org.macroing.cit.java.util.node

Class AbstractReflectiveNodeHierarchicalVisitor

java.lang.Object

org.macroing.cit.java.util.node.AbstractReflectiveNodeHierarchicalVisitor

All Implemented Interfaces:

NodeHierarchicalVisitor

public abstract class AbstractReflectiveNodeHierarchicalVisitor
extends java.lang.Object
implements NodeHierarchicalVisitor

An abstract class that delegates method calls for visitEnter(Node) and visitLeave(Node).

It is completely driven by the Java Reflection API. This means that you can create a subclass containing any number of overloaded methods, provided that the one and only parameter argument must be assignment compatible to the interface Node.

The names of the overloaded methods must be either visitEnter or visitLeave.

It doesn't matter whether you return boolean or something completely different. But, note however, that, if you want to be able to skip entering any child or sibling Nodes, you must provide a boolean return type and return false. Otherwise, true is implicitly chosen.

Any access modifier may be used, as they will all be accepted.

Since:

1.0.0

Author:

Jörgen Lundgren

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractReflectiveNodeHierarchicalVisitor() Constructs a new AbstractReflectiveNodeHierarchicalVisitor instance.

Method Summary

Modifier and Type	Method and Description
boolean	visitEnter(Node node) Called by a concrete Node implementation.
boolean	visitLeave(Node node) Called by a concrete Node implementation.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractReflectiveNodeHierarchicalVisitor

protected AbstractReflectiveNodeHierarchicalVisitor()

Constructs a new AbstractReflectiveNodeHierarchicalVisitor instance.

Method Detail

visitEnter

public final boolean visitEnter(Node node)

Called by a concrete Node implementation.

It should happen soon after its accept(NodeHierarchicalVisitor) method has been called, with this AbstractReflectiveNodeHierarchicalVisitor as its parameter argument.

If node is null, a NullPointerException will be thrown.

If node could not be traversed by this AbstractReflectiveNodeHierarchicalVisitor, a NodeTraversalException will be thrown.

To visit nodes child Nodes, return true, false otherwise.

The implementation provided by this class, will attempt to delegate all calls to overloaded methods with a parameter argument that is assignment compatible to Node. If no overloaded method can be found for node, true will be returned. But, if it can be found, it will be called. If the return type of the overloaded method is boolean, the value of that boolean will be returned by this method. If it is not boolean, true will be returned by default. The overloaded method may have any access modifier assigned to it. So private methods will work.

Specified by:

visitEnter in interface NodeHierarchicalVisitor

Parameters:

node - the Node to enter

Returns:

true if, and only if, nodes child Nodes should be visited, false otherwise

Throws:

NodeTraversalException - thrown if, and only if, node could not be traversed by this AbstractReflectiveNodeHierarchicalVisitor

java.lang.NullPointerException - thrown if, and only if, node is null

visitLeave

public final boolean visitLeave(Node node)

Called by a concrete Node implementation.

It should happen just before its accept(NodeHierarchicalVisitor) method returns. Actually, it should be the result returned by that method.

If node is null, a NullPointerException will be thrown.

If node could not be traversed by this AbstractReflectiveNodeHierarchicalVisitor, a NodeTraversalException will be thrown.

To visit nodes sibling Nodes, return true, false otherwise.

The implementation provided by this class, will attempt to delegate all calls to overloaded methods with a parameter argument that is assignment compatible to Node. If no overloaded method can be found for node, true will be returned. But, if it can be found, it will be called. If the return type of the overloaded method is boolean, the value of that boolean will be returned by this method. If it is not boolean, true will be returned by default. The overloaded method may have any access modifier assigned to it. So private methods will work.

Specified by:

visitLeave in interface NodeHierarchicalVisitor

Parameters:

node - the Node to leave

Returns:

true if, and only if, nodes sibling Nodes should be visited, false otherwise

Throws:

NodeTraversalException - thrown if, and only if, node could not be traversed by this AbstractReflectiveNodeHierarchicalVisitor

java.lang.NullPointerException - should be thrown if, and only if, node is null