org.apache.commons.configuration2.tree

Class NodeHandlerDecorator<T>

java.lang.Object

org.apache.commons.configuration2.tree.NodeHandlerDecorator<T>

Type Parameters:

T - the type of the nodes supported by this handler

All Implemented Interfaces:

NodeHandler<T>

public abstract class NodeHandlerDecorator<T>
extends Object
implements NodeHandler<T>

An abstract base class for decorators of a NodeHandler.

This class implements all methods of the NodeHandler interface by delegating to another instance. This is convenient if specific functionality of a NodeHandler is to be adapted for a special use case. Concrete sub classes have to implement the getDecoratedNodeHandler() method to provide the underlying handler.

Since:

2.0

Constructor Summary

Constructors

Constructor and Description
NodeHandlerDecorator()

Method Summary

Modifier and Type	Method and Description
Set<String>	getAttributes(T node) Returns an unmodifiable set with the names of all attributes of the specified node.
Object	getAttributeValue(T node, String name) Returns the value of the specified attribute from the given node.
T	getChild(T node, int index) Returns the child with the given index of the specified node.
List<T>	getChildren(T node) Returns an unmodifiable list with all children of the specified node.
List<T>	getChildren(T node, String name) Returns an unmodifiable list of all children of the specified node with the given name.
int	getChildrenCount(T node, String name) Returns the number of children of the specified node with the given name.
protected abstract NodeHandler<T>	getDecoratedNodeHandler() Returns the NodeHandler object that is decorated by this instance.
<C> List<T>	getMatchingChildren(T node, NodeMatcher<C> matcher, C criterion) Returns an unmodifiable list of all children of the specified node which are matched by the passed in NodeMatcher against the provided criterion.
<C> int	getMatchingChildrenCount(T node, NodeMatcher<C> matcher, C criterion) Returns the number of children of the specified node which are matched by the given NodeMatcher.
T	getParent(T node) Returns the parent of the specified node.
T	getRootNode() Returns the root node of the underlying hierarchy.
Object	getValue(T node) Returns the value of the specified node.
boolean	hasAttributes(T node) Returns a flag whether the passed in node has any attributes.
int	indexOfChild(T parent, T child) Returns the index of the given child node in the list of children of its parent.
boolean	isDefined(T node) Checks whether the specified node is defined.
String	nodeName(T node) Returns the name of the specified node

Methods inherited from class java.lang.Object

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

Constructor Detail

NodeHandlerDecorator

public NodeHandlerDecorator()

Method Detail

nodeName

public String nodeName(T node)

Description copied from interface: NodeHandler

Returns the name of the specified node

Specified by:

nodeName in interface NodeHandler<T>

Parameters:

node - the node

Returns:

the name of this node

getValue

public Object getValue(T node)

Description copied from interface: NodeHandler

Returns the value of the specified node.

Specified by:

getValue in interface NodeHandler<T>

Parameters:

node - the node

Returns:

the value of this node

getParent

public T getParent(T node)

Description copied from interface: NodeHandler

Returns the parent of the specified node.

Specified by:

getParent in interface NodeHandler<T>

Parameters:

node - the node

Returns:

the parent node

getChildren

public List<T> getChildren(T node)

Description copied from interface: NodeHandler

Returns an unmodifiable list with all children of the specified node.

Specified by:

getChildren in interface NodeHandler<T>

Parameters:

node - the node

Returns:

a list with the child nodes of this node

getMatchingChildren

public <C> List<T> getMatchingChildren(T node,
                                       NodeMatcher<C> matcher,
                                       C criterion)

Description copied from interface: NodeHandler

Returns an unmodifiable list of all children of the specified node which are matched by the passed in NodeMatcher against the provided criterion. This method allows for advanced queries on a node's children.

Specified by:

getMatchingChildren in interface NodeHandler<T>

Type Parameters:

C - the type of the criterion

Parameters:

node - the node

matcher - the NodeMatcher defining filter criteria

criterion - the criterion to be matched against; this object is passed to the NodeMatcher

Returns:

a list with all children matched by the matcher

getMatchingChildrenCount

public <C> int getMatchingChildrenCount(T node,
                                        NodeMatcher<C> matcher,
                                        C criterion)

Description copied from interface: NodeHandler

Returns the number of children of the specified node which are matched by the given NodeMatcher. This is a more generic version of NodeHandler.getChildrenCount(Object, String). It allows checking for arbitrary filter conditions.

Specified by:

getMatchingChildrenCount in interface NodeHandler<T>

Type Parameters:

C - the type of the criterion

Parameters:

node - the node

matcher - the NodeMatcher

criterion - the criterion to be passed to the NodeMatcher

Returns:

the number of matched children

getChildren

public List<T> getChildren(T node,
                           String name)

Description copied from interface: NodeHandler

Returns an unmodifiable list of all children of the specified node with the given name.

Specified by:

getChildren in interface NodeHandler<T>

Parameters:

node - the node

name - the name of the desired child nodes

Returns:

a list with all children with the given name

getChild

public T getChild(T node,
                  int index)

Description copied from interface: NodeHandler

Returns the child with the given index of the specified node.

Specified by:

getChild in interface NodeHandler<T>

Parameters:

node - the node

index - the index (0-based)

Returns:

the child with the given index

indexOfChild

public int indexOfChild(T parent,
                        T child)

Description copied from interface: NodeHandler

Returns the index of the given child node in the list of children of its parent. This method is the opposite operation of NodeHandler.getChild(Object, int). This method returns 0 if the given node is the first child node with this name, 1 for the second child node and so on. If the node has no parent node or if it is an attribute, -1 is returned.

Specified by:

indexOfChild in interface NodeHandler<T>

Parameters:

parent - the parent node

child - a child node whose index is to be retrieved

Returns:

the index of this child node

getChildrenCount

public int getChildrenCount(T node,
                            String name)

Description copied from interface: NodeHandler

Returns the number of children of the specified node with the given name. This method exists for performance reasons: for some node implementations it may be by far more efficient to count the children than to query a list of all children and determine its size. A concrete implementation can choose the most efficient way to determine the number of children. If a child name is passed in, only the children with this name are taken into account. If the name null is passed, the total number of children must be returned.

Specified by:

getChildrenCount in interface NodeHandler<T>

Parameters:

node - the node

name - the name of the children in question (can be null for all children)

Returns:

the number of the selected children

getAttributes

public Set<String> getAttributes(T node)

Description copied from interface: NodeHandler

Returns an unmodifiable set with the names of all attributes of the specified node.

Specified by:

getAttributes in interface NodeHandler<T>

Parameters:

node - the node

Returns:

a set with the names of all attributes of this node

hasAttributes

public boolean hasAttributes(T node)

Description copied from interface: NodeHandler

Returns a flag whether the passed in node has any attributes.

Specified by:

hasAttributes in interface NodeHandler<T>

Parameters:

node - the node

Returns:

a flag whether this node has any attributes

getAttributeValue

public Object getAttributeValue(T node,
                                String name)

Description copied from interface: NodeHandler

Returns the value of the specified attribute from the given node. If a concrete NodeHandler supports attributes with multiple values, result might be a collection.

Specified by:

getAttributeValue in interface NodeHandler<T>

Parameters:

node - the node

name - the name of the attribute

Returns:

the value of this attribute

isDefined

public boolean isDefined(T node)

Description copied from interface: NodeHandler

Checks whether the specified node is defined. Nodes are "defined" if they contain any data, e.g. a value, or attributes, or defined children.

Specified by:

isDefined in interface NodeHandler<T>

Parameters:

node - the node to test

Returns:

a flag whether the passed in node is defined

getRootNode

public T getRootNode()

Description copied from interface: NodeHandler

Returns the root node of the underlying hierarchy.

Specified by:

getRootNode in interface NodeHandler<T>

Returns:

the current root node

getDecoratedNodeHandler

protected abstract NodeHandler<T> getDecoratedNodeHandler()

Returns the NodeHandler object that is decorated by this instance. All method calls are delegated to this object.

Returns:

the decorated NodeHandler