org.apache.commons.jxpath.ri
Class JXPathContextReferenceImpl

java.lang.Object
  org.apache.commons.jxpath.JXPathContext
      org.apache.commons.jxpath.ri.JXPathContextReferenceImpl

public class JXPathContextReferenceImpl

extends JXPathContext

The reference implementation of JXPathContext.

Version:

$Revision: 1.43 $ $Date: 2004/04/04 23:16:23 $

Author:

Dmitri Plotnikov

Field Summary

private static int	CLEANUP_THRESHOLD
private static int	cleanupCount
private static java.util.Map	compiled
private static Compiler	COMPILER
private Pointer	contextPointer
protected NamespaceResolver	namespaceResolver
private static java.util.Vector	nodeFactories
private static NodePointerFactory[]	nodeFactoryArray
private Pointer	rootPointer
static boolean	USE_SOFT_CACHE Change this to false to disable soft caching of CompiledExpressions.

Fields inherited from class org.apache.commons.jxpath.JXPathContext

contextBean, decimalFormats, factory, functions, idManager, keyManager, parentContext, vars

Constructor Summary

protected	JXPathContextReferenceImpl(JXPathContext parentContext, java.lang.Object contextBean)
	JXPathContextReferenceImpl(JXPathContext parentContext, java.lang.Object contextBean, Pointer contextPointer)

Method Summary

static void	addNodePointerFactory(NodePointerFactory factory) Call this with a custom NodePointerFactory to add support for additional types of objects.
static java.lang.Object	allocateConditionally(java.lang.String className, java.lang.String existenceCheckClassName) Checks if existenceCheckClass exists on the class path.
private void	checkSimplePath(Expression expr) Checks if the path follows the JXPath restrictions on the type of path that can be passed to create...
private Expression	compileExpression(java.lang.String xpath)
protected CompiledExpression	compilePath(java.lang.String xpath) Overridden by each concrete implementation of JXPathContext to perform compilation.
private static void	createNodeFactoryArray()
Pointer	createPath(java.lang.String xpath) Creates missing elements of the path by invoking an AbstractFactory, which should first be installed on the context by calling "setFactory".
Pointer	createPath(java.lang.String xpath, Expression expr)
Pointer	createPathAndSetValue(java.lang.String xpath, Expression expr, java.lang.Object value)
Pointer	createPathAndSetValue(java.lang.String xpath, java.lang.Object value) The same as setValue, except it creates intermediate elements of the path by invoking an AbstractFactory, which should first be installed on the context by calling "setFactory".
EvalContext	getAbsoluteRootContext()
private NodePointer	getAbsoluteRootPointer()
protected Compiler	getCompiler() Returns a static instance of TreeCompiler.
Pointer	getContextPointer() Returns a Pointer for the context bean.
private EvalContext	getEvalContext()
Function	getFunction(QName functionName, java.lang.Object[] parameters)
Pointer	getNamespaceContextPointer() Returns the namespace context pointer set with setNamespaceContextPointer() or, if none has been specified, the context pointer otherwise.
NamespaceResolver	getNamespaceResolver()
java.lang.String	getNamespaceURI(java.lang.String prefix) Given a prefix, returns a registered namespace URI.
static NodePointerFactory[]	getNodePointerFactories()
Pointer	getPointer(java.lang.String xpath) Traverses the xpath and returns a Pointer.
Pointer	getPointer(java.lang.String xpath, Expression expr)
JXPathContext	getRelativeContext(Pointer pointer) Returns a JXPathContext that is relative to the current JXPathContext.
java.lang.Object	getValue(java.lang.String xpath) Traverses the xpath and returns the resulting object.
java.lang.Object	getValue(java.lang.String xpath, java.lang.Class requiredType) Calls getValue(xpath), converts the result to the required type and returns the result of the conversion.
java.lang.Object	getValue(java.lang.String xpath, Expression expr)
java.lang.Object	getValue(java.lang.String xpath, Expression expr, java.lang.Class requiredType)
NodePointer	getVariablePointer(QName name)
java.util.Iterator	iterate(java.lang.String xpath) Traverses the xpath and returns a Iterator of all results found for the path.
java.util.Iterator	iterate(java.lang.String xpath, Expression expr)
java.util.Iterator	iteratePointers(java.lang.String xpath) Traverses the xpath and returns an Iterator of Pointers.
java.util.Iterator	iteratePointers(java.lang.String xpath, Expression expr)
void	registerNamespace(java.lang.String prefix, java.lang.String namespaceURI) Registers a namespace prefix.
void	removeAll(java.lang.String xpath) Removes all elements of the object graph described by the xpath.
void	removeAll(java.lang.String xpath, Expression expr)
void	removePath(java.lang.String xpath) Removes the element of the object graph described by the xpath.
void	removePath(java.lang.String xpath, Expression expr)
void	setNamespaceContextPointer(Pointer pointer) Namespace prefixes can be defined implicitly by specifying a pointer to a context where the namespaces are defined.
void	setValue(java.lang.String xpath, Expression expr, java.lang.Object value)
private Pointer	setValue(java.lang.String xpath, Expression expr, java.lang.Object value, boolean create)
void	setValue(java.lang.String xpath, java.lang.Object value) Modifies the value of the property described by the supplied xpath.

Methods inherited from class org.apache.commons.jxpath.JXPathContext

compile, getContextBean, getDecimalFormatSymbols, getFactory, getFunctions, getIdentityManager, getKeyManager, getLocale, getParentContext, getPointerByID, getPointerByKey, getVariables, isLenient, newContext, newContext, selectNodes, selectSingleNode, setDecimalFormatSymbols, setFactory, setFunctions, setIdentityManager, setKeyManager, setLenient, setLocale, setVariables

Methods inherited from class java.lang.Object

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

Field Detail

USE_SOFT_CACHE

public static final boolean USE_SOFT_CACHE

Change this to false to disable soft caching of CompiledExpressions.

See Also:

Constant Field Values

COMPILER

private static final Compiler COMPILER

compiled

private static java.util.Map compiled

cleanupCount

private static int cleanupCount

nodeFactories

private static java.util.Vector nodeFactories

nodeFactoryArray

private static NodePointerFactory[] nodeFactoryArray

rootPointer

private Pointer rootPointer

contextPointer

private Pointer contextPointer

namespaceResolver

protected NamespaceResolver namespaceResolver

CLEANUP_THRESHOLD

private static final int CLEANUP_THRESHOLD

See Also:

Constant Field Values

Constructor Detail

JXPathContextReferenceImpl

protected JXPathContextReferenceImpl(JXPathContext parentContext,
                                     java.lang.Object contextBean)

JXPathContextReferenceImpl

public JXPathContextReferenceImpl(JXPathContext parentContext,
                                  java.lang.Object contextBean,
                                  Pointer contextPointer)

Method Detail

createNodeFactoryArray

private static void createNodeFactoryArray()

addNodePointerFactory

public static void addNodePointerFactory(NodePointerFactory factory)

Call this with a custom NodePointerFactory to add support for additional types of objects. Make sure the factory returns a name that puts it in the right position on the list of factories.

getNodePointerFactories

public static NodePointerFactory[] getNodePointerFactories()

getCompiler

protected Compiler getCompiler()

Returns a static instance of TreeCompiler. Override this to return an aternate compiler.

compilePath

protected CompiledExpression compilePath(java.lang.String xpath)

Description copied from class: JXPathContext

Overridden by each concrete implementation of JXPathContext to perform compilation. Is called by compile().

Specified by:

compilePath in class JXPathContext

compileExpression

private Expression compileExpression(java.lang.String xpath)

getValue

public java.lang.Object getValue(java.lang.String xpath)

Traverses the xpath and returns the resulting object. Primitive types are wrapped into objects.

Specified by:

getValue in class JXPathContext

getValue

public java.lang.Object getValue(java.lang.String xpath,
                                 Expression expr)

getValue

public java.lang.Object getValue(java.lang.String xpath,
                                 java.lang.Class requiredType)

Calls getValue(xpath), converts the result to the required type and returns the result of the conversion.

Specified by:

getValue in class JXPathContext

getValue

public java.lang.Object getValue(java.lang.String xpath,
                                 Expression expr,
                                 java.lang.Class requiredType)

iterate

public java.util.Iterator iterate(java.lang.String xpath)

Traverses the xpath and returns a Iterator of all results found for the path. If the xpath matches no properties in the graph, the Iterator will not be null.

Specified by:

iterate in class JXPathContext

iterate

public java.util.Iterator iterate(java.lang.String xpath,
                                  Expression expr)

getPointer

public Pointer getPointer(java.lang.String xpath)

Description copied from class: JXPathContext

Traverses the xpath and returns a Pointer. A Pointer provides easy access to a property. If the xpath matches no properties in the graph, the pointer will be null.

Specified by:

getPointer in class JXPathContext

getPointer

public Pointer getPointer(java.lang.String xpath,
                          Expression expr)

setValue

public void setValue(java.lang.String xpath,
                     java.lang.Object value)

Description copied from class: JXPathContext

Modifies the value of the property described by the supplied xpath. Will throw an exception if one of the following conditions occurs:

• The xpath does not in fact describe an existing property
• The property is not writable (no public, non-static set method)

Specified by:

setValue in class JXPathContext

setValue

public void setValue(java.lang.String xpath,
                     Expression expr,
                     java.lang.Object value)

createPath

public Pointer createPath(java.lang.String xpath)

Description copied from class: JXPathContext

Creates missing elements of the path by invoking an AbstractFactory, which should first be installed on the context by calling "setFactory".

Will throw an exception if the AbstractFactory fails to create an instance for a path element.

Specified by:

createPath in class JXPathContext

createPath

public Pointer createPath(java.lang.String xpath,
                          Expression expr)

createPathAndSetValue

public Pointer createPathAndSetValue(java.lang.String xpath,
                                     java.lang.Object value)

Description copied from class: JXPathContext

The same as setValue, except it creates intermediate elements of the path by invoking an AbstractFactory, which should first be installed on the context by calling "setFactory".

Will throw an exception if one of the following conditions occurs:

• Elements of the xpath aleady exist, but the path does not in fact describe an existing property
• The AbstractFactory fails to create an instance for an intermediate element.
• The property is not writable (no public, non-static set method)

Specified by:

createPathAndSetValue in class JXPathContext

createPathAndSetValue

public Pointer createPathAndSetValue(java.lang.String xpath,
                                     Expression expr,
                                     java.lang.Object value)

setValue

private Pointer setValue(java.lang.String xpath,
                         Expression expr,
                         java.lang.Object value,
                         boolean create)

checkSimplePath

private void checkSimplePath(Expression expr)

Checks if the path follows the JXPath restrictions on the type of path that can be passed to create... methods.

iteratePointers

public java.util.Iterator iteratePointers(java.lang.String xpath)

Traverses the xpath and returns an Iterator of Pointers. A Pointer provides easy access to a property. If the xpath matches no properties in the graph, the Iterator be empty, but not null.

Specified by:

iteratePointers in class JXPathContext

iteratePointers

public java.util.Iterator iteratePointers(java.lang.String xpath,
                                          Expression expr)

removePath

public void removePath(java.lang.String xpath)

Description copied from class: JXPathContext

Removes the element of the object graph described by the xpath.

Specified by:

removePath in class JXPathContext

removePath

public void removePath(java.lang.String xpath,
                       Expression expr)

removeAll

public void removeAll(java.lang.String xpath)

Description copied from class: JXPathContext

Removes all elements of the object graph described by the xpath.

Specified by:

removeAll in class JXPathContext

removeAll

public void removeAll(java.lang.String xpath,
                      Expression expr)

getRelativeContext

public JXPathContext getRelativeContext(Pointer pointer)

Description copied from class: JXPathContext

Returns a JXPathContext that is relative to the current JXPathContext. The supplied pointer becomes the context pointer of the new context. The relative context inherits variables, extension functions, locale etc from the parent context.

Specified by:

getRelativeContext in class JXPathContext

getContextPointer

public Pointer getContextPointer()

Description copied from class: JXPathContext

Returns a Pointer for the context bean.

Specified by:

getContextPointer in class JXPathContext

getAbsoluteRootPointer

private NodePointer getAbsoluteRootPointer()

getEvalContext

private EvalContext getEvalContext()

getAbsoluteRootContext

public EvalContext getAbsoluteRootContext()

getVariablePointer

public NodePointer getVariablePointer(QName name)

getFunction

public Function getFunction(QName functionName,
                            java.lang.Object[] parameters)

registerNamespace

public void registerNamespace(java.lang.String prefix,
                              java.lang.String namespaceURI)

Description copied from class: JXPathContext

Registers a namespace prefix.

Overrides:

registerNamespace in class JXPathContext

Parameters:

prefix - A namespace prefix

namespaceURI - A URI for that prefix

getNamespaceURI

public java.lang.String getNamespaceURI(java.lang.String prefix)

Description copied from class: JXPathContext

Given a prefix, returns a registered namespace URI. If the requested prefix was not defined explicitly using the registerNamespace method, JXPathContext will then check the context node to see if the prefix is defined there. See setNamespaceContextPointer.

Overrides:

getNamespaceURI in class JXPathContext

Parameters:

prefix - The namespace prefix to look up

Returns:

namespace URI or null if the prefix is undefined.

setNamespaceContextPointer

public void setNamespaceContextPointer(Pointer pointer)

Description copied from class: JXPathContext

Namespace prefixes can be defined implicitly by specifying a pointer to a context where the namespaces are defined. By default, NamespaceContextPointer is the same as the Context Pointer, see getContextPointer()

Overrides:

setNamespaceContextPointer in class JXPathContext

getNamespaceContextPointer

public Pointer getNamespaceContextPointer()

Description copied from class: JXPathContext

Returns the namespace context pointer set with setNamespaceContextPointer() or, if none has been specified, the context pointer otherwise.

Overrides:

getNamespaceContextPointer in class JXPathContext

Returns:

The namespace context pointer.

getNamespaceResolver

public NamespaceResolver getNamespaceResolver()

allocateConditionally

public static java.lang.Object allocateConditionally(java.lang.String className,
                                                     java.lang.String existenceCheckClassName)

Checks if existenceCheckClass exists on the class path. If so, allocates an instance of the specified class, otherwise returns null.