javax.jcr.util
Class TraversingItemVisitor

java.lang.Object
  javax.jcr.util.TraversingItemVisitor

All Implemented Interfaces:

ItemVisitor

Direct Known Subclasses:

TraversingItemVisitor.Default

public abstract class TraversingItemVisitor
extends java.lang.Object
implements ItemVisitor

An implementation of ItemVisitor.

TraversingItemVisitor is an abstract utility class which allows to easily traverse an Item hierarchy.

TraversingItemVisitor makes use of the Visitor Pattern as described in the book 'Design Patterns' by the Gang Of Four (Gamma et al.).

Tree traversal is done observing the left-to-right order of child Items if such an order is supported and exists.

Nested Class Summary

static class

TraversingItemVisitor.Default Convenience class providing default implementations of the abstract methods of TraversingItemVisitor.

Field Summary

protected boolean	breadthFirst Indicates if traversal should be done in a breadth-first manner rather than depth-first (which is the default).
private int	currentLevel Used to track hierarchy level of item currently being processed.
private java.util.LinkedList	currentQueue Queues used to implement breadth-first traversal.
protected int	maxLevel The 0-based level up to which the hierarchy should be traversed (if it's -1, the hierarchy will be traversed until there are no more children of the current item).
private java.util.LinkedList	nextQueue

Constructor Summary

TraversingItemVisitor()
Constructs a new instance of this class.

TraversingItemVisitor(boolean breadthFirst)
Constructs a new instance of this class.

TraversingItemVisitor(boolean breadthFirst, int maxLevel)
Constructs a new instance of this class.

Method Summary

protected abstract void	entering(Node node, int level) Implement this method to add behavior performed before a Node is visited.
protected abstract void	entering(Property property, int level) Implement this method to add behavior performed before a Property is visited.
protected abstract void	leaving(Node node, int level) Implement this method to add behavior performed after a Node is visited.
protected abstract void	leaving(Property property, int level) Implement this method to add behavior performed after a Property is visited.
void	visit(Node node) Called when the Visitor is passed to a Node.
void	visit(Property property) Called when the Visitor is passed to a Property.

Methods inherited from class java.lang.Object

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

Field Detail

breadthFirst

protected final boolean breadthFirst

Indicates if traversal should be done in a breadth-first manner rather than depth-first (which is the default).

maxLevel

protected final int maxLevel

The 0-based level up to which the hierarchy should be traversed (if it's -1, the hierarchy will be traversed until there are no more children of the current item).

currentQueue

private java.util.LinkedList currentQueue

Queues used to implement breadth-first traversal.

nextQueue

private java.util.LinkedList nextQueue

currentLevel

private int currentLevel

Used to track hierarchy level of item currently being processed.

Constructor Detail

TraversingItemVisitor

public TraversingItemVisitor()

Constructs a new instance of this class.

The tree of Items will be traversed in a depth-first manner (default behavior).

TraversingItemVisitor

public TraversingItemVisitor(boolean breadthFirst)

Constructs a new instance of this class.

Parameters:

breadthFirst - if breadthFirst is true then traversal is done in a breadth-first manner; otherwise it is done in a depth-first manner (which is the default behavior).

TraversingItemVisitor

public TraversingItemVisitor(boolean breadthFirst,
                             int maxLevel)

Constructs a new instance of this class.

Parameters:

breadthFirst - if breadthFirst is true then traversal is done in a breadth-first manner; otherwise it is done in a depth-first manner (which is the default behavior).

maxLevel - the 0-based level up to which the hierarchy should be traversed (if it's -1, the hierarchy will be traversed until there are no more children of the current item).

Method Detail

entering

protected abstract void entering(Property property,
                                 int level)
                          throws RepositoryException

Implement this method to add behavior performed before a Property is visited.

Parameters:

property - the Property that is accepting this visitor.

level - hierarchy level of this property (the root node starts at level 0).

Throws:

RepositoryException - if an error occurs.

entering

protected abstract void entering(Node node,
                                 int level)
                          throws RepositoryException

Implement this method to add behavior performed before a Node is visited.

Parameters:

node - the Node that is accepting this visitor.

level - hierarchy level of this node (the root node starts at level 0).

Throws:

RepositoryException - if an error occurs.

leaving

protected abstract void leaving(Property property,
                                int level)
                         throws RepositoryException

Implement this method to add behavior performed after a Property is visited.

Parameters:

property - the Property that is accepting this visitor.

level - hierarchy level of this property (the root node starts at level 0).

Throws:

RepositoryException - if an error occurs.

leaving

protected abstract void leaving(Node node,
                                int level)
                         throws RepositoryException

Implement this method to add behavior performed after a Node is visited.

Parameters:

node - the Node that is accepting this visitor.

level - hierarchy level of this node (the root node starts at level 0).

Throws:

RepositoryException - if an error occurs.

visit

public void visit(Property property)
           throws RepositoryException

Called when the Visitor is passed to a Property.

It calls TraversingItemVisitor.entering(Property, int) followed by TraversingItemVisitor.leaving(Property, int). Implement these abstract methods to specify behavior on 'arrival at' and 'after leaving' the Property.

If this method throws, the visiting process is aborted.

Specified by:

visit in interface ItemVisitor

Parameters:

property - the Property that is accepting this visitor.

Throws:

RepositoryException - if an error occurs.

visit

public void visit(Node node)
           throws RepositoryException

Called when the Visitor is passed to a Node.

It calls TraversingItemVisitor.entering(Node, int) followed by TraversingItemVisitor.leaving(Node, int). Implement these abstract methods to specify behavior on 'arrival at' and 'after leaving' the Node.

If this method throws, the visiting process is aborted.

Specified by:

visit in interface ItemVisitor

Parameters:

node - the Node that is accepting this visitor.

Throws:

RepositoryException - if an error occurs.