Copyright (c) 2000, 2015 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
    James Blackburn (Broadcom Corp.) - ongoing development
    Lars Vogel  - Bug 473427
/*******************************************************************************
 * Copyright (c) 2000, 2015 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     James Blackburn (Broadcom Corp.) - ongoing development
 *     Lars Vogel <Lars.Vogel@vogella.com> - Bug 473427
 *******************************************************************************/
package org.eclipse.core.internal.resources;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import javax.xml.parsers.*;
import org.eclipse.core.internal.localstore.SafeFileInputStream;
import org.eclipse.core.internal.utils.Messages;
import org.eclipse.core.internal.utils.Policy;
import org.eclipse.core.resources.IResourceStatus;
import org.eclipse.core.runtime.IPath;
import org.eclipse.osgi.util.NLS;
import org.w3c.dom.*;
import org.xml.sax.SAXException;

This class contains legacy code only.  It is being used to read workspace
descriptions which are obsolete.
/**
 * This class contains legacy code only.  It is being used to read workspace
 * descriptions which are obsolete.
 */
public class WorkspaceDescriptionReader implements IModelObjectConstants {
	
constants /** constants */
	protected static final String[] EMPTY_STRING_ARRAY = new String[0];

	public WorkspaceDescriptionReader() {
		super();
	}

	protected String getString(Node target, String tagName) {
		Node node = searchNode(target, tagName);
		return node != null ? (node.getFirstChild() == null ? null : node.getFirstChild().getNodeValue()) : null;
	}

	protected String[] getStrings(Node target) {
		if (target == null)
			return null;
		NodeList list = target.getChildNodes();
		if (list.getLength() == 0)
			return EMPTY_STRING_ARRAY;
		List<Object> result = new ArrayList<>(list.getLength());
		for (int i = 0; i < list.getLength(); i++) {
			Node node = list.item(i);
			if (node.getNodeType() == Node.ELEMENT_NODE)
				result.add(read(node.getChildNodes().item(0)));
		}
		return result.toArray(new String[result.size()]);
	}

	
A value was discovered in the workspace description file that was not a number.
Log the exception.
/**
	 * A value was discovered in the workspace description file that was not a number.
	 * Log the exception.
	 */
	private void logNumberFormatException(String value, NumberFormatException e) {
		String msg = NLS.bind(Messages.resources_readWorkspaceMetaValue, value);
		Policy.log(new ResourceStatus(IResourceStatus.FAILED_READ_METADATA, null, msg, e));
	}

	public Object read(InputStream input) {
		try {
			DocumentBuilder parser = DocumentBuilderFactory.newInstance().newDocumentBuilder();
			Document document = parser.parse(input);
			return read(document.getFirstChild());
		} catch (IOException | SAXException | ParserConfigurationException e) {
			// ignore
		}
		return null;
	}

	public Object read(IPath location, IPath tempLocation) throws IOException {
		try (
			SafeFileInputStream file = new SafeFileInputStream(location.toOSString(), tempLocation.toOSString());
		) {
			return read(file);
		}
	}

	protected Object read(Node node) {
		if (node == null)
			return null;
		switch (node.getNodeType()) {
			case Node.ELEMENT_NODE :
				if (node.getNodeName().equals(WORKSPACE_DESCRIPTION))
					return readWorkspaceDescription(node);
			case Node.TEXT_NODE :
				String value = node.getNodeValue();
				return value == null ? null : value.trim();
			default :
				return node.toString();
		}
	}

	
read (String, String) hashtables
/**
	 * read (String, String) hashtables
	 */
	protected WorkspaceDescription readWorkspaceDescription(Node node) {
		// get values
		String name = getString(node, NAME);
		String autobuild = getString(node, AUTOBUILD);
		String snapshotInterval = getString(node, SNAPSHOT_INTERVAL);
		String applyFileStatePolicy = getString(node, APPLY_FILE_STATE_POLICY);
		String fileStateLongevity = getString(node, FILE_STATE_LONGEVITY);
		String maxFileStateSize = getString(node, MAX_FILE_STATE_SIZE);
		String maxFileStates = getString(node, MAX_FILE_STATES);
		String[] buildOrder = getStrings(searchNode(node, BUILD_ORDER));

		// build instance
		//invalid values are skipped and defaults are used instead
		WorkspaceDescription description = new WorkspaceDescription(name);
		if (autobuild != null)
			//if in doubt (value is corrupt) we want autobuild on
			description.setAutoBuilding(!autobuild.equals(Integer.toString(0)));
		if (applyFileStatePolicy != null)
			//if in doubt (value is corrupt) we want applyFileLimits on
			description.setApplyFileStatePolicy(!applyFileStatePolicy.equals(Integer.toString(0)));
		try {
			if (fileStateLongevity != null)
				description.setFileStateLongevity(Long.parseLong(fileStateLongevity));
		} catch (NumberFormatException e) {
			logNumberFormatException(fileStateLongevity, e);
		}
		try {
			if (maxFileStateSize != null)
				description.setMaxFileStateSize(Long.parseLong(maxFileStateSize));
		} catch (NumberFormatException e) {
			logNumberFormatException(maxFileStateSize, e);
		}
		try {
			if (maxFileStates != null)
				description.setMaxFileStates(Integer.parseInt(maxFileStates));
		} catch (NumberFormatException e) {
			logNumberFormatException(maxFileStates, e);
		}
		if (buildOrder != null)
			description.internalSetBuildOrder(buildOrder);
		try {
			if (snapshotInterval != null)
				description.setSnapshotInterval(Long.parseLong(snapshotInterval));
		} catch (NumberFormatException e) {
			logNumberFormatException(snapshotInterval, e);
		}
		return description;
	}

	protected Node searchNode(Node target, String tagName) {
		NodeList list = target.getChildNodes();
		for (int i = 0; i < list.getLength(); i++) {
			if (list.item(i).getNodeName().equals(tagName))
				return list.item(i);
		}
		return null;
	}
}