All Downloads are FREE. Search and download functionalities are using the official Maven repository.

org.eclipse.jetty.util.component.Container Maven / Gradle / Ivy

There is a newer version: 8.2.0.v20160908
Show newest version
//
//  ========================================================================
//  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
//  ------------------------------------------------------------------------
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  and Apache License v2.0 which accompanies this distribution.
//
//      The Eclipse Public License is available at
//      http://www.eclipse.org/legal/epl-v10.html
//
//      The Apache License v2.0 is available at
//      http://www.opensource.org/licenses/apache2.0.php
//
//  You may elect to redistribute this code under either of these licenses.
//  ========================================================================
//

package org.eclipse.jetty.util.component;
import java.lang.ref.WeakReference;
import java.util.EventListener;
import java.util.concurrent.CopyOnWriteArrayList;

import org.eclipse.jetty.util.LazyList;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;

/* ------------------------------------------------------------ */
/** Container.
 * This class allows a containment events to be generated from update methods.
 * 
 * The style of usage is: 
 *   public void setFoo(Foo foo)
 *   {
 *       getContainer().update(this,this.foo,foo,"foo");
 *       this.foo=foo;
 *   }
 *   
 *   public void setBars(Bar[] bars)
 *   {
 *       getContainer().update(this,this.bars,bars,"bar");
 *       this.bars=bars;
 *   }
 * 
*/ public class Container { private static final Logger LOG = Log.getLogger(Container.class); private final CopyOnWriteArrayList _listeners=new CopyOnWriteArrayList(); public void addEventListener(Container.Listener listener) { _listeners.add(listener); } public void removeEventListener(Container.Listener listener) { _listeners.remove(listener); } /* ------------------------------------------------------------ */ /** Update single parent to child relationship. * @param parent The parent of the child. * @param oldChild The previous value of the child. If this is non null and differs from child, then a remove event is generated. * @param child The current child. If this is non null and differs from oldChild, then an add event is generated. * @param relationship The name of the relationship */ public void update(Object parent, Object oldChild, final Object child, String relationship) { if (oldChild!=null && !oldChild.equals(child)) remove(parent,oldChild,relationship); if (child!=null && !child.equals(oldChild)) add(parent,child,relationship); } /* ------------------------------------------------------------ */ /** Update single parent to child relationship. * @param parent The parent of the child. * @param oldChild The previous value of the child. If this is non null and differs from child, then a remove event is generated. * @param child The current child. If this is non null and differs from oldChild, then an add event is generated. * @param relationship The name of the relationship * @param addRemove If true add/remove is called for the new/old children as well as the relationships */ public void update(Object parent, Object oldChild, final Object child, String relationship,boolean addRemove) { if (oldChild!=null && !oldChild.equals(child)) { remove(parent,oldChild,relationship); if (addRemove) removeBean(oldChild); } if (child!=null && !child.equals(oldChild)) { if (addRemove) addBean(child); add(parent,child,relationship); } } /* ------------------------------------------------------------ */ /** Update multiple parent to child relationship. * @param parent The parent of the child. * @param oldChildren The previous array of children. A remove event is generated for any child in this array but not in the children array. * This array is modified and children that remain in the new children array are nulled out of the old children array. * @param children The current array of children. An add event is generated for any child in this array but not in the oldChildren array. * @param relationship The name of the relationship */ public void update(Object parent, Object[] oldChildren, final Object[] children, String relationship) { update(parent,oldChildren,children,relationship,false); } /* ------------------------------------------------------------ */ /** Update multiple parent to child relationship. * @param parent The parent of the child. * @param oldChildren The previous array of children. A remove event is generated for any child in this array but not in the children array. * This array is modified and children that remain in the new children array are nulled out of the old children array. * @param children The current array of children. An add event is generated for any child in this array but not in the oldChildren array. * @param relationship The name of the relationship * @param addRemove If true add/remove is called for the new/old children as well as the relationships */ public void update(Object parent, Object[] oldChildren, final Object[] children, String relationship, boolean addRemove) { Object[] newChildren = null; if (children!=null) { newChildren = new Object[children.length]; for (int i=children.length;i-->0;) { boolean new_child=true; if (oldChildren!=null) { for (int j=oldChildren.length;j-->0;) { if (children[i]!=null && children[i].equals(oldChildren[j])) { oldChildren[j]=null; new_child=false; } } } if (new_child) newChildren[i]=children[i]; } } if (oldChildren!=null) { for (int i=oldChildren.length;i-->0;) { if (oldChildren[i]!=null) { remove(parent,oldChildren[i],relationship); if (addRemove) removeBean(oldChildren[i]); } } } if (newChildren!=null) { for (int i=0;i _parent; private final WeakReference _child; private String _relationship; private Container _container; private Relationship(Container container, Object parent,Object child, String relationship) { _container=container; _parent=new WeakReference(parent); _child=new WeakReference(child); _relationship=relationship; } public Container getContainer() { return _container; } public Object getChild() { return _child.get(); } public Object getParent() { return _parent.get(); } public String getRelationship() { return _relationship; } @Override public String toString() { return _parent+"---"+_relationship+"-->"+_child; } @Override public int hashCode() { return _parent.hashCode()+_child.hashCode()+_relationship.hashCode(); } @Override public boolean equals(Object o) { if (o==null || !(o instanceof Relationship)) return false; Relationship r = (Relationship)o; return r._parent.get()==_parent.get() && r._child.get()==_child.get() && r._relationship.equals(_relationship); } } /* ------------------------------------------------------------ */ /** Listener. * A listener for Container events. */ public interface Listener extends EventListener { public void addBean(Object bean); public void removeBean(Object bean); public void add(Container.Relationship relationship); public void remove(Container.Relationship relationship); } }