Java tutorial
/*=============================================================================# # Copyright (c) 2004-2015 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 # Stephan Wahlbrink - support of multiple search contexts and bug fixes #=============================================================================*/ package de.walware.ecommons.preferences.ui; import java.io.IOException; import org.eclipse.core.commands.common.EventManager; import org.eclipse.core.runtime.Assert; import org.eclipse.core.runtime.Platform; import org.eclipse.core.runtime.Plugin; import org.eclipse.core.runtime.SafeRunner; import org.eclipse.core.runtime.preferences.DefaultScope; import org.eclipse.core.runtime.preferences.IEclipsePreferences; import org.eclipse.core.runtime.preferences.IEclipsePreferences.INodeChangeListener; import org.eclipse.core.runtime.preferences.IEclipsePreferences.NodeChangeEvent; import org.eclipse.core.runtime.preferences.IEclipsePreferences.PreferenceChangeEvent; import org.eclipse.core.runtime.preferences.IScopeContext; import org.eclipse.jface.preference.IPersistentPreferenceStore; import org.eclipse.jface.preference.IPreferenceStore; import org.eclipse.jface.resource.JFaceResources; import org.eclipse.jface.util.IPropertyChangeListener; import org.eclipse.jface.util.PropertyChangeEvent; import org.eclipse.jface.util.SafeRunnable; import org.eclipse.ui.internal.WorkbenchMessages; import org.osgi.service.prefs.BackingStoreException; /** * The ScopedPreferenceStore is an IPreferenceStore that uses the scopes * provided in org.eclipse.core.runtime.preferences. * <p> * A ScopedPreferenceStore does the lookup of a preference based on it's search * scopes and sets the value of the preference based on its store scope. * </p> * <p> * The default scope is always included in the search scopes when searching for * preference values. * </p> * * @see org.eclipse.core.runtime.preferences * @since 3.1 */ public class ScopedPreferenceStore extends EventManager implements IPreferenceStore, IPersistentPreferenceStore { // See Eclipse bug #123903, but low priority /** * The storeContext is the context where values will stored with the * setValue methods. If there are no searchContexts this will be the search * context. (along with the "default" context) */ private final IScopeContext storeContext; /** * The searchContext is the array of contexts that will be used by the get * methods for searching for values. */ private IScopeContext[] searchContexts; /** * A boolean to indicate the property changes should not be propagated. */ protected boolean silentRunning = false; /** * The listener on the IEclipsePreferences. This is used to forward updates * to the property change listeners on the preference store. */ IEclipsePreferences.IPreferenceChangeListener preferencesListener; private IEclipsePreferences.IPreferenceChangeListener[] searchPreferencesListeners; /** * The default context is the context where getDefault and setDefault * methods will search. This context is also used in the search. */ private final IScopeContext defaultContext = new DefaultScope(); /** * The nodeQualifer is the string used to look up the node in the contexts. */ private final String nodeQualifier; /** * The defaultQualifier is the string used to look up the default node. */ private final String defaultQualifier; /** * Boolean value indicating whether or not this store has changes to be * saved. */ private boolean dirty; /** * Create a new instance of the receiver. Store the values in context in the * node looked up by qualifier. <strong>NOTE:</strong> Any instance of * ScopedPreferenceStore should call * * @param context * the scope to store to * @param qualifier * the qualifier used to look up the preference node * @param defaultQualifierPath * the qualifier used when looking up the defaults */ public ScopedPreferenceStore(final IScopeContext context, final String qualifier, final String defaultQualifierPath) { this.storeContext = context; this.nodeQualifier = qualifier; this.defaultQualifier = defaultQualifierPath; ((IEclipsePreferences) getStorePreferences().parent()).addNodeChangeListener(getNodeChangeListener()); } /** * Create a new instance of the receiver. Store the values in context in the * node looked up by qualifier. * * @param context * the scope to store to * @param qualifier * the qualifer used to look up the preference node */ public ScopedPreferenceStore(final IScopeContext context, final String qualifier) { this(context, qualifier, qualifier); } /** * Return a node change listener that adds a removes the receiver when nodes * change. * * @return INodeChangeListener */ private INodeChangeListener getNodeChangeListener() { return new IEclipsePreferences.INodeChangeListener() { @Override public void added(final NodeChangeEvent event) { if (nodeQualifier.equals(event.getChild().name()) && isListenerAttached()) { getStorePreferences().addPreferenceChangeListener(preferencesListener); } } @Override public void removed(final NodeChangeEvent event) { // Do nothing as there are no events from removed node } }; } /** * Initialize the preferences listener. */ private void initializePreferencesListener() { if (searchContexts == null && preferencesListener == null) { preferencesListener = new IEclipsePreferences.IPreferenceChangeListener() { @Override public void preferenceChange(final PreferenceChangeEvent event) { if (silentRunning) { return; } Object oldValue = event.getOldValue(); Object newValue = event.getNewValue(); final String key = event.getKey(); if (newValue == null) { newValue = getDefault(key, oldValue); } else if (oldValue == null) { oldValue = getDefault(key, newValue); } firePropertyChangeEvent(event.getKey(), oldValue, newValue); } }; getStorePreferences().addPreferenceChangeListener(preferencesListener); } else if (searchContexts != null && searchPreferencesListeners == null) { searchPreferencesListeners = new IEclipsePreferences.IPreferenceChangeListener[searchContexts.length]; for (int i = 0; i < searchContexts.length; i++) { final int idxSearchContext = i; searchPreferencesListeners[idxSearchContext] = new IEclipsePreferences.IPreferenceChangeListener() { @Override public void preferenceChange(final PreferenceChangeEvent event) { if (silentRunning) { return; } final IEclipsePreferences[] preferences = getPreferenceNodes(true); final String key = event.getKey(); Object oldValue = event.getOldValue(); Object newValue = null; int idxNewContext = preferences.length; for (int j = 0; j < preferences.length; j++) { final String value = preferences[j].get(key, null); if (value != null) { if (newValue == null) { newValue = value; idxNewContext = j; } else if (oldValue == null) { // new value was added oldValue = value; } } if (newValue != null && oldValue != null) { break; } } if (idxNewContext < idxSearchContext) { return; } if (newValue == null) { newValue = getDefault(key, oldValue); } if (oldValue == null) { oldValue = getDefault(key, newValue); } if (oldValue != null && oldValue.equals(newValue)) { return; } firePropertyChangeEvent(event.getKey(), oldValue, newValue); } }; searchContexts[i].getNode(nodeQualifier).addPreferenceChangeListener(searchPreferencesListeners[i]); } } } /** * Does its best at determining the default value for the given key. Checks * the given object's type and then looks in the list of defaults to see if * a value exists. If not or if there is a problem converting the value, the * default default value for that type is returned. * * @param key * the key to search * @param obj * the object who default we are looking for * @return Object or <code>null</code> */ Object getDefault(final String key, final Object obj) { final IEclipsePreferences defaults = getDefaultPreferences(); if (obj instanceof String) { return defaults.get(key, STRING_DEFAULT_DEFAULT); } else if (obj instanceof Integer) { return Integer.valueOf(defaults.getInt(key, INT_DEFAULT_DEFAULT)); } else if (obj instanceof Double) { return Double.valueOf(defaults.getDouble(key, DOUBLE_DEFAULT_DEFAULT)); } else if (obj instanceof Float) { return Float.valueOf(defaults.getFloat(key, FLOAT_DEFAULT_DEFAULT)); } else if (obj instanceof Long) { return Long.valueOf(defaults.getLong(key, LONG_DEFAULT_DEFAULT)); } else if (obj instanceof Boolean) { return Boolean.valueOf(defaults.getBoolean(key, BOOLEAN_DEFAULT_DEFAULT)); } else { return null; } } /** * Return the IEclipsePreferences node associated with this store. * * @return the preference node for this store */ IEclipsePreferences getStorePreferences() { return storeContext.getNode(nodeQualifier); } /** * Return the default IEclipsePreferences for this store. * * @return this store's default preference node */ private IEclipsePreferences getDefaultPreferences() { return defaultContext.getNode(defaultQualifier); } @Override public void addPropertyChangeListener(final IPropertyChangeListener listener) { initializePreferencesListener();// Create the preferences listener if it // does not exist addListenerObject(listener); } /** * Return the preference path to search preferences on. This is the list of * preference nodes based on the scope contexts for this store. If there are * no search contexts set, then return this store's context. * <p> * Whether or not the default context should be included in the resulting * list is specified by the <code>includeDefault</code> parameter. * </p> * * @param includeDefault * <code>true</code> if the default context should be included * and <code>false</code> otherwise * @return IEclipsePreferences[] */ private IEclipsePreferences[] getPreferenceNodes(final boolean includeDefault) { // if the user didn't specify a search order, then return the scope that // this store was created on. (and optionally the default) if (searchContexts == null) { if (includeDefault) { return new IEclipsePreferences[] { getStorePreferences(), getDefaultPreferences() }; } return new IEclipsePreferences[] { getStorePreferences() }; } // otherwise the user specified a search order so return the appropriate // nodes based on it int length = searchContexts.length; if (includeDefault) { length++; } final IEclipsePreferences[] preferences = new IEclipsePreferences[length]; for (int i = 0; i < searchContexts.length; i++) { preferences[i] = searchContexts[i].getNode(nodeQualifier); } if (includeDefault) { preferences[length - 1] = getDefaultPreferences(); } return preferences; } /** * Set the search contexts to scopes. When searching for a value the seach * will be done in the order of scope contexts and will not search the * storeContext unless it is in this list. * <p> * If the given list is <code>null</code>, then clear this store's search * contexts. This means that only this store's scope context and default * scope will be used during preference value searching. * </p> * <p> * The defaultContext will be added to the end of this list automatically * and <em>MUST NOT</em> be included by the user. * </p> * * @param scopes * a list of scope contexts to use when searching, or * <code>null</code> */ public void setSearchContexts(final IScopeContext[] scopes) { // Assert that the default was not included (we automatically add it to // the end) if (scopes != null) { for (int i = 0; i < scopes.length; i++) { if (scopes[i].equals(defaultContext)) { Assert.isTrue(false, WorkbenchMessages.ScopedPreferenceStore_DefaultAddedError); } } } if (isListenerAttached()) { disposePreferenceStoreListener(); } this.searchContexts = scopes; if (isListenerAttached()) { initializePreferencesListener(); } } @Override public boolean contains(final String name) { if (name == null) { return false; } return (Platform.getPreferencesService().get(name, null, getPreferenceNodes(true))) != null; } @Override public void firePropertyChangeEvent(final String name, final Object oldValue, final Object newValue) { // important: create intermediate array to protect against listeners // being added/removed during the notification final Object[] list = getListeners(); if (list.length == 0) { return; } final PropertyChangeEvent event = new PropertyChangeEvent(this, name, oldValue, newValue); for (int i = 0; i < list.length; i++) { final IPropertyChangeListener listener = (IPropertyChangeListener) list[i]; SafeRunner.run(new SafeRunnable(JFaceResources.getString("PreferenceStore.changeError")) { //$NON-NLS-1$ @Override public void run() { listener.propertyChange(event); } }); } } @Override public boolean getBoolean(final String name) { final String value = internalGet(name); return value == null ? BOOLEAN_DEFAULT_DEFAULT : Boolean.valueOf(value).booleanValue(); } @Override public boolean getDefaultBoolean(final String name) { return getDefaultPreferences().getBoolean(name, BOOLEAN_DEFAULT_DEFAULT); } @Override public double getDefaultDouble(final String name) { return getDefaultPreferences().getDouble(name, DOUBLE_DEFAULT_DEFAULT); } @Override public float getDefaultFloat(final String name) { return getDefaultPreferences().getFloat(name, FLOAT_DEFAULT_DEFAULT); } @Override public int getDefaultInt(final String name) { return getDefaultPreferences().getInt(name, INT_DEFAULT_DEFAULT); } @Override public long getDefaultLong(final String name) { return getDefaultPreferences().getLong(name, LONG_DEFAULT_DEFAULT); } @Override public String getDefaultString(final String name) { return getDefaultPreferences().get(name, STRING_DEFAULT_DEFAULT); } @Override public double getDouble(final String name) { final String value = internalGet(name); if (value == null) { return DOUBLE_DEFAULT_DEFAULT; } try { return Double.parseDouble(value); } catch (final NumberFormatException e) { return DOUBLE_DEFAULT_DEFAULT; } } /** * Return the string value for the specified key. Look in the nodes which * are specified by this object's list of search scopes. If the value does * not exist then return <code>null</code>. * * @param key * the key to search with * @return String or <code>null</code> if the value does not exist. */ private String internalGet(final String key) { return Platform.getPreferencesService().get(key, null, getPreferenceNodes(true)); } @Override public float getFloat(final String name) { final String value = internalGet(name); if (value == null) { return FLOAT_DEFAULT_DEFAULT; } try { return Float.parseFloat(value); } catch (final NumberFormatException e) { return FLOAT_DEFAULT_DEFAULT; } } @Override public int getInt(final String name) { final String value = internalGet(name); if (value == null) { return INT_DEFAULT_DEFAULT; } try { return Integer.parseInt(value); } catch (final NumberFormatException e) { return INT_DEFAULT_DEFAULT; } } @Override public long getLong(final String name) { final String value = internalGet(name); if (value == null) { return LONG_DEFAULT_DEFAULT; } try { return Long.parseLong(value); } catch (final NumberFormatException e) { return LONG_DEFAULT_DEFAULT; } } @Override public String getString(final String name) { final String value = internalGet(name); return value == null ? STRING_DEFAULT_DEFAULT : value; } @Override public boolean isDefault(final String name) { if (name == null) { return false; } return (Platform.getPreferencesService().get(name, null, getPreferenceNodes(false))) == null; } @Override public boolean needsSaving() { return dirty; } @Override public void putValue(final String name, final String value) { try { // Do not notify listeners silentRunning = true; getStorePreferences().put(name, value); } finally { // Be sure that an exception does not stop property updates silentRunning = false; dirty = true; } } @Override public void removePropertyChangeListener(final IPropertyChangeListener listener) { removeListenerObject(listener); if (!isListenerAttached()) { disposePreferenceStoreListener(); } } @Override public void setDefault(final String name, final double value) { getDefaultPreferences().putDouble(name, value); } /* * (non-Javadoc) * * @see org.eclipse.jface.preference.IPreferenceStore#setDefault(java.lang.String, * float) */ @Override public void setDefault(final String name, final float value) { getDefaultPreferences().putFloat(name, value); } @Override public void setDefault(final String name, final int value) { getDefaultPreferences().putInt(name, value); } @Override public void setDefault(final String name, final long value) { getDefaultPreferences().putLong(name, value); } @Override public void setDefault(final String name, final String defaultObject) { getDefaultPreferences().put(name, defaultObject); } @Override public void setDefault(final String name, final boolean value) { getDefaultPreferences().putBoolean(name, value); } @Override public void setToDefault(final String name) { final String oldValue = getString(name); final String defaultValue = getDefaultString(name); try { silentRunning = true;// Turn off updates from the store // removing a non-existing preference is a no-op so call the Core // API directly getStorePreferences().remove(name); dirty = true; if (oldValue != defaultValue) { firePropertyChangeEvent(name, oldValue, defaultValue); } } finally { silentRunning = false;// Restart listening to preferences } } @Override public void setValue(final String name, final double value) { final double oldValue = getDouble(name); if (oldValue == value) { return; } try { silentRunning = true;// Turn off updates from the store if (getDefaultDouble(name) == value) { getStorePreferences().remove(name); } else { getStorePreferences().putDouble(name, value); } dirty = true; firePropertyChangeEvent(name, Double.valueOf(oldValue), Double.valueOf(value)); } finally { silentRunning = false;// Restart listening to preferences } } @Override public void setValue(final String name, final float value) { final float oldValue = getFloat(name); if (oldValue == value) { return; } try { silentRunning = true;// Turn off updates from the store if (getDefaultFloat(name) == value) { getStorePreferences().remove(name); } else { getStorePreferences().putFloat(name, value); } dirty = true; firePropertyChangeEvent(name, Float.valueOf(oldValue), Float.valueOf(value)); } finally { silentRunning = false;// Restart listening to preferences } } @Override public void setValue(final String name, final int value) { final int oldValue = getInt(name); if (oldValue == value) { return; } try { silentRunning = true;// Turn off updates from the store if (getDefaultInt(name) == value) { getStorePreferences().remove(name); } else { getStorePreferences().putInt(name, value); } dirty = true; firePropertyChangeEvent(name, Integer.valueOf(oldValue), Integer.valueOf(value)); } finally { silentRunning = false;// Restart listening to preferences } } @Override public void setValue(final String name, final long value) { final long oldValue = getLong(name); if (oldValue == value) { return; } try { silentRunning = true;// Turn off updates from the store if (getDefaultLong(name) == value) { getStorePreferences().remove(name); } else { getStorePreferences().putLong(name, value); } dirty = true; firePropertyChangeEvent(name, Long.valueOf(oldValue), Long.valueOf(value)); } finally { silentRunning = false;// Restart listening to preferences } } @Override public void setValue(final String name, final String value) { // Do not turn on silent running here as Strings are propagated if (value == null || getDefaultString(name).equals(value)) { getStorePreferences().remove(name); } else { getStorePreferences().put(name, value); } dirty = true; } @Override public void setValue(final String name, final boolean value) { final boolean oldValue = getBoolean(name); if (oldValue == value) { return; } try { silentRunning = true;// Turn off updates from the store if (getDefaultBoolean(name) == value) { getStorePreferences().remove(name); } else { getStorePreferences().putBoolean(name, value); } dirty = true; firePropertyChangeEvent(name, Boolean.valueOf(oldValue), Boolean.valueOf(value)); } finally { silentRunning = false;// Restart listening to preferences } } @Override public void save() throws IOException { try { getStorePreferences().flush(); dirty = false; } catch (final BackingStoreException e) { throw new IOException(e.getMessage()); } } /** * Dispose the receiver. */ private void disposePreferenceStoreListener() { final IEclipsePreferences root = (IEclipsePreferences) Platform.getPreferencesService().getRootNode() .node(Plugin.PLUGIN_PREFERENCE_SCOPE); try { if (!(root.nodeExists(nodeQualifier))) { return; } } catch (final BackingStoreException e) { return;// No need to report here as the node won't have the // listener } IEclipsePreferences preferences = getStorePreferences(); if (preferences != null && preferencesListener != null) { preferences.removePreferenceChangeListener(preferencesListener); preferencesListener = null; } if (searchContexts != null && searchPreferencesListeners != null) { for (int i = 0; i < searchContexts.length; i++) { preferences = searchContexts[i].getNode(nodeQualifier); if (preferences != null) { preferences.removePreferenceChangeListener(searchPreferencesListeners[i]); } } } } }