org.camunda.bpm.engine.impl.tree
Class ReferenceWalker<T>

java.lang.Object
  org.camunda.bpm.engine.impl.tree.ReferenceWalker<T>

Direct Known Subclasses:

ActivityInstanceWalker, SingleReferenceWalker

public abstract class ReferenceWalker<T>
extends Object

A walker for walking through an object reference structure (e.g. an execution tree). Any visited element can have any number of following elements. The elements are visited with a breadth-first approach: The walker maintains a list of next elements to which it adds a new elements at the end whenever it has visited an element. The walker stops when it encounters an element that fulfills the given ReferenceWalker.WalkCondition.

Subclasses define the type of objects and provide the walking behavior.

Author:

Thorben Lindhauer

Nested Class Summary

static class	ReferenceWalker.NullCondition<S>
static interface	ReferenceWalker.WalkCondition<S>

Field Summary

protected List<T>	currentElements
protected List<TreeVisitor<T>>	postVisitor
protected List<TreeVisitor<T>>	preVisitor

Constructor Summary

ReferenceWalker(T initialElement)

Method Summary

ReferenceWalker<T>	addPostVisitor(TreeVisitor<T> collector)
ReferenceWalker<T>	addPreVisitor(TreeVisitor<T> collector)
T	getCurrentElement()
protected abstract Collection<T>	nextElements()
T	walkUntil()
T	walkUntil(ReferenceWalker.WalkCondition<T> condition)
T	walkWhile()
T	walkWhile(ReferenceWalker.WalkCondition<T> condition)

Methods inherited from class java.lang.Object

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

Field Detail

currentElements

protected List<T> currentElements

preVisitor

protected List<TreeVisitor<T>> preVisitor

postVisitor

protected List<TreeVisitor<T>> postVisitor

Constructor Detail

ReferenceWalker

public ReferenceWalker(T initialElement)

Method Detail

nextElements

protected abstract Collection<T> nextElements()

addPreVisitor

public ReferenceWalker<T> addPreVisitor(TreeVisitor<T> collector)

addPostVisitor

public ReferenceWalker<T> addPostVisitor(TreeVisitor<T> collector)

walkWhile

public T walkWhile()

walkUntil

public T walkUntil()

walkWhile

public T walkWhile(ReferenceWalker.WalkCondition<T> condition)

walkUntil

public T walkUntil(ReferenceWalker.WalkCondition<T> condition)

getCurrentElement

public T getCurrentElement()