KeyStoreModelEventManager.java

/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * 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 com.motorolamobility.studio.android.certmanager.event;

import java.util.ArrayList;
import java.util.List;

import com.motorolamobility.studio.android.certmanager.ui.model.ITreeNode;

/**
 * Manager which notifies {@link IKeyStoreModelListener} registered that a {@link KeyStoreModelEvent} occurred. 
 * It is a singleton that needs to be called by the hierarchy of {@link ITreeNode} items when they modify the {@link ITreeNode}.
 */
public class KeyStoreModelEventManager
{
    private static KeyStoreModelEventManager _instance;

    private final List<IKeyStoreModelListener> listeners = new ArrayList<IKeyStoreModelListener>();

    private KeyStoreModelEventManager()
    {
        // Singleton - private default constructor prevents instantiations by other classes.  
    }

    /**
     * Return the singleton instance of KeyStoreModelEventManager.
     * */
    public synchronized static KeyStoreModelEventManager getInstance()
    {
        if (_instance == null)
        {
            _instance = new KeyStoreModelEventManager();
        }
        return _instance;
    }

    /**
     * Add the parameter {@code listener} to the list of KeyStore event listeners.
     * @param listener The listener to be added.
     * */
    public void addListener(IKeyStoreModelListener listener)
    {
        synchronized (listener)
        {
            listeners.add(listener);
        }
    }

    /**
     * Remove the parameter {@code listener} to the list of KeyStore event listeners.
     * @param listener The listener to be removed.
     * */
    public void removeListener(IKeyStoreModelListener listener)
    {
        synchronized (listener)
        {
            listeners.remove(listener);
        }
    }

    /**
     * Fire/notify/deliver the event to registered listeners.  
     * @param node {@link ITreeNode} that needs to refresh the view based on the model
     * @param eventType Event that occurred. 
     */
    public void fireEvent(ITreeNode treeNodeItem, KeyStoreModelEvent.EventType eventType)
    {
        KeyStoreModelEvent keyStoreModelEvent = new KeyStoreModelEvent(treeNodeItem, eventType);
        synchronized (listeners)
        {
            if (listeners != null)
            {
                for (IKeyStoreModelListener listener : listeners)
                {
                    switch (eventType)
                    {
                        case ADD:
                            listener.handleNodeAdditionEvent(keyStoreModelEvent);
                            break;
                        case REMOVE:
                            listener.handleNodeRemovalEvent(keyStoreModelEvent);
                            break;
                        case UPDATE:
                            listener.handleNodeUpdateEvent(keyStoreModelEvent);
                            break;
                        case COLLAPSE:
                            listener.handleNodeCollapseEvent(keyStoreModelEvent);
                            break;
                        case REFRESH:
                            listener.handleNodeRefreshEvent(keyStoreModelEvent);
                            break;
                        case CLEAR:
                            listener.handleNodeClearEvent(keyStoreModelEvent);
                            break;
                        default:
                            break;
                    }
                }
            }
        }
    }
}