org.ow2.bonita.pvm.internal.util.DefaultObservable Maven / Gradle / Ivy

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package org.ow2.bonita.pvm.internal.util;

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

import org.ow2.bonita.pvm.PvmException;

/**
 * default implementation of the {@link Observable} interface.
 * 
 * @author Tom Baeyens
 */
public class DefaultObservable implements Observable {

  protected List listeners = null;

  public void addListener(Listener listener) {
    if (listener == null) {
      throw new PvmException("listener is null");
    }
    if (listeners == null) {
      listeners = new ArrayList();
    }
    listeners.add(listener);
  }

  public void removeListener(Listener listener) {
    if (listener == null) {
      throw new PvmException("listener is null");
    }
    if (listeners != null) {
      listeners.remove(listener);
    }
  }

  public Listener addListener(Listener listener, String eventName) {
    if (eventName == null) {
      throw new PvmException("eventName is null");
    }

    List eventNames = new ArrayList();
    eventNames.add(eventName);

    return addListener(listener, eventNames);
  }

  public Listener addListener(Listener listener, List eventNames) {
    if (listener == null) {
      throw new PvmException("listener is null");
    }
    if (eventNames == null) {
      throw new PvmException("eventNames is null");
    }
    FilterListener filterListener = new FilterListener(listener, eventNames);
    addListener(filterListener);
    return filterListener;
  }

  public void fire(String eventName) {
    fire(eventName, null);
  }

  public void fire(String eventName, Object info) {
    if (listeners != null) {
      for (Listener listener : listeners) {
        listener.event(this, eventName, info);
      }
    }
  }

  public List getListeners() {
    return listeners;
  }
}