pluginpreferencestore.java

配置文件

/**
 * Copyright (c) 2003-2005 Craig Setera
 * All Rights Reserved.
 * Licensed under the Eclipse Public License - v 1.0
 * For more information see http://www.eclipse.org/legal/epl-v10.html
 */
package eclipseme.ui.internal.utils;

import java.io.IOException;

import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.Plugin;
import org.eclipse.core.runtime.Preferences;
import org.eclipse.jface.preference.IPersistentPreferenceStore;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.ListenerList;
import org.eclipse.jface.util.SafeRunnable;

public class PluginPreferenceStore 
	implements IPersistentPreferenceStore 
{

	/**
	 * Flag to indicate that the listener has been added.
	 */
	private boolean listenerAdded = false;

	/** The owner of the preferences being wrapped */
	private Plugin owner;
	
	/**
	 * The underlying core runtime preference store; <code>null</code> if it
	 * has not been initialized yet.
	 */
	private Preferences prefs = null;

	/**
	 * Identity list of old listeners (element type: 
	 * <code>org.eclipse.jface.util.IPropertyChangeListener</code>).
	 */
	private ListenerList listeners = new ListenerList();

	/**
	 * Indicates whether property change events should be suppressed
	 * (used in implementation of <code>putValue</code>). Initially
	 * and usually <code>false</code>.
	 * 
	 * @see IPreferenceStore#putValue
	 */
	private boolean silentRunning = false;
	
	/**
	 * Creates a new instance for the this plug-in.
	 */
	public PluginPreferenceStore(Plugin owner, Preferences pluginPreferences) {
		this.owner = owner;
		prefs = pluginPreferences;
	}

	/**
	 * Initializes this preference store.
	 */
	void initialize() {
		// ensure initialization is only done once.
		if (this.prefs != null) {
			return;
		}

		// avoid adding the listener a second time when reentered
		if (!this.listenerAdded) {
			// register listener that funnels everything to firePropertyChangeEvent
			this
				.prefs
				.addPropertyChangeListener(
					new Preferences
					.IPropertyChangeListener() {
				public void propertyChange(
					Preferences.PropertyChangeEvent event) {
					if (!silentRunning) {
						firePropertyChangeEvent(
							event.getProperty(),
							event.getOldValue(),
							event.getNewValue());
					}
				}
			});
			this.listenerAdded = true;
		}
	}

	/**
	 * Returns the underlying preference store.
	 * 
	 * @return the underlying preference store
	 */
	private Preferences getPrefs() {
		if (prefs == null) {
			// although we try to ensure initialization is done eagerly,
			// this cannot be guaranteed, so ensure it is done here
			initialize();
		}
		return prefs;
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public void addPropertyChangeListener(final IPropertyChangeListener listener) {
		listeners.add(listener);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public void removePropertyChangeListener(IPropertyChangeListener listener) {
		listeners.remove(listener);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public void firePropertyChangeEvent(
		String name,
		Object oldValue,
		Object newValue) {

		// efficiently handle case of 0 listeners
		if (listeners.isEmpty()) {
			// no one interested
			return;
		}

		// important: create intermediate array to protect against listeners 
		// being added/removed during the notification
		final Object[] list = listeners.getListeners();
		final org.eclipse.jface.util.PropertyChangeEvent event =
			new org.eclipse.jface.util.PropertyChangeEvent(this, name, oldValue, newValue);
		for (int i = 0; i < list.length; i++) {
			final IPropertyChangeListener listener = (IPropertyChangeListener) list[i];
			Platform.run(new SafeRunnable("Preference Change Error") {
				public void run() {
					listener.propertyChange(event);
				}
			});
		}

	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public boolean contains(String name) {
		return getPrefs().contains(name);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public boolean getBoolean(String name) {
		return getPrefs().getBoolean(name);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public boolean getDefaultBoolean(String name) {
		return getPrefs().getDefaultBoolean(name);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public double getDefaultDouble(String name) {
		return getPrefs().getDefaultDouble(name);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public float getDefaultFloat(String name) {
		return getPrefs().getDefaultFloat(name);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public int getDefaultInt(String name) {
		return getPrefs().getDefaultInt(name);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public long getDefaultLong(String name) {
		return getPrefs().getDefaultLong(name);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public String getDefaultString(String name) {
		return getPrefs().getDefaultString(name);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public double getDouble(String name) {
		return getPrefs().getDouble(name);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public float getFloat(String name) {
		return getPrefs().getFloat(name);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public int getInt(String name) {
		return getPrefs().getInt(name);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public long getLong(String name) {
		return getPrefs().getLong(name);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public String getString(String name) {
		return getPrefs().getString(name);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public boolean isDefault(String name) {
		return getPrefs().isDefault(name);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public boolean needsSaving() {
		return getPrefs().needsSaving();
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public void putValue(String name, String value) {
		try {
			// temporarily suppress event notification while setting value
			silentRunning = true;
			getPrefs().setValue(name, value);
		} finally {
			silentRunning = false;
		}
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public void setDefault(String name, double value) {
		getPrefs().setDefault(name, value);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public void setDefault(String name, float value) {
		getPrefs().setDefault(name, value);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public void setDefault(String name, int value) {
		getPrefs().setDefault(name, value);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public void setDefault(String name, long value) {
		getPrefs().setDefault(name, value);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public void setDefault(String name, String value) {
		getPrefs().setDefault(name, value);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public void setDefault(String name, boolean value) {
		getPrefs().setDefault(name, value);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public void setToDefault(String name) {
		getPrefs().setToDefault(name);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public void setValue(String name, double value) {
		getPrefs().setValue(name, value);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public void setValue(String name, float value) {
		getPrefs().setValue(name, value);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public void setValue(String name, int value) {
		getPrefs().setValue(name, value);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public void setValue(String name, long value) {
		getPrefs().setValue(name, value);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public void setValue(String name, String value) {
		getPrefs().setValue(name, value);
	}

	/* (non-javadoc)
	 * Method declared on IPreferenceStore
	 */
	public void setValue(String name, boolean value) {
		getPrefs().setValue(name, value);
	}
	
	/**
	 * @see org.eclipse.jface.preference.IPersistentPreferenceStore#save()
	 */
	public void save() throws IOException {
		owner.savePluginPreferences();
	}
}