/*
* Copyright (c) 2005, 2006, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package com.sun.xml.internal.ws.api.pipe;
import java.util.HashMap;
import java.util.Map;
/**
* Clones the whole pipeline.
*
* <p>
* Since {@link Tube}s may form an arbitrary directed graph, someone needs
* to keep track of isomorphism for a clone to happen correctly. This class
* serves that role.
*
* @author Kohsuke Kawaguchi
*/
public class TubeCloner {
// Pipe to pipe, or tube to tube
protected final Map<Object,Object> master2copy = new HashMap<Object,Object>();
/*package*/ TubeCloner() {
}
/**
* Invoked by a client of a tube to clone the whole pipeline.
*
* <p>
* {@link Tube}s implementing the {@link Tube#copy(TubeCloner)} method
* shall use {@link #copy(Tube)} method.
*
* @param p
* The entry point of a pipeline to be copied. must not be null.
* @return
* The cloned pipeline. Always non-null.
*/
public static Tube clone(Tube p) {
// we often want to downcast TubeCloner to PipeCloner,
// so let's create PipeCloner to make that possible
return new PipeCloner().copy(p);
}
/**
* Invoked by a {@link Tube#copy(TubeCloner)} implementation
* to copy a reference to another pipe.
*
* <p>
* This method is for {@link Tube} implementations, not for users.
*
* <p>
* If the given tube is already copied for this cloning episode,
* this method simply returns that reference. Otherwise it copies
* a tube, make a note, and returns a copied tube. This additional
* step ensures that a graph is cloned isomorphically correctly.
*
* <p>
* (Think about what happens when a graph is A->B, A->C, B->D, and C->D
* if you don't have this step.)
*
* @param t
* The tube to be copied.
* @return
* The cloned tube. Always non-null.
*/
public <T extends Tube> T copy(T t) {
Tube r = (Tube)master2copy.get(t);
if(r==null) {
r = t.copy(this);
// the pipe must puts its copy to the map by itself
assert master2copy.get(t)==r : "the tube must call the add(...) method to register itself before start copying other pipes, but "+t +" hasn't done so";
}
return (T)r;
}
/**
* This method must be called from within the copy constructor
* to notify that the copy was created.
*
* <p>
* When your pipe has references to other pipes,
* it's particularly important to call this method
* before you start copying the pipes you refer to,
* or else there's a chance of inifinite loop.
*/
public void add(Tube original, Tube copy) {
assert !master2copy.containsKey(original);
assert original!=null && copy!=null;
master2copy.put(original,copy);
}
}