

 	// XML writer for a SimpleArtifactRepository
 	protected class Writer extends XMLWriter implements XMLConstants {

 		public Writer(OutputStream output) throws IOException {
 			super(output, PI_DEFAULTS);
 		}

 		/**
 		 * Write the given artifact repository to the output stream.
 		 */
 		public void write(SimpleArtifactRepository repository) {
 			start(REPOSITORY_ELEMENT);
 			attribute(NAME_ATTRIBUTE, repository.getName());
 			attribute(TYPE_ATTRIBUTE, repository.getType());
 			attribute(VERSION_ATTRIBUTE, repository.getVersion());
 			attributeOptional(PROVIDER_ATTRIBUTE, repository.getProvider());
 			attributeOptional(DESCRIPTION_ATTRIBUTE, repository.getDescription()); // TODO: could be cdata?
 			attribute(VERIFY_SIGNATURE_ATTRIBUTE, repository.getSignatureVerification(), false);

 			writeProperties(repository.getProperties());
 			writeMappingRules(repository.getRules());
 			writeArtifacts(repository.getDescriptors());

 			end(REPOSITORY_ELEMENT);
 			flush();
 		}

 		private void writeMappingRules(String[][] rules) {
 			if (rules.length > 0) {
 				start(MAPPING_RULES_ELEMENT);
 				attribute(COLLECTION_SIZE_ATTRIBUTE, rules.length);
 				for (int i = 0; i < rules.length; i++) {
 					start(MAPPING_RULE_ELEMENT);
 					attribute(MAPPING_RULE_FILTER_ATTRIBUTE, rules[i][0]);
 					attribute(MAPPING_RULE_OUTPUT_ATTRIBUTE, rules[i][1]);
 					end(MAPPING_RULE_ELEMENT);
 				}
 				end(MAPPING_RULES_ELEMENT);
 			}
 		}

 		private void writeArtifacts(Set artifactDescriptors) {
 			start(ARTIFACTS_ELEMENT);
 			attribute(COLLECTION_SIZE_ATTRIBUTE, artifactDescriptors.size());
 			for (Iterator iter = artifactDescriptors.iterator(); iter.hasNext();) {
 				ArtifactDescriptor descriptor = (ArtifactDescriptor) iter.next();
 				IArtifactKey key = descriptor.getArtifactKey();
 				start(ARTIFACT_ELEMENT);
 				attribute(ARTIFACT_CLASSIFIER_ATTRIBUTE, key.getClassifier());
 				attribute(ID_ATTRIBUTE, key.getId());
 				attribute(VERSION_ATTRIBUTE, key.getVersion());
 				writeProcessingSteps(descriptor.getProcessingSteps());
 				writeProperties(descriptor.getProperties());
 				writeProperties(REPOSITORY_PROPERTIES_ELEMENT, descriptor.getRepositoryProperties());
 				end(ARTIFACT_ELEMENT);
 			}
 			end(ARTIFACTS_ELEMENT);
 		}

 		private void writeProcessingSteps(ProcessingStepDescriptor[] processingSteps) {
 			if (processingSteps.length > 0) {
 				start(PROCESSING_STEPS_ELEMENT);
 				attribute(COLLECTION_SIZE_ATTRIBUTE, processingSteps.length);
 				for (int i = 0; i < processingSteps.length; i++) {
 					start(PROCESSING_STEP_ELEMENT);
 					attribute(ID_ATTRIBUTE, processingSteps[i].getProcessorId());
 					attribute(STEP_DATA_ATTRIBUTE, processingSteps[i].getData());
 					attribute(STEP_REQUIRED_ATTRIBUTE, processingSteps[i].isRequired());
 					end(PROCESSING_STEP_ELEMENT);
 				}
 				end(PROCESSING_STEPS_ELEMENT);
 			}
 		}
 	}

 	/*
 	 * Parser for the contents of a SimpleArtifactRepository,
 	 * as written by the Writer class.
 	 */
 	private class Parser extends XMLParser implements XMLConstants {

 		private SimpleArtifactRepository theRepository = null;

 		public Parser(BundleContext context, String bundleId) {
 			super(context, bundleId);
 		}

 		public void parse(File file) throws IOException {
 			parse(new FileInputStream(file));
 		}

 		public synchronized void parse(InputStream stream) throws IOException {
 			this.status = null;
 			try {
 				// TODO: currently not caching the parser since we make no assumptions
 				//		 or restrictions on concurrent parsing
 				getParser();
 				RepositoryHandler repositoryHandler = new RepositoryHandler();
 				xmlReader.setContentHandler(new RepositoryDocHandler(REPOSITORY_ELEMENT, repositoryHandler));
 				xmlReader.parse(new InputSource(stream));
 				if (isValidXML()) {
 					theRepository = repositoryHandler.getRepository();
 				}
 			} catch (SAXException e) {
 				throw new IOException(e.getMessage());
 			} catch (ParserConfigurationException e) {
 				throw new IOException(e.getMessage());
 			} finally {
 				stream.close();
 			}
 		}

 		public SimpleArtifactRepository getRepository() {
 			return theRepository;
 		}

 		protected Object getRootObject() {
 			return theRepository;
 		}

 		private final class RepositoryDocHandler extends DocHandler {

 			public RepositoryDocHandler(String rootName, RootHandler rootHandler) {
 				super(rootName, rootHandler);
 			}

 			public void processingInstruction(String target, String data) throws SAXException {
 				if (PI_REPOSITORY_TARGET.equals(target)) {
 					// TODO: should the root handler be constructed based on class
 					// 		 via an extension registry mechanism?
 					// String clazz = extractPIClass(data);
 					// TODO: version tolerance by extension
 					Version repositoryVersion = extractPIVersion(target, data);
 					if (!XML_TOLERANCE.isIncluded(repositoryVersion)) {
 						throw new SAXException(NLS.bind(Messages.io_incompatibleVersion, repositoryVersion, XML_TOLERANCE));
 					}
 				}
 			}

 		}

 		private final class RepositoryHandler extends RootHandler {

 			private final String[] required = new String[] {NAME_ATTRIBUTE, TYPE_ATTRIBUTE, VERSION_ATTRIBUTE};
 			private final String[] optional = new String[] {DESCRIPTION_ATTRIBUTE, PROVIDER_ATTRIBUTE, VERIFY_SIGNATURE_ATTRIBUTE};

 			private String[] attrValues = new String[required.length + optional.length];

 			private MappingRulesHandler mappingRulesHandler = null;
 			private PropertiesHandler propertiesHandler = null;
 			private ArtifactsHandler artifactsHandler = null;

 			private SimpleArtifactRepository repository = null;

 			public RepositoryHandler() {
 				super();
 			}

 			public SimpleArtifactRepository getRepository() {
 				return repository;
 			}

 			protected void handleRootAttributes(Attributes attributes) {
 				attrValues = parseAttributes(attributes, required, optional);
 				attrValues[2] = checkVersion(REPOSITORY_ELEMENT, VERSION_ATTRIBUTE, attrValues[2]).toString();
 				attrValues[5] = checkBoolean(REPOSITORY_ELEMENT, VERIFY_SIGNATURE_ATTRIBUTE, attrValues[5], false).toString();
 			}

 			public void startElement(String name, Attributes attributes) {
 				if (MAPPING_RULES_ELEMENT.equals(name)) {
 					if (mappingRulesHandler == null) {
 						mappingRulesHandler = new MappingRulesHandler(this, attributes);
 					} else {
 						duplicateElement(this, name, attributes);
 					}
 				} else if (ARTIFACTS_ELEMENT.equals(name)) {
 					if (artifactsHandler == null) {
 						artifactsHandler = new ArtifactsHandler(this, attributes);
 					} else {
 						duplicateElement(this, name, attributes);
 					}
 				} else if (PROPERTIES_ELEMENT.equals(name)) {
 					if (propertiesHandler == null) {
 						propertiesHandler = new PropertiesHandler(this, attributes);
 					} else {
 						duplicateElement(this, name, attributes);
 					}
 				} else {
 					invalidElement(name, attributes);
 				}
 			}

 			protected void finished() {
 				if (isValidXML()) {
 					String[][] mappingRules = (mappingRulesHandler == null ? new String[0][0] //
 							: mappingRulesHandler.getMappingRules());
 					Map properties = (propertiesHandler == null ? new OrderedProperties(0) //
 							: propertiesHandler.getProperties());
 					Set artifacts = (artifactsHandler == null ? new HashSet(0) //
 							: artifactsHandler.getArtifacts());
 					boolean verifySignature = (attrValues[5] == null ? false //
 							: new Boolean(attrValues[5]).booleanValue());
 					repository = new SimpleArtifactRepository(attrValues[0], attrValues[1], attrValues[2], attrValues[3], //
 							attrValues[4], verifySignature, artifacts, mappingRules, properties);
 				}
 			}
 		}

 		protected class MappingRulesHandler extends AbstractHandler {

 			private List mappingRules;

 			public MappingRulesHandler(AbstractHandler parentHandler, Attributes attributes) {
 				super(parentHandler, MAPPING_RULES_ELEMENT);
 				String size = parseOptionalAttribute(attributes, COLLECTION_SIZE_ATTRIBUTE);
 				mappingRules = (size != null ? new ArrayList(new Integer(size).intValue()) : new ArrayList(4));
 			}

 			public String[][] getMappingRules() {
 				String[][] rules = new String[mappingRules.size()][2];
 				for (int index = 0; index < mappingRules.size(); index++) {
 					String[] ruleAttributes = (String[]) mappingRules.get(index);
 					rules[index] = ruleAttributes;
 				}
 				return rules;
 			}

 			public void startElement(String name, Attributes attributes) {
 				if (name.equals(MAPPING_RULE_ELEMENT)) {
 					new MappingRuleHandler(this, attributes, mappingRules);
 				} else {
 					invalidElement(name, attributes);
 				}
 			}
 		}

 		protected class MappingRuleHandler extends AbstractHandler {

 			private final String[] required = new String[] {MAPPING_RULE_FILTER_ATTRIBUTE, MAPPING_RULE_OUTPUT_ATTRIBUTE};

 			public MappingRuleHandler(AbstractHandler parentHandler, Attributes attributes, List mappingRules) {
 				super(parentHandler, MAPPING_RULE_ELEMENT);
 				mappingRules.add(parseRequiredAttributes(attributes, required));
 			}

 			public void startElement(String name, Attributes attributes) {
 				invalidElement(name, attributes);
 			}
 		}

 		protected class ArtifactsHandler extends AbstractHandler {

 			private Set artifacts;

 			public ArtifactsHandler(AbstractHandler parentHandler, Attributes attributes) {
 				super(parentHandler, ARTIFACTS_ELEMENT);
 				String size = parseOptionalAttribute(attributes, COLLECTION_SIZE_ATTRIBUTE);
 				artifacts = (size != null ? new LinkedHashSet(new Integer(size).intValue()) : new LinkedHashSet(4));
 			}

 			public Set getArtifacts() {
 				return artifacts;
 			}

 			public void startElement(String name, Attributes attributes) {
 				if (name.equals(ARTIFACT_ELEMENT)) {
 					new ArtifactHandler(this, attributes, artifacts);
 				} else {
 					invalidElement(name, attributes);
 				}
 			}
 		}

 		protected class ArtifactHandler extends AbstractHandler {

 			private final String[] required = new String[] {ARTIFACT_CLASSIFIER_ATTRIBUTE, ID_ATTRIBUTE, VERSION_ATTRIBUTE};

 			private Set artifacts;
 			ArtifactDescriptor currentArtifact = null;

 			private PropertiesHandler propertiesHandler = null;
 			private PropertiesHandler repositoryPropertiesHandler = null;
 			private ProcessingStepsHandler processingStepsHandler = null;

 			public ArtifactHandler(AbstractHandler parentHandler, Attributes attributes, Set artifacts) {
 				super(parentHandler, ARTIFACT_ELEMENT);
 				this.artifacts = artifacts;
 				String[] values = parseRequiredAttributes(attributes, required);
 				Version version = checkVersion(ARTIFACT_ELEMENT, VERSION_ATTRIBUTE, values[2]);
 				// TODO: resolve access restriction on ArtifactKey construction
 				currentArtifact = new ArtifactDescriptor(new ArtifactKey(values[0], values[1], version));
 			}

 			public ArtifactDescriptor getArtifact() {
 				return currentArtifact;
 			}

 			public void startElement(String name, Attributes attributes) {
 				if (PROCESSING_STEPS_ELEMENT.equals(name)) {
 					if (processingStepsHandler == null) {
 						processingStepsHandler = new ProcessingStepsHandler(this, attributes);
 					} else {
 						duplicateElement(this, name, attributes);
 					}
 				} else if (PROPERTIES_ELEMENT.equals(name)) {
 					if (propertiesHandler == null) {
 						propertiesHandler = new PropertiesHandler(this, attributes);
 					} else {
 						duplicateElement(this, name, attributes);
 					}
 				} else if (REPOSITORY_PROPERTIES_ELEMENT.equals(name)) {
 					if (repositoryPropertiesHandler == null) {
 						repositoryPropertiesHandler = new PropertiesHandler(this, attributes);
 					} else {
 						duplicateElement(this, name, attributes);
 					}
 				} else {
 					invalidElement(name, attributes);
 				}
 			}

 			protected void finished() {
 				if (isValidXML() && currentArtifact != null) {
 					Map properties = (propertiesHandler == null ? new OrderedProperties(0) : propertiesHandler.getProperties());
 					currentArtifact.addProperties(properties);

 					properties = (repositoryPropertiesHandler == null ? new OrderedProperties(0) : repositoryPropertiesHandler.getProperties());
 					currentArtifact.addRepositoryProperties(properties);

 					ProcessingStepDescriptor[] processingSteps = (processingStepsHandler == null ? new ProcessingStepDescriptor[0] //
 							: processingStepsHandler.getProcessingSteps());
 					currentArtifact.setProcessingSteps(processingSteps);
 					artifacts.add(currentArtifact);
 				}
 			}
 		}

 		protected class ProcessingStepsHandler extends AbstractHandler {

 			private List processingSteps;

 			public ProcessingStepsHandler(AbstractHandler parentHandler, Attributes attributes) {
 				super(parentHandler, PROCESSING_STEPS_ELEMENT);
 				String size = parseOptionalAttribute(attributes, COLLECTION_SIZE_ATTRIBUTE);
 				processingSteps = (size != null ? new ArrayList(new Integer(size).intValue()) : new ArrayList(4));
 			}

 			public ProcessingStepDescriptor[] getProcessingSteps() {
 				return (ProcessingStepDescriptor[]) processingSteps.toArray(new ProcessingStepDescriptor[processingSteps.size()]);
 			}

 			public void startElement(String name, Attributes attributes) {
 				if (name.equals(PROCESSING_STEP_ELEMENT)) {
 					new ProcessingStepHandler(this, attributes, processingSteps);
 				} else {
 					invalidElement(name, attributes);
 				}
 			}
 		}

 		protected class ProcessingStepHandler extends AbstractHandler {

 			private final String[] required = new String[] {ID_ATTRIBUTE, STEP_REQUIRED_ATTRIBUTE};
 			private final String[] optional = new String[] {STEP_DATA_ATTRIBUTE};

 			public ProcessingStepHandler(AbstractHandler parentHandler, Attributes attributes, List processingSteps) {
 				super(parentHandler, PROCESSING_STEP_ELEMENT);
 				String[] attributeValues = parseAttributes(attributes, required, optional);
 				processingSteps.add(new ProcessingStepDescriptor(attributeValues[0], attributeValues[1], checkBoolean(PROCESSING_STEP_ELEMENT, STEP_REQUIRED_ATTRIBUTE, attributeValues[2]).booleanValue()));
 			}

 			public void startElement(String name, Attributes attributes) {
 				invalidElement(name, attributes);
 			}
 		}

 		protected String getErrorMessage() {
 			return Messages.io_parseError;
 		}

 		public String toString() {
 			// TODO:
 			return null;
 		}

 	}

 }
	/*******************************************************************************
	* Copyright (c) 2007, 2008 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.equinox.internal.p2.artifact.repository.simple;

	import java.io.*;
	import java.net.URL;
	import java.util.*;
	import javax.xml.parsers.ParserConfigurationException;
	import org.eclipse.core.runtime.*;
	import org.eclipse.equinox.internal.p2.artifact.repository.Activator;
	import org.eclipse.equinox.internal.p2.artifact.repository.Messages;
	import org.eclipse.equinox.internal.p2.core.helpers.LogHelper;
	import org.eclipse.equinox.internal.p2.core.helpers.OrderedProperties;
	import org.eclipse.equinox.internal.p2.metadata.ArtifactKey;
	import org.eclipse.equinox.internal.p2.persistence.XMLParser;
	import org.eclipse.equinox.internal.p2.persistence.XMLWriter;
	import org.eclipse.equinox.internal.provisional.p2.artifact.repository.ArtifactDescriptor;
	import org.eclipse.equinox.internal.provisional.p2.artifact.repository.IArtifactRepository;
	import org.eclipse.equinox.internal.provisional.p2.artifact.repository.processing.ProcessingStepDescriptor;
	import org.eclipse.equinox.internal.provisional.p2.core.ProvisionException;
	import org.eclipse.equinox.internal.provisional.p2.metadata.IArtifactKey;
	import org.eclipse.osgi.service.resolver.VersionRange;
	import org.eclipse.osgi.util.NLS;
	import org.osgi.framework.BundleContext;
	import org.osgi.framework.Version;
	import org.xml.sax.*;

	/**
	* This class reads and writes artifact repository metadata
	* (e.g. table of contents files);
	*
	* This class is not used for reading or writing the actual artifacts.
	*/

	// TODO: Should a registration/factory mechanism be supported
	// for getting a repository reader/writer given a repository type
	public class SimpleArtifactRepositoryIO {

	/**
	* Writes the given artifact repository to the stream.
	* This method performs buffering, and closes the stream when finished.
	*/
	public void write(SimpleArtifactRepository repository, OutputStream output) {
	OutputStream bufferedOutput = null;
	try {
	try {
	bufferedOutput = new BufferedOutputStream(output);
	Writer repositoryWriter = new Writer(bufferedOutput);
	repositoryWriter.write(repository);
	} finally {
	if (bufferedOutput != null) {
	bufferedOutput.close();
	}
	}
	} catch (IOException ioe) {
	// TODO shouldn't this throw a core exception?
	ioe.printStackTrace();
	}
	}

	/**
	* Reads the artifact repository from the given stream,
	* and returns the contained array of abstract artifact repositories.
	*
	* This method performs buffering, and closes the stream when finished.
	*/
	public IArtifactRepository read(URL location, InputStream input, IProgressMonitor monitor) throws ProvisionException {
	BufferedInputStream bufferedInput = null;
	try {
	try {
	bufferedInput = new BufferedInputStream(input);
	Parser repositoryParser = new Parser(Activator.getContext(), Activator.ID);
	repositoryParser.parse(input);
	IStatus result = repositoryParser.getStatus();
	switch (result.getSeverity()) {
	case IStatus.CANCEL :
	throw new OperationCanceledException();
	case IStatus.ERROR :
	throw new ProvisionException(result);
	case IStatus.WARNING :
	case IStatus.INFO :
	LogHelper.log(result);
	}
	return repositoryParser.getRepository();
	} finally {
	if (bufferedInput != null)
	bufferedInput.close();
	}
	} catch (IOException ioe) {
	String msg = NLS.bind(Messages.io_failedRead, location);
	throw new ProvisionException(new Status(IStatus.ERROR, Activator.ID, ProvisionException.REPOSITORY_FAILED_READ, msg, ioe));
	}
	}

	private interface XMLConstants extends org.eclipse.equinox.internal.p2.persistence.XMLConstants {

	// Constants defining the structure of the XML for a SimpleArtifactRepository

	// A format version number for simple artifact repository XML.
	public static final Version CURRENT_VERSION = new Version(1, 0, 0);
	public static final VersionRange XML_TOLERANCE = new VersionRange(CURRENT_VERSION, true, new Version(2, 0, 0), false);

	// Constants for processing instructions
	public static final String PI_REPOSITORY_TARGET = "artifactRepository"; //$NON-NLS-1$
	public static XMLWriter.ProcessingInstruction[] PI_DEFAULTS = new XMLWriter.ProcessingInstruction[] {XMLWriter.ProcessingInstruction.makeClassVersionInstruction(PI_REPOSITORY_TARGET, SimpleArtifactRepository.class, CURRENT_VERSION)};

	// Constants for artifact repository elements
	public static final String REPOSITORY_ELEMENT = "repository"; //$NON-NLS-1$
	public static final String REPOSITORY_PROPERTIES_ELEMENT = "repositoryProperties"; //$NON-NLS-1$
	public static final String MAPPING_RULES_ELEMENT = "mappings"; //$NON-NLS-1$
	public static final String MAPPING_RULE_ELEMENT = "rule"; //$NON-NLS-1$
	public static final String ARTIFACTS_ELEMENT = "artifacts"; //$NON-NLS-1$
	public static final String ARTIFACT_ELEMENT = "artifact"; //$NON-NLS-1$
	public static final String PROCESSING_STEPS_ELEMENT = "processing"; //$NON-NLS-1$
	public static final String PROCESSING_STEP_ELEMENT = "step"; //$NON-NLS-1$

	// Constants for attributes of artifact repository elements
	public static final String VERIFY_SIGNATURE_ATTRIBUTE = "verify"; //$NON-NLS-1$

	public static final String MAPPING_RULE_FILTER_ATTRIBUTE = "filter"; //$NON-NLS-1$
	public static final String MAPPING_RULE_OUTPUT_ATTRIBUTE = "output"; //$NON-NLS-1$

	public static final String ARTIFACT_CLASSIFIER_ATTRIBUTE = CLASSIFIER_ATTRIBUTE;

	public static final String STEP_DATA_ATTRIBUTE = "data"; //$NON-NLS-1$
	public static final String STEP_REQUIRED_ATTRIBUTE = "required"; //$NON-NLS-1$
	}

	// XML writer for a SimpleArtifactRepository
	protected class Writer extends XMLWriter implements XMLConstants {

	public Writer(OutputStream output) throws IOException {
	super(output, PI_DEFAULTS);
	}

	/**
	* Write the given artifact repository to the output stream.
	*/
	public void write(SimpleArtifactRepository repository) {
	start(REPOSITORY_ELEMENT);
	attribute(NAME_ATTRIBUTE, repository.getName());
	attribute(TYPE_ATTRIBUTE, repository.getType());
	attribute(VERSION_ATTRIBUTE, repository.getVersion());
	attributeOptional(PROVIDER_ATTRIBUTE, repository.getProvider());
	attributeOptional(DESCRIPTION_ATTRIBUTE, repository.getDescription()); // TODO: could be cdata?
	attribute(VERIFY_SIGNATURE_ATTRIBUTE, repository.getSignatureVerification(), false);

	writeProperties(repository.getProperties());
	writeMappingRules(repository.getRules());
	writeArtifacts(repository.getDescriptors());

	end(REPOSITORY_ELEMENT);
	flush();
	}

	private void writeMappingRules(String[][] rules) {
	if (rules.length > 0) {
	start(MAPPING_RULES_ELEMENT);
	attribute(COLLECTION_SIZE_ATTRIBUTE, rules.length);
	for (int i = 0; i < rules.length; i++) {
	start(MAPPING_RULE_ELEMENT);
	attribute(MAPPING_RULE_FILTER_ATTRIBUTE, rules[i][0]);
	attribute(MAPPING_RULE_OUTPUT_ATTRIBUTE, rules[i][1]);
	end(MAPPING_RULE_ELEMENT);
	}
	end(MAPPING_RULES_ELEMENT);
	}
	}

	private void writeArtifacts(Set artifactDescriptors) {
	start(ARTIFACTS_ELEMENT);
	attribute(COLLECTION_SIZE_ATTRIBUTE, artifactDescriptors.size());
	for (Iterator iter = artifactDescriptors.iterator(); iter.hasNext();) {
	ArtifactDescriptor descriptor = (ArtifactDescriptor) iter.next();
	IArtifactKey key = descriptor.getArtifactKey();
	start(ARTIFACT_ELEMENT);
	attribute(ARTIFACT_CLASSIFIER_ATTRIBUTE, key.getClassifier());
	attribute(ID_ATTRIBUTE, key.getId());
	attribute(VERSION_ATTRIBUTE, key.getVersion());
	writeProcessingSteps(descriptor.getProcessingSteps());
	writeProperties(descriptor.getProperties());
	writeProperties(REPOSITORY_PROPERTIES_ELEMENT, descriptor.getRepositoryProperties());
	end(ARTIFACT_ELEMENT);
	}
	end(ARTIFACTS_ELEMENT);
	}

	private void writeProcessingSteps(ProcessingStepDescriptor[] processingSteps) {
	if (processingSteps.length > 0) {
	start(PROCESSING_STEPS_ELEMENT);
	attribute(COLLECTION_SIZE_ATTRIBUTE, processingSteps.length);
	for (int i = 0; i < processingSteps.length; i++) {
	start(PROCESSING_STEP_ELEMENT);
	attribute(ID_ATTRIBUTE, processingSteps[i].getProcessorId());
	attribute(STEP_DATA_ATTRIBUTE, processingSteps[i].getData());
	attribute(STEP_REQUIRED_ATTRIBUTE, processingSteps[i].isRequired());
	end(PROCESSING_STEP_ELEMENT);
	}
	end(PROCESSING_STEPS_ELEMENT);
	}
	}
	}

	/*
	* Parser for the contents of a SimpleArtifactRepository,
	* as written by the Writer class.
	*/
	private class Parser extends XMLParser implements XMLConstants {

	private SimpleArtifactRepository theRepository = null;

	public Parser(BundleContext context, String bundleId) {
	super(context, bundleId);
	}

	public void parse(File file) throws IOException {
	parse(new FileInputStream(file));
	}

	public synchronized void parse(InputStream stream) throws IOException {
	this.status = null;
	try {
	// TODO: currently not caching the parser since we make no assumptions
	// or restrictions on concurrent parsing
	getParser();
	RepositoryHandler repositoryHandler = new RepositoryHandler();
	xmlReader.setContentHandler(new RepositoryDocHandler(REPOSITORY_ELEMENT, repositoryHandler));
	xmlReader.parse(new InputSource(stream));
	if (isValidXML()) {
	theRepository = repositoryHandler.getRepository();
	}
	} catch (SAXException e) {
	throw new IOException(e.getMessage());
	} catch (ParserConfigurationException e) {
	throw new IOException(e.getMessage());
	} finally {
	stream.close();
	}
	}

	public SimpleArtifactRepository getRepository() {
	return theRepository;
	}

	protected Object getRootObject() {
	return theRepository;
	}

	private final class RepositoryDocHandler extends DocHandler {

	public RepositoryDocHandler(String rootName, RootHandler rootHandler) {
	super(rootName, rootHandler);
	}

	public void processingInstruction(String target, String data) throws SAXException {
	if (PI_REPOSITORY_TARGET.equals(target)) {
	// TODO: should the root handler be constructed based on class
	// via an extension registry mechanism?
	// String clazz = extractPIClass(data);
	// TODO: version tolerance by extension
	Version repositoryVersion = extractPIVersion(target, data);
	if (!XML_TOLERANCE.isIncluded(repositoryVersion)) {
	throw new SAXException(NLS.bind(Messages.io_incompatibleVersion, repositoryVersion, XML_TOLERANCE));
	}
	}
	}

	}

	private final class RepositoryHandler extends RootHandler {

	private final String[] required = new String[] {NAME_ATTRIBUTE, TYPE_ATTRIBUTE, VERSION_ATTRIBUTE};
	private final String[] optional = new String[] {DESCRIPTION_ATTRIBUTE, PROVIDER_ATTRIBUTE, VERIFY_SIGNATURE_ATTRIBUTE};

	private String[] attrValues = new String[required.length + optional.length];

	private MappingRulesHandler mappingRulesHandler = null;
	private PropertiesHandler propertiesHandler = null;
	private ArtifactsHandler artifactsHandler = null;

	private SimpleArtifactRepository repository = null;

	public RepositoryHandler() {
	super();
	}

	public SimpleArtifactRepository getRepository() {
	return repository;
	}

	protected void handleRootAttributes(Attributes attributes) {
	attrValues = parseAttributes(attributes, required, optional);
	attrValues[2] = checkVersion(REPOSITORY_ELEMENT, VERSION_ATTRIBUTE, attrValues[2]).toString();
	attrValues[5] = checkBoolean(REPOSITORY_ELEMENT, VERIFY_SIGNATURE_ATTRIBUTE, attrValues[5], false).toString();
	}

	public void startElement(String name, Attributes attributes) {
	if (MAPPING_RULES_ELEMENT.equals(name)) {
	if (mappingRulesHandler == null) {
	mappingRulesHandler = new MappingRulesHandler(this, attributes);
	} else {
	duplicateElement(this, name, attributes);
	}
	} else if (ARTIFACTS_ELEMENT.equals(name)) {
	if (artifactsHandler == null) {
	artifactsHandler = new ArtifactsHandler(this, attributes);
	} else {
	duplicateElement(this, name, attributes);
	}
	} else if (PROPERTIES_ELEMENT.equals(name)) {
	if (propertiesHandler == null) {
	propertiesHandler = new PropertiesHandler(this, attributes);
	} else {
	duplicateElement(this, name, attributes);
	}
	} else {
	invalidElement(name, attributes);
	}
	}

	protected void finished() {
	if (isValidXML()) {
	String[][] mappingRules = (mappingRulesHandler == null ? new String[0][0] //
	: mappingRulesHandler.getMappingRules());
	Map properties = (propertiesHandler == null ? new OrderedProperties(0) //
	: propertiesHandler.getProperties());
	Set artifacts = (artifactsHandler == null ? new HashSet(0) //
	: artifactsHandler.getArtifacts());
	boolean verifySignature = (attrValues[5] == null ? false //
	: new Boolean(attrValues[5]).booleanValue());
	repository = new SimpleArtifactRepository(attrValues[0], attrValues[1], attrValues[2], attrValues[3], //
	attrValues[4], verifySignature, artifacts, mappingRules, properties);
	}
	}
	}

	protected class MappingRulesHandler extends AbstractHandler {

	private List mappingRules;

	public MappingRulesHandler(AbstractHandler parentHandler, Attributes attributes) {
	super(parentHandler, MAPPING_RULES_ELEMENT);
	String size = parseOptionalAttribute(attributes, COLLECTION_SIZE_ATTRIBUTE);
	mappingRules = (size != null ? new ArrayList(new Integer(size).intValue()) : new ArrayList(4));
	}

	public String[][] getMappingRules() {
	String[][] rules = new String[mappingRules.size()][2];
	for (int index = 0; index < mappingRules.size(); index++) {
	String[] ruleAttributes = (String[]) mappingRules.get(index);
	rules[index] = ruleAttributes;
	}
	return rules;
	}

	public void startElement(String name, Attributes attributes) {
	if (name.equals(MAPPING_RULE_ELEMENT)) {
	new MappingRuleHandler(this, attributes, mappingRules);
	} else {
	invalidElement(name, attributes);
	}
	}
	}

	protected class MappingRuleHandler extends AbstractHandler {

	private final String[] required = new String[] {MAPPING_RULE_FILTER_ATTRIBUTE, MAPPING_RULE_OUTPUT_ATTRIBUTE};

	public MappingRuleHandler(AbstractHandler parentHandler, Attributes attributes, List mappingRules) {
	super(parentHandler, MAPPING_RULE_ELEMENT);
	mappingRules.add(parseRequiredAttributes(attributes, required));
	}

	public void startElement(String name, Attributes attributes) {
	invalidElement(name, attributes);
	}
	}

	protected class ArtifactsHandler extends AbstractHandler {

	private Set artifacts;

	public ArtifactsHandler(AbstractHandler parentHandler, Attributes attributes) {
	super(parentHandler, ARTIFACTS_ELEMENT);
	String size = parseOptionalAttribute(attributes, COLLECTION_SIZE_ATTRIBUTE);
	artifacts = (size != null ? new LinkedHashSet(new Integer(size).intValue()) : new LinkedHashSet(4));
	}

	public Set getArtifacts() {
	return artifacts;
	}

	public void startElement(String name, Attributes attributes) {
	if (name.equals(ARTIFACT_ELEMENT)) {
	new ArtifactHandler(this, attributes, artifacts);
	} else {
	invalidElement(name, attributes);
	}
	}
	}

	protected class ArtifactHandler extends AbstractHandler {

	private final String[] required = new String[] {ARTIFACT_CLASSIFIER_ATTRIBUTE, ID_ATTRIBUTE, VERSION_ATTRIBUTE};

	private Set artifacts;
	ArtifactDescriptor currentArtifact = null;

	private PropertiesHandler propertiesHandler = null;
	private PropertiesHandler repositoryPropertiesHandler = null;
	private ProcessingStepsHandler processingStepsHandler = null;

	public ArtifactHandler(AbstractHandler parentHandler, Attributes attributes, Set artifacts) {
	super(parentHandler, ARTIFACT_ELEMENT);
	this.artifacts = artifacts;
	String[] values = parseRequiredAttributes(attributes, required);
	Version version = checkVersion(ARTIFACT_ELEMENT, VERSION_ATTRIBUTE, values[2]);
	// TODO: resolve access restriction on ArtifactKey construction
	currentArtifact = new ArtifactDescriptor(new ArtifactKey(values[0], values[1], version));
	}

	public ArtifactDescriptor getArtifact() {
	return currentArtifact;
	}

	public void startElement(String name, Attributes attributes) {
	if (PROCESSING_STEPS_ELEMENT.equals(name)) {
	if (processingStepsHandler == null) {
	processingStepsHandler = new ProcessingStepsHandler(this, attributes);
	} else {
	duplicateElement(this, name, attributes);
	}
	} else if (PROPERTIES_ELEMENT.equals(name)) {
	if (propertiesHandler == null) {
	propertiesHandler = new PropertiesHandler(this, attributes);
	} else {
	duplicateElement(this, name, attributes);
	}
	} else if (REPOSITORY_PROPERTIES_ELEMENT.equals(name)) {
	if (repositoryPropertiesHandler == null) {
	repositoryPropertiesHandler = new PropertiesHandler(this, attributes);
	} else {
	duplicateElement(this, name, attributes);
	}
	} else {
	invalidElement(name, attributes);
	}
	}

	protected void finished() {
	if (isValidXML() && currentArtifact != null) {
	Map properties = (propertiesHandler == null ? new OrderedProperties(0) : propertiesHandler.getProperties());
	currentArtifact.addProperties(properties);

	properties = (repositoryPropertiesHandler == null ? new OrderedProperties(0) : repositoryPropertiesHandler.getProperties());
	currentArtifact.addRepositoryProperties(properties);

	ProcessingStepDescriptor[] processingSteps = (processingStepsHandler == null ? new ProcessingStepDescriptor[0] //
	: processingStepsHandler.getProcessingSteps());
	currentArtifact.setProcessingSteps(processingSteps);
	artifacts.add(currentArtifact);
	}
	}
	}

	protected class ProcessingStepsHandler extends AbstractHandler {

	private List processingSteps;

	public ProcessingStepsHandler(AbstractHandler parentHandler, Attributes attributes) {
	super(parentHandler, PROCESSING_STEPS_ELEMENT);
	String size = parseOptionalAttribute(attributes, COLLECTION_SIZE_ATTRIBUTE);
	processingSteps = (size != null ? new ArrayList(new Integer(size).intValue()) : new ArrayList(4));
	}

	public ProcessingStepDescriptor[] getProcessingSteps() {
	return (ProcessingStepDescriptor[]) processingSteps.toArray(new ProcessingStepDescriptor[processingSteps.size()]);
	}

	public void startElement(String name, Attributes attributes) {
	if (name.equals(PROCESSING_STEP_ELEMENT)) {
	new ProcessingStepHandler(this, attributes, processingSteps);
	} else {
	invalidElement(name, attributes);
	}
	}
	}

	protected class ProcessingStepHandler extends AbstractHandler {

	private final String[] required = new String[] {ID_ATTRIBUTE, STEP_REQUIRED_ATTRIBUTE};
	private final String[] optional = new String[] {STEP_DATA_ATTRIBUTE};

	public ProcessingStepHandler(AbstractHandler parentHandler, Attributes attributes, List processingSteps) {
	super(parentHandler, PROCESSING_STEP_ELEMENT);
	String[] attributeValues = parseAttributes(attributes, required, optional);
	processingSteps.add(new ProcessingStepDescriptor(attributeValues[0], attributeValues[1], checkBoolean(PROCESSING_STEP_ELEMENT, STEP_REQUIRED_ATTRIBUTE, attributeValues[2]).booleanValue()));
	}

	public void startElement(String name, Attributes attributes) {
	invalidElement(name, attributes);
	}
	}

	protected String getErrorMessage() {
	return Messages.io_parseError;
	}

	public String toString() {
	// TODO:
	return null;
	}

	}

	}