com.sun.xml.ws.api.pipe.TubeCloner Maven / Gradle / Ivy
package com.sun.xml.ws.api.pipe;
import java.util.HashMap;
import java.util.Map;
/**
* Clones the whole pipeline.
*
*
* 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 master2copy = new HashMap();
/*package*/ TubeCloner() {
}
/**
* Invoked by a client of a tube to clone the whole pipeline.
*
*
* {@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.
*
*
* This method is for {@link Tube} implementations, not for users.
*
*
* 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.
*
*
* (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 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.
*
*
* 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);
}
}