org.apache.commons.jxpath.ri.model
Class NodePointer

java.lang.Object
  extended by org.apache.commons.jxpath.ri.model.NodePointer
All Implemented Interfaces:
java.io.Serializable, java.lang.Cloneable, java.lang.Comparable, Pointer
Direct Known Subclasses:
CollectionPointer, ContainerPointer, DOMAttributePointer, DOMNodePointer, JDOMAttributePointer, JDOMNamespacePointer, JDOMNodePointer, LangAttributePointer, NamespacePointer, PropertyOwnerPointer, PropertyPointer, VariablePointer

public abstract class NodePointer
extends java.lang.Object
implements Pointer

Common superclass for Pointers of all kinds. A NodePointer maps to a deterministic XPath that represents the location of a node in an object graph. This XPath uses only simple axes: child, namespace and attribute and only simple, context-independent predicates.

Version:
$Revision: 668329 $ $Date: 2008-06-16 16:59:48 -0500 (Mon, 16 Jun 2008) $
Author:
Dmitri Plotnikov
See Also:
Serialized Form

Field Summary
protected  int index
          Index for this NodePointer
protected  java.util.Locale locale
          Locale
protected  NodePointer parent
          Parent pointer
static java.lang.String UNKNOWN_NAMESPACE
          Constant to indicate unknown namespace
static int WHOLE_COLLECTION
          Whole collection index.
 
Constructor Summary
protected NodePointer(NodePointer parent)
          Create a new NodePointer.
protected NodePointer(NodePointer parent, java.util.Locale locale)
          Create a new NodePointer.
 
Method Summary
 java.lang.String asPath()
          Returns an XPath that maps to this Pointer.
 NodeIterator attributeIterator(QName qname)
          Returns a NodeIterator that iterates over all attributes of the current node matching the supplied node name (could have a wildcard).
 NodeIterator childIterator(NodeTest test, boolean reverse, NodePointer startWith)
          Returns a NodeIterator that iterates over all children or all children that match the given NodeTest, starting with the specified one.
 java.lang.Object clone()
          Clone this NodePointer.
abstract  int compareChildNodePointers(NodePointer pointer1, NodePointer pointer2)
          Compares two child NodePointers and returns a positive number, zero or a positive number according to the order of the pointers.
 int compareTo(java.lang.Object object)
           
 NodePointer createAttribute(JXPathContext context, QName name)
          Called to create a non-existing attribute
 NodePointer createChild(JXPathContext context, QName name, int index)
          Called by a child pointer when it needs to create a parent object for a non-existent collection element.
 NodePointer createChild(JXPathContext context, QName name, int index, java.lang.Object value)
          Called by a child pointer if that child needs to assign the value supplied in the createPath(context, value) call to a non-existent node.
 NodePointer createPath(JXPathContext context)
          Called by a child pointer when it needs to create a parent object.
 NodePointer createPath(JXPathContext context, java.lang.Object value)
          Called directly by JXPathContext.
protected  java.lang.String escape(java.lang.String string)
          Return a string escaping single and double quotes.
protected  AbstractFactory getAbstractFactory(JXPathContext context)
          Get the AbstractFactory associated with the specified JXPathContext.
abstract  java.lang.Object getBaseValue()
          Returns the value represented by the pointer before indexing.
protected  java.lang.String getDefaultNamespaceURI()
          Get the default ns uri
abstract  java.lang.Object getImmediateNode()
          Returns the object the pointer points to; does not convert it to a "canonical" type.
 NodePointer getImmediateParentPointer()
          Get the immediate parent pointer.
 NodePointer getImmediateValuePointer()
           
 int getIndex()
          If the pointer represents a collection, the index identifies an element of that collection.
abstract  int getLength()
          If the pointer represents a collection (or collection element), returns the length of the collection.
 java.util.Locale getLocale()
          If the Pointer has a parent, returns the parent's locale; otherwise returns the locale specified when this Pointer was created.
abstract  QName getName()
          Returns the name of this node.
 NamespaceResolver getNamespaceResolver()
          Get the NamespaceResolver associated with this NodePointer.
 java.lang.String getNamespaceURI()
          Returns the namespace URI associated with this Pointer.
 java.lang.String getNamespaceURI(java.lang.String prefix)
          Decodes a namespace prefix to the corresponding URI.
 java.lang.Object getNode()
          Returns the object the pointer points to; does not convert it to a "canonical" type.
 NodeSet getNodeSetByKey(JXPathContext context, java.lang.String key, java.lang.Object value)
          Find a NodeSet by key/value.
 java.lang.Object getNodeValue()
          Deprecated. 1.1 Please use getNode()
 NodePointer getParent()
          Get the parent pointer.
 Pointer getPointerByID(JXPathContext context, java.lang.String id)
          Locates a node by ID.
 Pointer getPointerByKey(JXPathContext context, java.lang.String key, java.lang.String value)
          Locates a node by key and value.
 java.lang.Object getRootNode()
          Get the root node.
 java.lang.Object getValue()
          By default, returns getNode(), can be overridden to return a "canonical" value, like for instance a DOM element should return its string value.
 NodePointer getValuePointer()
          If this pointer manages a transparent container, like a variable, this method returns the pointer to the contents.
 boolean isActual()
          An actual pointer points to an existing part of an object graph, even if it is null.
 boolean isAttribute()
          Returns true if the pointer represents the "attribute::" axis.
abstract  boolean isCollection()
          Returns true if the value of the pointer is an array or a Collection.
 boolean isContainer()
          If true, this node is auxiliary and can only be used as an intermediate in the chain of pointers.
protected  boolean isDefaultNamespace(java.lang.String prefix)
          Returns true if the supplied prefix represents the default namespace in the context of the current node.
 boolean isLanguage(java.lang.String lang)
          Check whether our locale matches the specified language.
abstract  boolean isLeaf()
          If true, this node does not have children
 boolean isNode()
          Deprecated. Please use !isContainer()
 boolean isRoot()
          Returns true if this Pointer has no parent.
 NodeIterator namespaceIterator()
          Returns a NodeIterator that iterates over all namespaces of the value currently pointed at.
 NodePointer namespacePointer(java.lang.String namespace)
          Returns a NodePointer for the specified namespace.
static NodePointer newChildNodePointer(NodePointer parent, QName name, java.lang.Object bean)
          Allocates an new child NodePointer by iterating through all installed NodePointerFactories until it finds one that can create a pointer.
static NodePointer newNodePointer(QName name, java.lang.Object bean, java.util.Locale locale)
          Allocates an entirely new NodePointer by iterating through all installed NodePointerFactories until it finds one that can create a pointer.
 void printPointerChain()
          Print internal structure of a pointer for debugging
 void remove()
          Remove the node of the object graph this pointer points to.
 void setAttribute(boolean attribute)
          Set to true if the pointer represents the "attribute::" axis.
 void setIndex(int index)
          Set the index of this NodePointer.
 void setNamespaceResolver(NamespaceResolver namespaceResolver)
          Set the NamespaceResolver for this NodePointer.
abstract  void setValue(java.lang.Object value)
          Converts the value to the required type and changes the corresponding object to that value.
 boolean testNode(NodeTest test)
          Checks if this Pointer matches the supplied NodeTest.
 java.lang.String toString()
           
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

WHOLE_COLLECTION

public static final int WHOLE_COLLECTION
Whole collection index.

See Also:
Constant Field Values

UNKNOWN_NAMESPACE

public static final java.lang.String UNKNOWN_NAMESPACE
Constant to indicate unknown namespace

See Also:
Constant Field Values

index

protected int index
Index for this NodePointer


parent

protected NodePointer parent
Parent pointer


locale

protected java.util.Locale locale
Locale

Constructor Detail

NodePointer

protected NodePointer(NodePointer parent)
Create a new NodePointer.

Parameters:
parent - Pointer

NodePointer

protected NodePointer(NodePointer parent,
                      java.util.Locale locale)
Create a new NodePointer.

Parameters:
parent - Pointer
locale - Locale
Method Detail

newNodePointer

public static NodePointer newNodePointer(QName name,
                                         java.lang.Object bean,
                                         java.util.Locale locale)
Allocates an entirely new NodePointer by iterating through all installed NodePointerFactories until it finds one that can create a pointer.

Parameters:
name - QName
bean - Object
locale - Locale
Returns:
NodePointer

newChildNodePointer

public static NodePointer newChildNodePointer(NodePointer parent,
                                              QName name,
                                              java.lang.Object bean)
Allocates an new child NodePointer by iterating through all installed NodePointerFactories until it finds one that can create a pointer.

Parameters:
parent - pointer
name - QName
bean - Object
Returns:
NodePointer

getNamespaceResolver

public NamespaceResolver getNamespaceResolver()
Get the NamespaceResolver associated with this NodePointer.

Returns:
NamespaceResolver

setNamespaceResolver

public void setNamespaceResolver(NamespaceResolver namespaceResolver)
Set the NamespaceResolver for this NodePointer.

Parameters:
namespaceResolver - NamespaceResolver

getParent

public NodePointer getParent()
Get the parent pointer.

Returns:
NodePointer

getImmediateParentPointer

public NodePointer getImmediateParentPointer()
Get the immediate parent pointer.

Returns:
NodePointer

setAttribute

public void setAttribute(boolean attribute)
Set to true if the pointer represents the "attribute::" axis.

Parameters:
attribute - boolean

isAttribute

public boolean isAttribute()
Returns true if the pointer represents the "attribute::" axis.

Returns:
boolean

isRoot

public boolean isRoot()
Returns true if this Pointer has no parent.

Returns:
boolean

isLeaf

public abstract boolean isLeaf()
If true, this node does not have children

Returns:
boolean

isNode

public boolean isNode()
Deprecated. Please use !isContainer()

Learn whether this pointer is considered to be a node.

Returns:
boolean

isContainer

public boolean isContainer()
If true, this node is auxiliary and can only be used as an intermediate in the chain of pointers.

Returns:
boolean

getIndex

public int getIndex()
If the pointer represents a collection, the index identifies an element of that collection. The default value of index is WHOLE_COLLECTION, which just means that the pointer is not indexed at all. Note: the index on NodePointer starts with 0, not 1.

Returns:
int

setIndex

public void setIndex(int index)
Set the index of this NodePointer.

Parameters:
index - int

isCollection

public abstract boolean isCollection()
Returns true if the value of the pointer is an array or a Collection.

Returns:
boolean

getLength

public abstract int getLength()
If the pointer represents a collection (or collection element), returns the length of the collection. Otherwise returns 1 (even if the value is null).

Returns:
int

getValue

public java.lang.Object getValue()
By default, returns getNode(), can be overridden to return a "canonical" value, like for instance a DOM element should return its string value.

Specified by:
getValue in interface Pointer
Returns:
Object value

getValuePointer

public NodePointer getValuePointer()
If this pointer manages a transparent container, like a variable, this method returns the pointer to the contents. Only an auxiliary (non-node) pointer can (and should) return a value pointer other than itself. Note that you probably don't want to override getValuePointer() directly. Override the getImmediateValuePointer() method instead. The getValuePointer() method is calls getImmediateValuePointer() and, if the result is not this, invokes getValuePointer() recursively. The idea here is to open all nested containers. Let's say we have a container within a container within a container. The getValuePointer() method should then open all those containers and return the pointer to the ultimate contents. It does so with the above recursion.

Returns:
NodePointer

getImmediateValuePointer

public NodePointer getImmediateValuePointer()
Returns:
NodePointer is either this or a pointer for the immediately contained value.
See Also:
getValuePointer()

isActual

public boolean isActual()
An actual pointer points to an existing part of an object graph, even if it is null. A non-actual pointer represents a part that does not exist at all. For instance consider the pointer "/address/street". If both address and street are not null, the pointer is actual. If address is not null, but street is null, the pointer is still actual. If address is null, the pointer is not actual. (In JavaBeans) if address is not a property of the root bean, a Pointer for this path cannot be obtained at all - actual or otherwise.

Returns:
boolean

getName

public abstract QName getName()
Returns the name of this node. Can be null.

Returns:
QName

getBaseValue

public abstract java.lang.Object getBaseValue()
Returns the value represented by the pointer before indexing. So, if the node represents an element of a collection, this method returns the collection itself.

Returns:
Object value

getNodeValue

public java.lang.Object getNodeValue()
Deprecated. 1.1 Please use getNode()

Returns the object the pointer points to; does not convert it to a "canonical" type.

Returns:
Object node value

getNode

public java.lang.Object getNode()
Returns the object the pointer points to; does not convert it to a "canonical" type. Opens containers, properties etc and returns the ultimate contents.

Specified by:
getNode in interface Pointer
Returns:
Object node

getRootNode

public java.lang.Object getRootNode()
Get the root node.

Specified by:
getRootNode in interface Pointer
Returns:
Object value of this pointer's root (top parent).

getImmediateNode

public abstract java.lang.Object getImmediateNode()
Returns the object the pointer points to; does not convert it to a "canonical" type.

Returns:
Object node

setValue

public abstract void setValue(java.lang.Object value)
Converts the value to the required type and changes the corresponding object to that value.

Specified by:
setValue in interface Pointer
Parameters:
value - the value to set

compareChildNodePointers

public abstract int compareChildNodePointers(NodePointer pointer1,
                                             NodePointer pointer2)
Compares two child NodePointers and returns a positive number, zero or a positive number according to the order of the pointers.

Parameters:
pointer1 - first pointer to be compared
pointer2 - second pointer to be compared
Returns:
int per Java comparison conventions

testNode

public boolean testNode(NodeTest test)
Checks if this Pointer matches the supplied NodeTest.

Parameters:
test - the NodeTest to execute
Returns:
true if a match

createPath

public NodePointer createPath(JXPathContext context,
                              java.lang.Object value)
Called directly by JXPathContext. Must create path and set value.

Parameters:
context - the owning JXPathContext
value - the new value to set
Returns:
created NodePointer

remove

public void remove()
Remove the node of the object graph this pointer points to.


createPath

public NodePointer createPath(JXPathContext context)
Called by a child pointer when it needs to create a parent object. Must create an object described by this pointer and return a new pointer that properly describes the new object.

Parameters:
context - the owning JXPathContext
Returns:
created NodePointer

createChild

public NodePointer createChild(JXPathContext context,
                               QName name,
                               int index,
                               java.lang.Object value)
Called by a child pointer if that child needs to assign the value supplied in the createPath(context, value) call to a non-existent node. This method may have to expand the collection in order to assign the element.

Parameters:
context - the owning JXPathCOntext
name - the QName at which a child should be created
index - child index.
value - node value to set
Returns:
created NodePointer

createChild

public NodePointer createChild(JXPathContext context,
                               QName name,
                               int index)
Called by a child pointer when it needs to create a parent object for a non-existent collection element. It may have to expand the collection, then create an element object and return a new pointer describing the newly created element.

Parameters:
context - the owning JXPathCOntext
name - the QName at which a child should be created
index - child index.
Returns:
created NodePointer

createAttribute

public NodePointer createAttribute(JXPathContext context,
                                   QName name)
Called to create a non-existing attribute

Parameters:
context - the owning JXPathCOntext
name - the QName at which an attribute should be created
Returns:
created NodePointer

getLocale

public java.util.Locale getLocale()
If the Pointer has a parent, returns the parent's locale; otherwise returns the locale specified when this Pointer was created.

Returns:
Locale for this NodePointer

isLanguage

public boolean isLanguage(java.lang.String lang)
Check whether our locale matches the specified language.

Parameters:
lang - String language to check
Returns:
true if the selected locale name starts with the specified prefix lang, case-insensitive.

childIterator

public NodeIterator childIterator(NodeTest test,
                                  boolean reverse,
                                  NodePointer startWith)
Returns a NodeIterator that iterates over all children or all children that match the given NodeTest, starting with the specified one.

Parameters:
test - NodeTest to filter children
reverse - specified iteration direction
startWith - the NodePointer to start with
Returns:
NodeIterator

attributeIterator

public NodeIterator attributeIterator(QName qname)
Returns a NodeIterator that iterates over all attributes of the current node matching the supplied node name (could have a wildcard). May return null if the object does not support the attributes.

Parameters:
qname - the attribute name to test
Returns:
NodeIterator

namespaceIterator

public NodeIterator namespaceIterator()
Returns a NodeIterator that iterates over all namespaces of the value currently pointed at. May return null if the object does not support the namespaces.

Returns:
NodeIterator

namespacePointer

public NodePointer namespacePointer(java.lang.String namespace)
Returns a NodePointer for the specified namespace. Will return null if namespaces are not supported. Will return UNKNOWN_NAMESPACE if there is no such namespace.

Parameters:
namespace - incoming namespace
Returns:
NodePointer for namespace

getNamespaceURI

public java.lang.String getNamespaceURI(java.lang.String prefix)
Decodes a namespace prefix to the corresponding URI.

Parameters:
prefix - prefix to decode
Returns:
String uri

getNamespaceURI

public java.lang.String getNamespaceURI()
Returns the namespace URI associated with this Pointer.

Returns:
String uri

isDefaultNamespace

protected boolean isDefaultNamespace(java.lang.String prefix)
Returns true if the supplied prefix represents the default namespace in the context of the current node.

Parameters:
prefix - the prefix to check
Returns:
true if prefix is default

getDefaultNamespaceURI

protected java.lang.String getDefaultNamespaceURI()
Get the default ns uri

Returns:
String uri

getPointerByID

public Pointer getPointerByID(JXPathContext context,
                              java.lang.String id)
Locates a node by ID.

Parameters:
context - JXPathContext owning context
id - String id
Returns:
Pointer found

getPointerByKey

public Pointer getPointerByKey(JXPathContext context,
                               java.lang.String key,
                               java.lang.String value)
Locates a node by key and value.

Parameters:
context - owning JXPathContext
key - key to search for
value - value to match
Returns:
Pointer found

getNodeSetByKey

public NodeSet getNodeSetByKey(JXPathContext context,
                               java.lang.String key,
                               java.lang.Object value)
Find a NodeSet by key/value.

Parameters:
context - owning JXPathContext
key - key to search for
value - value to match
Returns:
NodeSet found

asPath

public java.lang.String asPath()
Returns an XPath that maps to this Pointer.

Specified by:
asPath in interface Pointer
Returns:
String xpath expression

clone

public java.lang.Object clone()
Clone this NodePointer.

Specified by:
clone in interface Pointer
Overrides:
clone in class java.lang.Object
Returns:
cloned NodePointer

toString

public java.lang.String toString()
Overrides:
toString in class java.lang.Object

compareTo

public int compareTo(java.lang.Object object)
Specified by:
compareTo in interface java.lang.Comparable

printPointerChain

public void printPointerChain()
Print internal structure of a pointer for debugging


escape

protected java.lang.String escape(java.lang.String string)
Return a string escaping single and double quotes.

Parameters:
string - string to treat
Returns:
string with any necessary changes made.

getAbstractFactory

protected AbstractFactory getAbstractFactory(JXPathContext context)
Get the AbstractFactory associated with the specified JXPathContext.

Parameters:
context - JXPathContext
Returns:
AbstractFactory


Copyright © 2001-2011 Apache Software Foundation. All Rights Reserved.