Package org.dellroad.stuff.java

Class GraphCloneRegistry

java.lang.Object

org.dellroad.stuff.java.GraphCloneRegistry

public class GraphCloneRegistry
extends Object

A registry for copies of GraphCloneable objects used during graph cloning operations. A graph clone of a graph of objects is a deep copy without duplicates and preserving reference topology.

See GraphCloneable for a complete description.

See Also:

• GraphCloneable

Constructor Summary

Constructors

Constructor	Description
GraphCloneRegistry()

Method Summary

Modifier and Type	Method	Description
<T extends GraphCloneable> T	getGraphClone(T value)	Get the unique clone of a given value during a graph clone operation, creating it if necessary.
void	setGraphClone(GraphCloneable clone)	Register the given clone as the unique instance associated with the object currently being cloned.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

GraphCloneRegistry

public GraphCloneRegistry()

Method Details

getGraphClone

public <T extends GraphCloneable> T getGraphClone(T value)

Get the unique clone of a given value during a graph clone operation, creating it if necessary.

If the value has already been cloned and registered with this instance, it is returned. Otherwise, a new clone of value is created and registered with this instance by invoking value.createGraphClone(), and then returned.

If the value is null, null is returned.

Type Parameters:

T - object type

Parameters:

value - original value

Returns:

unique clone of value, or null if value is null

Throws:

IllegalStateException - if value.createGraphClone() fails to invoke setGraphClone()

IllegalStateException - if value.createGraphClone() invokes setGraphClone() more than once

IllegalStateException - if value.createGraphClone() fails to invoke setGraphClone() prior to recursing on other GraphCloneable fields

setGraphClone

public void setGraphClone(GraphCloneable clone)

Register the given clone as the unique instance associated with the object currently being cloned.

The "object currently being cloned" is the GraphCloneable object associated with the top-most invocation of GraphCloneable.createGraphClone() on the Java execution stack.

This method should only be invoked within implementations of GraphCloneable.createGraphClone().

Parameters:

clone - the clone associated with the current object being graph cloned; may be null (but that would be weird)

Throws:

IllegalStateException - if the current thread is not executing within an invocation of GraphCloneable.createGraphClone()