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view src/org/eclipse/jetty/util/component/Container.java @ 830:7c737c376bc3
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author | Franklin Schmidt <fschmidt@gmail.com> |
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date | Thu, 15 Sep 2016 18:30:38 -0600 |
parents | 8e9db0bbf4f9 |
children |
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// // ======================================================================== // 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.slf4j.Logger; import org.slf4j.LoggerFactory; /* ------------------------------------------------------------ */ /** Container. * This class allows a containment events to be generated from update methods. * * The style of usage is: <pre> * 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; * } * </pre> */ public class Container { private static final Logger LOG = LoggerFactory.getLogger(Container.class); private final CopyOnWriteArrayList<Container.Listener> _listeners=new CopyOnWriteArrayList<Container.Listener>(); 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 <code>child</code>, then a remove event is generated. * @param child The current child. If this is non null and differs from <code>oldChild</code>, 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 <code>child</code>, then a remove event is generated. * @param child The current child. If this is non null and differs from <code>oldChild</code>, 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 <code>children</code> 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 <code>oldChildren</code> 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 <code>children</code> 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 <code>oldChildren</code> 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<newChildren.length;i++) if (newChildren[i]!=null) { if (addRemove) addBean(newChildren[i]); add(parent,newChildren[i],relationship); } } } /* ------------------------------------------------------------ */ public void addBean(Object obj) { if (_listeners!=null) { for (int i=0; i<LazyList.size(_listeners); i++) { Listener listener=(Listener)LazyList.get(_listeners, i); listener.addBean(obj); } } } /* ------------------------------------------------------------ */ public void removeBean(Object obj) { if (_listeners!=null) { for (int i=0; i<LazyList.size(_listeners); i++) ((Listener)LazyList.get(_listeners, i)).removeBean(obj); } } /* ------------------------------------------------------------ */ /** Add a parent child relationship * @param parent * @param child * @param relationship */ private void add(Object parent, Object child, String relationship) { if (LOG.isDebugEnabled()) LOG.debug("Container "+parent+" + "+child+" as "+relationship); if (_listeners!=null) { Relationship event=new Relationship(this,parent,child,relationship); for (int i=0; i<LazyList.size(_listeners); i++) ((Listener)LazyList.get(_listeners, i)).add(event); } } /* ------------------------------------------------------------ */ /** remove a parent child relationship * @param parent * @param child * @param relationship */ private void remove(Object parent, Object child, String relationship) { if (LOG.isDebugEnabled()) LOG.debug("Container "+parent+" - "+child+" as "+relationship); if (_listeners!=null) { Relationship event=new Relationship(this,parent,child,relationship); for (int i=0; i<LazyList.size(_listeners); i++) ((Listener)LazyList.get(_listeners, i)).remove(event); } } /* ------------------------------------------------------------ */ /** A Container event. * @see Listener */ public static class Relationship { private final WeakReference<Object> _parent; private final WeakReference<Object> _child; private String _relationship; private Container _container; private Relationship(Container container, Object parent,Object child, String relationship) { _container=container; _parent=new WeakReference<Object>(parent); _child=new WeakReference<Object>(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); } }