PropertyEventDispatcher.java

/*
 * DBeaver - Universal Database Manager
 * Copyright (C) 2010-2017 Serge Rider (serge@jkiss.org)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.jkiss.dbeaver.ui.editors.text;

import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.jkiss.dbeaver.model.preferences.DBPPreferenceListener;
import org.jkiss.dbeaver.model.preferences.DBPPreferenceStore;

import java.util.*;

public final class PropertyEventDispatcher {
	private final Map fHandlerMap= new HashMap();
	private final Map fReverseMap= new HashMap();
	private final DBPPreferenceStore fStore;
	private final DBPPreferenceListener fListener= new DBPPreferenceListener() {
		@Override
        public void preferenceChange(PreferenceChangeEvent event) {
			firePropertyChange(event);
		}
	};
	public PropertyEventDispatcher(DBPPreferenceStore store) {
		Assert.isLegal(store != null);
		fStore= store;
	}
	public void dispose() {
		if (!fReverseMap.isEmpty())
			fStore.removePropertyChangeListener(fListener);
		fReverseMap.clear();
		fHandlerMap.clear();
	}
	private void firePropertyChange(DBPPreferenceListener.PreferenceChangeEvent event) {
		Object value= fHandlerMap.get(event.getProperty());
		if (value instanceof DBPPreferenceListener)
			((DBPPreferenceListener) value).preferenceChange(event);
		else if (value instanceof Set)
			for (Iterator it= ((Set) value).iterator(); it.hasNext(); )
				((DBPPreferenceListener) it.next()).preferenceChange(event);
	}
	public void addPropertyChangeListener(String property, DBPPreferenceListener listener) {
		Assert.isLegal(property != null);
		Assert.isLegal(listener != null);

		if (fReverseMap.isEmpty())
			fStore.addPropertyChangeListener(fListener);

		multiMapPut(fHandlerMap, property, listener);
		multiMapPut(fReverseMap, listener, property);
	}
	private void multiMapPut(Map map, Object key, Object value) {
		Object mapping= map.get(key);
		if (mapping == null) {
			map.put(key, value);
		} else if (mapping instanceof Set) {
			((Set) mapping).add(value);
		} else {
			Set set= new LinkedHashSet();
			set.add(mapping);
			set.add(value);
			map.put(key, set);
		}
	}
	private void multiMapRemove(Map map, Object key, Object value) {
		Object mapping= map.get(key);
		if (mapping instanceof Set) {
			((Set) mapping).remove(value);
		} else if (mapping != null) {
			map.remove(key);
		}
	}
	public void removePropertyChangeListener(IPropertyChangeListener listener) {
		Object value= fReverseMap.get(listener);
		if (value == null)
			return;
		if (value instanceof String) {
			fReverseMap.remove(listener);
			multiMapRemove(fHandlerMap, value, listener);
		} else if (value instanceof Set) {
			fReverseMap.remove(listener);
			for (Iterator it= ((Set) value).iterator(); it.hasNext();)
				multiMapRemove(fHandlerMap, it.next(), listener);
		}

		if (fReverseMap.isEmpty())
			fStore.removePropertyChangeListener(fListener);
	}
}