bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/ChooseWorkspaceData.java - platform/eclipse.platform.ui - Git at Google

 /*******************************************************************************
  * Copyright (c) 2004, 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.ui.internal.ide;

 import java.io.File;
 import java.io.FileReader;
 import java.io.IOException;
 import java.io.Reader;
 import java.net.URL;
 import java.util.StringTokenizer;

 import org.eclipse.core.runtime.Path;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.core.runtime.preferences.ConfigurationScope;
 import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.osgi.service.datalocation.Location;
 import org.eclipse.ui.IMemento;
 import org.eclipse.ui.WorkbenchException;
 import org.eclipse.ui.XMLMemento;
 import org.eclipse.ui.ide.IDE;
 import org.eclipse.ui.preferences.ScopedPreferenceStore;
 import org.osgi.service.prefs.BackingStoreException;
 import org.osgi.service.prefs.Preferences;

 /**
  * This class stores the information behind the "Launch Workspace" dialog. The
  * class is able to read and write itself to a well known configuration file.
  */
 public class ChooseWorkspaceData {
     /**
      * The default max length of the recent workspace mru list.
      */
     private static final int RECENT_MAX_LENGTH = 5;

     /**
      * The directory within the config area that will be used for the
      * receiver's persisted data.
      */
     private static final String PERS_FOLDER = "org.eclipse.ui.ide"; //$NON-NLS-1$

     /**
      * The name of the file within the config area that will be used for
      * the recever's persisted data.
      * @see PERS_FOLDER
      */
     private static final String PERS_FILENAME = "recentWorkspaces.xml"; //$NON-NLS-1$

     /**
      * In the past a file was used to store persist these values.  This file was written
      * with this value as its protocol identifier.
      */
     private static final int PERS_ENCODING_VERSION = 1;

     /**
      * This is the first version of the encode/decode protocol that uses the config area
      * preference store for persistence.  The only encoding done is to convert the recent
      * workspace list into a comma-separated list.
      */
     private static final int PERS_ENCODING_VERSION_CONFIG_PREFS = 2;

     private boolean showDialog = true;

     private String initialDefault;

     private String selection;

     private String[] recentWorkspaces;

     // xml tags
     private static interface XML {
         public static final String PROTOCOL = "protocol"; //$NON-NLS-1$

         public static final String VERSION = "version"; //$NON-NLS-1$

         public static final String ALWAYS_ASK = "alwaysAsk"; //$NON-NLS-1$

         public static final String SHOW_DIALOG = "showDialog"; //$NON-NLS-1$

         public static final String WORKSPACE = "workspace"; //$NON-NLS-1$

         public static final String RECENT_WORKSPACES = "recentWorkspaces"; //$NON-NLS-1$

         public static final String MAX_LENGTH = "maxLength"; //$NON-NLS-1$

         public static final String PATH = "path"; //$NON-NLS-1$
     }

     /**
      * Creates a new instance, loading persistent data if its found.
      */
     public ChooseWorkspaceData(String initialDefault) {
         readPersistedData();
         setInitialDefault(initialDefault);
     }

     /**
      * Creates a new instance, loading persistent data if its found.
      */
     public ChooseWorkspaceData(URL instanceUrl) {
         readPersistedData();
         if (instanceUrl != null)
             setInitialDefault(new File(instanceUrl.getFile()).toString());
     }

     /**
      * Return the folder to be used as a default if no other information
      * exists. Does not return null.
      */
     public String getInitialDefault() {
         if (initialDefault == null)
             setInitialDefault(System.getProperty("user.dir") //$NON-NLS-1$
                     + File.separator + "workspace"); //$NON-NLS-1$
         return initialDefault;
     }

     /**
      * Set this data's initialDefault parameter to a properly formatted version
      * of the argument directory string. The proper format is to the platform
      * appropriate separator character without meaningless leading or trailing
      * separator characters.
      */
     private void setInitialDefault(String dir) {
         if (dir == null || dir.length() <= 0) {
             initialDefault = null;
             return;
         }

         dir = new Path(dir).toOSString();
         while (dir.charAt(dir.length() - 1) == File.separatorChar)
             dir = dir.substring(0, dir.length() - 1);
         initialDefault = dir;
     }

     /**
      * Return the currently selected workspace or null if nothing is selected.
      */
     public String getSelection() {
         return selection;
     }

     /**
      * Return the currently selected workspace or null if nothing is selected.
      */
     public boolean getShowDialog() {
         return showDialog;
     }

     /**
      * Return an array of recent workspaces sorted with the most recently used at
      * the start.
      */
     public String[] getRecentWorkspaces() {
         return recentWorkspaces;
     }

     /**
      * The argument workspace has been selected, update the receiver.  Does not
      * persist the new values.
      */
     public void workspaceSelected(String dir) {
         // this just stores the selection, it is not inserted and persisted
         // until the workspace is actually selected
         selection = dir;
     }

     /**
      * Toggle value of the showDialog persistent setting.
      */
     public void toggleShowDialog() {
         showDialog = !showDialog;
     }

     /**
 	 * Update the persistent store. Call this function after the currently
 	 * selected value has been found to be ok.
 	 */
 	public void writePersistedData() {
 		// 1. get config pref node
 		Preferences node = new ConfigurationScope().getNode(IDEWorkbenchPlugin.IDE_WORKBENCH);

 		// 2. get value for showDialog
 		node.putBoolean(
 				IDE.Preferences.SHOW_WORKSPACE_SELECTION_DIALOG,
 				showDialog);

 		// 3. use value of numRecent to create proper length array
 		node.putInt(IDE.Preferences.MAX_RECENT_WORKSPACES,
 				recentWorkspaces.length);

 		// move the new selection to the front of the list
 		if (selection != null) {
 			String oldEntry = recentWorkspaces[0];
 			recentWorkspaces[0] = selection;
 			for (int i = 1; i < recentWorkspaces.length && oldEntry != null; ++i) {
 				if (selection.equals(oldEntry))
 					break;
 				String tmp = recentWorkspaces[i];
 				recentWorkspaces[i] = oldEntry;
 				oldEntry = tmp;
 			}
 		}

 		// 4. store values of recent workspaces into array
 		String encodedRecentWorkspaces = encodeStoredWorkspacePaths(recentWorkspaces);
 		node.put(IDE.Preferences.RECENT_WORKSPACES,
 				encodedRecentWorkspaces);

 		// 5. store the protocol version used to encode the list
 		node.putInt(IDE.Preferences.RECENT_WORKSPACES_PROTOCOL,
 				PERS_ENCODING_VERSION_CONFIG_PREFS);

 		// 6. store the node
 		try {
 			node.flush();
 		} catch (BackingStoreException e) {
 			// do nothing
 		}
 	}

     /**
 	 * Look for and read data that might have been persisted from some previous
 	 * run. Leave the receiver in a default state if no persistent data is
 	 * found.
 	 *
 	 * @return true if a file was successfully read and false otherwise
 	 */
     private boolean readPersistedData_file() {
 	    URL persUrl = null;

 	    Location configLoc = Platform.getConfigurationLocation();
 	    if (configLoc != null)
 	        persUrl = getPersistenceUrl(configLoc.getURL(), false);

 	    try {
 	        // inside try to get the safe default creation in the finally
 	        // clause
 	        if (persUrl == null)
 	            return false;

 	        // E.g.,
 	        //	<launchWorkspaceData>
 	        //		<protocol version="1"/>
 	        //      <alwaysAsk showDialog="1"/>
 	        // 		<recentWorkspaces maxLength="5">
 	        //			<workspace path="C:\eclipse\workspace0"/>
 	        //			<workspace path="C:\eclipse\workspace1"/>
 	        //		</recentWorkspaces>
 	        //	</launchWorkspaceData>

 	        Reader reader = new FileReader(persUrl.getFile());
 	        XMLMemento memento = XMLMemento.createReadRoot(reader);
 	        if (memento == null || !compatibleFileProtocol(memento))
 	            return false;

 	        IMemento alwaysAskTag = memento.getChild(XML.ALWAYS_ASK);
 	        showDialog = alwaysAskTag == null ? true : alwaysAskTag.getInteger(
 	                XML.SHOW_DIALOG).intValue() == 1;

 	        IMemento recent = memento.getChild(XML.RECENT_WORKSPACES);
 	        if (recent == null)
 	            return false;

 	        Integer maxLength = recent.getInteger(XML.MAX_LENGTH);
 	        int max = RECENT_MAX_LENGTH;
 	        if (maxLength != null)
 	            max = maxLength.intValue();

 	        IMemento indices[] = recent.getChildren(XML.WORKSPACE);
 	        if (indices == null || indices.length <= 0)
 	            return false;

 	        // if a user has edited maxLength to be shorter than the listed
 	        // indices, accept the list (its tougher for them to retype a long
 	        // list of paths than to update a max number)
 	        max = Math.max(max, indices.length);

 	        recentWorkspaces = new String[max];
 	        for (int i = 0; i < indices.length; ++i) {
 	            String path = indices[i].getString(XML.PATH);
 	            if (path == null)
 	                break;
 	            recentWorkspaces[i] = path;
 	        }
 	    } catch (IOException e) {
 	        // cannot log because instance area has not been set
 	        return false;
 	    } catch (WorkbenchException e) {
 	        // cannot log because instance area has not been set
 	        return false;
 	    } finally {
 	        // create safe default if needed
 	        if (recentWorkspaces == null)
 	            recentWorkspaces = new String[RECENT_MAX_LENGTH];
 	    }

 	    return true;
 	}

     /**
      * Return the current (persisted) value of the "showDialog on startup"
      * preference. Return the global default if the file cannot be accessed.
      */
     public static boolean getShowDialogValue() {
     	// TODO See the long comment in #readPersistedData -- when the
 		//      transition time is over this method can be changed to
     	//      read the preference directly.

         ChooseWorkspaceData data = new ChooseWorkspaceData(""); //$NON-NLS-1$

         // return either the value in the file or true, which is the global
         // default
         return data.readPersistedData() ? data.showDialog : true;
     }

     /**
 	 * Return the current (persisted) value of the "showDialog on startup"
 	 * preference. Return the global default if the file cannot be accessed.
 	 */
 	public static void setShowDialogValue(boolean showDialog) {
 		// TODO See the long comment in #readPersistedData -- when the
 		//      transition time is over this method can be changed to
 		//      read the preference directly.

 		ChooseWorkspaceData data = new ChooseWorkspaceData(""); //$NON-NLS-1$

 		// update the value and write the new settings
 		data.showDialog = showDialog;
 		data.writePersistedData();
 	}

     /**
 	 * Look in the config area preference store for the list of recently used
 	 * workspaces.
 	 *
 	 * NOTE: During the transition phase the file will be checked if no config
 	 * preferences are found.
 	 *
 	 * @return true if the values were successfully retrieved and false
 	 *         otherwise
 	 */
 	public boolean readPersistedData() {
 		IPreferenceStore store = new ScopedPreferenceStore(
 				new ConfigurationScope(), IDEWorkbenchPlugin.IDE_WORKBENCH);

 		// The old way was to store this information in a file, the new is to
 		// use the configuration area preference store. To help users with the
 		// transition, this code always looks for values in the preference
 		// store; they are used if found. If there aren't any related
 		// preferences, then the file method is used instead. This class always
 		// writes to the preference store, so the fall-back should be needed no
 		// more than once per-user, per-configuration.

 		// This code always sets the value of the protocol to a non-zero value
 		// (currently at 2).  If the value comes back as the default (0), then
 		// none of the preferences were set, revert to the file method.

 		int protocol = store
 				.getInt(IDE.Preferences.RECENT_WORKSPACES_PROTOCOL);
 		if (protocol == IPreferenceStore.INT_DEFAULT_DEFAULT
 				&& readPersistedData_file())
 			return true;

 		// 2. get value for showDialog
 		showDialog = store
 				.getBoolean(IDE.Preferences.SHOW_WORKSPACE_SELECTION_DIALOG);

 		// 3. use value of numRecent to create proper length array
 		int max = store
 				.getInt(IDE.Preferences.MAX_RECENT_WORKSPACES);
 		max = Math.max(max, RECENT_MAX_LENGTH);

 		// 4. load values of recent workspaces into array
 		String workspacePathPref = store
 				.getString(IDE.Preferences.RECENT_WORKSPACES);
 		recentWorkspaces = decodeStoredWorkspacePaths(max, workspacePathPref);

 		return true;
 	}

 	/**
 	 * The the list of recent workspaces must be stored as a string in the preference node.
 	 */
     private static String encodeStoredWorkspacePaths(String[] recent) {
 		StringBuffer buff = new StringBuffer();

 		String path = null;
 		for (int i = 0; i < recent.length; ++i) {
 			if (recent[i] == null)
 				break;

 			if (path != null)
 				buff.append(","); //$NON-NLS-1$

 			path = recent[i];
 			buff.append(path);
 		}

 		return buff.toString();
 	}

 	/**
 	 * The the preference for recent workspaces must be converted from the
 	 * storage string into an array.
 	 */
     private static String[] decodeStoredWorkspacePaths(int max, String prefValue) {
 		String[] paths = new String[max];
 		if (prefValue == null || prefValue.length() <= 0)
 			return paths;

 		StringTokenizer tokenizer = new StringTokenizer(prefValue, ","); //$NON-NLS-1$
 		for (int i = 0; i < paths.length && tokenizer.hasMoreTokens(); ++i)
 			paths[i] = tokenizer.nextToken();

 		return paths;
 	}

     /**
 	 * Return true if the protocol used to encode the argument memento is
 	 * compatible with the receiver's implementation and false otherwise.
 	 */
     private static boolean compatibleFileProtocol(IMemento memento) {
         IMemento protocolMemento = memento.getChild(XML.PROTOCOL);
         if (protocolMemento == null)
             return false;

         Integer version = protocolMemento.getInteger(XML.VERSION);
         return version != null && version.intValue() == PERS_ENCODING_VERSION;
     }

     /**
      * The workspace data is stored in the well known file pointed to by the result
      * of this method.
      * @param create If the directory and file does not exist this parameter
      *               controls whether it will be created.
      * @return An url to the file and null if it does not exist or could not
      *         be created.
      */
     private static URL getPersistenceUrl(URL baseUrl, boolean create) {
         if (baseUrl == null)
             return null;

         try {
             // make sure the directory exists
             URL url = new URL(baseUrl, PERS_FOLDER);
             File dir = new File(url.getFile());
             if (!dir.exists() && (!create || !dir.mkdir()))
                 return null;

             // make sure the file exists
             url = new URL(dir.toURL(), PERS_FILENAME);
             File persFile = new File(url.getFile());
             if (!persFile.exists() && (!create || !persFile.createNewFile()))
                 return null;

             return persFile.toURL();
         } catch (IOException e) {
             // cannot log because instance area has not been set
             return null;
         }
     }
 }
	/*******************************************************************************
	* Copyright (c) 2004, 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.ui.internal.ide;

	import java.io.File;
	import java.io.FileReader;
	import java.io.IOException;
	import java.io.Reader;
	import java.net.URL;
	import java.util.StringTokenizer;

	import org.eclipse.core.runtime.Path;
	import org.eclipse.core.runtime.Platform;
	import org.eclipse.core.runtime.preferences.ConfigurationScope;
	import org.eclipse.jface.preference.IPreferenceStore;
	import org.eclipse.osgi.service.datalocation.Location;
	import org.eclipse.ui.IMemento;
	import org.eclipse.ui.WorkbenchException;
	import org.eclipse.ui.XMLMemento;
	import org.eclipse.ui.ide.IDE;
	import org.eclipse.ui.preferences.ScopedPreferenceStore;
	import org.osgi.service.prefs.BackingStoreException;
	import org.osgi.service.prefs.Preferences;

	/**
	* This class stores the information behind the "Launch Workspace" dialog. The
	* class is able to read and write itself to a well known configuration file.
	*/
	public class ChooseWorkspaceData {
	/**
	* The default max length of the recent workspace mru list.
	*/
	private static final int RECENT_MAX_LENGTH = 5;

	/**
	* The directory within the config area that will be used for the
	* receiver's persisted data.
	*/
	private static final String PERS_FOLDER = "org.eclipse.ui.ide"; //$NON-NLS-1$

	/**
	* The name of the file within the config area that will be used for
	* the recever's persisted data.
	* @see PERS_FOLDER
	*/
	private static final String PERS_FILENAME = "recentWorkspaces.xml"; //$NON-NLS-1$

	/**
	* In the past a file was used to store persist these values. This file was written
	* with this value as its protocol identifier.
	*/
	private static final int PERS_ENCODING_VERSION = 1;

	/**
	* This is the first version of the encode/decode protocol that uses the config area
	* preference store for persistence. The only encoding done is to convert the recent
	* workspace list into a comma-separated list.
	*/
	private static final int PERS_ENCODING_VERSION_CONFIG_PREFS = 2;

	private boolean showDialog = true;

	private String initialDefault;

	private String selection;

	private String[] recentWorkspaces;

	// xml tags
	private static interface XML {
	public static final String PROTOCOL = "protocol"; //$NON-NLS-1$

	public static final String VERSION = "version"; //$NON-NLS-1$

	public static final String ALWAYS_ASK = "alwaysAsk"; //$NON-NLS-1$

	public static final String SHOW_DIALOG = "showDialog"; //$NON-NLS-1$

	public static final String WORKSPACE = "workspace"; //$NON-NLS-1$

	public static final String RECENT_WORKSPACES = "recentWorkspaces"; //$NON-NLS-1$

	public static final String MAX_LENGTH = "maxLength"; //$NON-NLS-1$

	public static final String PATH = "path"; //$NON-NLS-1$
	}

	/**
	* Creates a new instance, loading persistent data if its found.
	*/
	public ChooseWorkspaceData(String initialDefault) {
	readPersistedData();
	setInitialDefault(initialDefault);
	}

	/**
	* Creates a new instance, loading persistent data if its found.
	*/
	public ChooseWorkspaceData(URL instanceUrl) {
	readPersistedData();
	if (instanceUrl != null)
	setInitialDefault(new File(instanceUrl.getFile()).toString());
	}

	/**
	* Return the folder to be used as a default if no other information
	* exists. Does not return null.
	*/
	public String getInitialDefault() {
	if (initialDefault == null)
	setInitialDefault(System.getProperty("user.dir") //$NON-NLS-1$
	+ File.separator + "workspace"); //$NON-NLS-1$
	return initialDefault;
	}

	/**
	* Set this data's initialDefault parameter to a properly formatted version
	* of the argument directory string. The proper format is to the platform
	* appropriate separator character without meaningless leading or trailing
	* separator characters.
	*/
	private void setInitialDefault(String dir) {
	if (dir == null \|\| dir.length() <= 0) {
	initialDefault = null;
	return;
	}

	dir = new Path(dir).toOSString();
	while (dir.charAt(dir.length() - 1) == File.separatorChar)
	dir = dir.substring(0, dir.length() - 1);
	initialDefault = dir;
	}

	/**
	* Return the currently selected workspace or null if nothing is selected.
	*/
	public String getSelection() {
	return selection;
	}

	/**
	* Return the currently selected workspace or null if nothing is selected.
	*/
	public boolean getShowDialog() {
	return showDialog;
	}

	/**
	* Return an array of recent workspaces sorted with the most recently used at
	* the start.
	*/
	public String[] getRecentWorkspaces() {
	return recentWorkspaces;
	}

	/**
	* The argument workspace has been selected, update the receiver. Does not
	* persist the new values.
	*/
	public void workspaceSelected(String dir) {
	// this just stores the selection, it is not inserted and persisted
	// until the workspace is actually selected
	selection = dir;
	}

	/**
	* Toggle value of the showDialog persistent setting.
	*/
	public void toggleShowDialog() {
	showDialog = !showDialog;
	}

	/**
	* Update the persistent store. Call this function after the currently
	* selected value has been found to be ok.
	*/
	public void writePersistedData() {
	// 1. get config pref node
	Preferences node = new ConfigurationScope().getNode(IDEWorkbenchPlugin.IDE_WORKBENCH);

	// 2. get value for showDialog
	node.putBoolean(
	IDE.Preferences.SHOW_WORKSPACE_SELECTION_DIALOG,
	showDialog);

	// 3. use value of numRecent to create proper length array
	node.putInt(IDE.Preferences.MAX_RECENT_WORKSPACES,
	recentWorkspaces.length);

	// move the new selection to the front of the list
	if (selection != null) {
	String oldEntry = recentWorkspaces[0];
	recentWorkspaces[0] = selection;
	for (int i = 1; i < recentWorkspaces.length && oldEntry != null; ++i) {
	if (selection.equals(oldEntry))
	break;
	String tmp = recentWorkspaces[i];
	recentWorkspaces[i] = oldEntry;
	oldEntry = tmp;
	}
	}

	// 4. store values of recent workspaces into array
	String encodedRecentWorkspaces = encodeStoredWorkspacePaths(recentWorkspaces);
	node.put(IDE.Preferences.RECENT_WORKSPACES,
	encodedRecentWorkspaces);

	// 5. store the protocol version used to encode the list
	node.putInt(IDE.Preferences.RECENT_WORKSPACES_PROTOCOL,
	PERS_ENCODING_VERSION_CONFIG_PREFS);

	// 6. store the node
	try {
	node.flush();
	} catch (BackingStoreException e) {
	// do nothing
	}
	}

	/**
	* Look for and read data that might have been persisted from some previous
	* run. Leave the receiver in a default state if no persistent data is
	* found.
	*
	* @return true if a file was successfully read and false otherwise
	*/
	private boolean readPersistedData_file() {
	URL persUrl = null;

	Location configLoc = Platform.getConfigurationLocation();
	if (configLoc != null)
	persUrl = getPersistenceUrl(configLoc.getURL(), false);

	try {
	// inside try to get the safe default creation in the finally
	// clause
	if (persUrl == null)
	return false;

	// E.g.,
	// <launchWorkspaceData>
	// <protocol version="1"/>
	// <alwaysAsk showDialog="1"/>
	// <recentWorkspaces maxLength="5">
	// <workspace path="C:\eclipse\workspace0"/>
	// <workspace path="C:\eclipse\workspace1"/>
	// </recentWorkspaces>
	// </launchWorkspaceData>

	Reader reader = new FileReader(persUrl.getFile());
	XMLMemento memento = XMLMemento.createReadRoot(reader);
	if (memento == null \|\| !compatibleFileProtocol(memento))
	return false;

	IMemento alwaysAskTag = memento.getChild(XML.ALWAYS_ASK);
	showDialog = alwaysAskTag == null ? true : alwaysAskTag.getInteger(
	XML.SHOW_DIALOG).intValue() == 1;

	IMemento recent = memento.getChild(XML.RECENT_WORKSPACES);
	if (recent == null)
	return false;

	Integer maxLength = recent.getInteger(XML.MAX_LENGTH);
	int max = RECENT_MAX_LENGTH;
	if (maxLength != null)
	max = maxLength.intValue();

	IMemento indices[] = recent.getChildren(XML.WORKSPACE);
	if (indices == null \|\| indices.length <= 0)
	return false;

	// if a user has edited maxLength to be shorter than the listed
	// indices, accept the list (its tougher for them to retype a long
	// list of paths than to update a max number)
	max = Math.max(max, indices.length);

	recentWorkspaces = new String[max];
	for (int i = 0; i < indices.length; ++i) {
	String path = indices[i].getString(XML.PATH);
	if (path == null)
	break;
	recentWorkspaces[i] = path;
	}
	} catch (IOException e) {
	// cannot log because instance area has not been set
	return false;
	} catch (WorkbenchException e) {
	// cannot log because instance area has not been set
	return false;
	} finally {
	// create safe default if needed
	if (recentWorkspaces == null)
	recentWorkspaces = new String[RECENT_MAX_LENGTH];
	}

	return true;
	}

	/**
	* Return the current (persisted) value of the "showDialog on startup"
	* preference. Return the global default if the file cannot be accessed.
	*/
	public static boolean getShowDialogValue() {
	// TODO See the long comment in #readPersistedData -- when the
	// transition time is over this method can be changed to
	// read the preference directly.

	ChooseWorkspaceData data = new ChooseWorkspaceData(""); //$NON-NLS-1$

	// return either the value in the file or true, which is the global
	// default
	return data.readPersistedData() ? data.showDialog : true;
	}

	/**
	* Return the current (persisted) value of the "showDialog on startup"
	* preference. Return the global default if the file cannot be accessed.
	*/
	public static void setShowDialogValue(boolean showDialog) {
	// TODO See the long comment in #readPersistedData -- when the
	// transition time is over this method can be changed to
	// read the preference directly.

	ChooseWorkspaceData data = new ChooseWorkspaceData(""); //$NON-NLS-1$

	// update the value and write the new settings
	data.showDialog = showDialog;
	data.writePersistedData();
	}

	/**
	* Look in the config area preference store for the list of recently used
	* workspaces.
	*
	* NOTE: During the transition phase the file will be checked if no config
	* preferences are found.
	*
	* @return true if the values were successfully retrieved and false
	* otherwise
	*/
	public boolean readPersistedData() {
	IPreferenceStore store = new ScopedPreferenceStore(
	new ConfigurationScope(), IDEWorkbenchPlugin.IDE_WORKBENCH);

	// The old way was to store this information in a file, the new is to
	// use the configuration area preference store. To help users with the
	// transition, this code always looks for values in the preference
	// store; they are used if found. If there aren't any related
	// preferences, then the file method is used instead. This class always
	// writes to the preference store, so the fall-back should be needed no
	// more than once per-user, per-configuration.

	// This code always sets the value of the protocol to a non-zero value
	// (currently at 2). If the value comes back as the default (0), then
	// none of the preferences were set, revert to the file method.

	int protocol = store
	.getInt(IDE.Preferences.RECENT_WORKSPACES_PROTOCOL);
	if (protocol == IPreferenceStore.INT_DEFAULT_DEFAULT
	&& readPersistedData_file())
	return true;

	// 2. get value for showDialog
	showDialog = store
	.getBoolean(IDE.Preferences.SHOW_WORKSPACE_SELECTION_DIALOG);

	// 3. use value of numRecent to create proper length array
	int max = store
	.getInt(IDE.Preferences.MAX_RECENT_WORKSPACES);
	max = Math.max(max, RECENT_MAX_LENGTH);

	// 4. load values of recent workspaces into array
	String workspacePathPref = store
	.getString(IDE.Preferences.RECENT_WORKSPACES);
	recentWorkspaces = decodeStoredWorkspacePaths(max, workspacePathPref);

	return true;
	}

	/**
	* The the list of recent workspaces must be stored as a string in the preference node.
	*/
	private static String encodeStoredWorkspacePaths(String[] recent) {
	StringBuffer buff = new StringBuffer();

	String path = null;
	for (int i = 0; i < recent.length; ++i) {
	if (recent[i] == null)
	break;

	if (path != null)
	buff.append(","); //$NON-NLS-1$

	path = recent[i];
	buff.append(path);
	}

	return buff.toString();
	}

	/**
	* The the preference for recent workspaces must be converted from the
	* storage string into an array.
	*/
	private static String[] decodeStoredWorkspacePaths(int max, String prefValue) {
	String[] paths = new String[max];
	if (prefValue == null \|\| prefValue.length() <= 0)
	return paths;

	StringTokenizer tokenizer = new StringTokenizer(prefValue, ","); //$NON-NLS-1$
	for (int i = 0; i < paths.length && tokenizer.hasMoreTokens(); ++i)
	paths[i] = tokenizer.nextToken();

	return paths;
	}

	/**
	* Return true if the protocol used to encode the argument memento is
	* compatible with the receiver's implementation and false otherwise.
	*/
	private static boolean compatibleFileProtocol(IMemento memento) {
	IMemento protocolMemento = memento.getChild(XML.PROTOCOL);
	if (protocolMemento == null)
	return false;

	Integer version = protocolMemento.getInteger(XML.VERSION);
	return version != null && version.intValue() == PERS_ENCODING_VERSION;
	}

	/**
	* The workspace data is stored in the well known file pointed to by the result
	* of this method.
	* @param create If the directory and file does not exist this parameter
	* controls whether it will be created.
	* @return An url to the file and null if it does not exist or could not
	* be created.
	*/
	private static URL getPersistenceUrl(URL baseUrl, boolean create) {
	if (baseUrl == null)
	return null;

	try {
	// make sure the directory exists
	URL url = new URL(baseUrl, PERS_FOLDER);
	File dir = new File(url.getFile());
	if (!dir.exists() && (!create \|\| !dir.mkdir()))
	return null;

	// make sure the file exists
	url = new URL(dir.toURL(), PERS_FILENAME);
	File persFile = new File(url.getFile());
	if (!persFile.exists() && (!create \|\| !persFile.createNewFile()))
	return null;

	return persFile.toURL();
	} catch (IOException e) {
	// cannot log because instance area has not been set
	return null;
	}
	}
	}