001/*
002 * Sonar, open source software quality management tool.
003 * Copyright (C) 2008-2012 SonarSource
004 * mailto:contact AT sonarsource DOT com
005 *
006 * Sonar is free software; you can redistribute it and/or
007 * modify it under the terms of the GNU Lesser General Public
008 * License as published by the Free Software Foundation; either
009 * version 3 of the License, or (at your option) any later version.
010 *
011 * Sonar is distributed in the hope that it will be useful,
012 * but WITHOUT ANY WARRANTY; without even the implied warranty of
013 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014 * Lesser General Public License for more details.
015 *
016 * You should have received a copy of the GNU Lesser General Public
017 * License along with Sonar; if not, write to the Free Software
018 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
019 */
020package org.sonar.batch.events;
021
022import com.google.common.collect.Lists;
023import org.sonar.api.batch.events.EventHandler;
024
025import java.util.List;
026
027/**
028 * Dispatches {@link BatchEvent}s. Eases decoupling by allowing objects to interact without having direct dependencies upon one another, and
029 * without requiring event sources to deal with maintaining handler lists.
030 */
031public class EventBus {
032
033  private EventHandler[] registeredHandlers;
034
035  public EventBus(EventHandler[] handlers) {
036    this.registeredHandlers = handlers;
037  }
038
039  /**
040   * Fires the given event.
041   */
042  public void fireEvent(BatchEvent event) {
043    doFireEvent(event);
044  }
045
046  private void doFireEvent(BatchEvent event) {
047    List<EventHandler> handlers = getDispatchList(event.getType());
048    for (EventHandler handler : handlers) {
049      event.dispatch(handler);
050    }
051  }
052
053  private List<EventHandler> getDispatchList(Class<? extends EventHandler> handlerType) {
054    List<EventHandler> result = Lists.newArrayList();
055    for (EventHandler handler : registeredHandlers) {
056      if (handlerType.isAssignableFrom(handler.getClass())) {
057        result.add(handler);
058      }
059    }
060    return result;
061  }
062
063}