com.werken.xpath

Class ContextSupport


public class ContextSupport
extends java.lang.Object

ContextSupport maintains information to aid in the execution of the XPath against a context node.

It separates the knowledge of functions, variables and namespace-bindings from the context node to be walked.

Author:
bob mcwhirter (bob @ werken.com)

Constructor Summary

ContextSupport()
Construct a semantically empty ContextSupport
ContextSupport(NamespaceContext nsContext, FunctionContext functionContext, VariableContext variableContext)
Construct a semantically initialized ContextSupport

Method Summary

Function
getFunction(String name)
Retrieve a named function

Retrieve the named function object, or null if no such function exists.

Object
getVariableValue(String name)
Resolve a variable binding

Retrieve the currently bound value of the named variable, or null if no such binding exists.

void
setFunctionContext(FunctionContext functionContext)
Set the FunctionContext implementation
void
setNamespaceContext(NamespaceContext nsContext)
Set the NamespaceContext implementation
void
setVariableContext(VariableContext variableContext)
Set the VariableContext implementation
String
translateNamespacePrefix(String prefix)
Translate a namespace prefix into a URI

Using the NamespaceContext implementation, translate the prefix used in a component of an XPath into its expanded namespace URI.

Constructor Details

ContextSupport

public ContextSupport()
Construct a semantically empty ContextSupport


ContextSupport

public ContextSupport(NamespaceContext nsContext,
                      FunctionContext functionContext,
                      VariableContext variableContext)
Construct a semantically initialized ContextSupport

Parameters:
nsContext - The NamespaceContext implementation
functionContext - The FunctionContext implementation
variableContext - The VariableContext implementation

Method Details

getFunction

public Function getFunction(String name)
Retrieve a named function

Retrieve the named function object, or null if no such function exists. Delegates to the FunctionContext implementation provided, if any.

Parameters:
name - The name of the function sought.

Returns:
The Function matching the specified name.

See Also:
setFunctionContext(FunctionContext)


getVariableValue

public Object getVariableValue(String name)

Parameters:
name - The name of the variable sought.

Returns:
The currently bound value of the variable, or null.

See Also:
setVariableContext(VariableContext)


setFunctionContext

public void setFunctionContext(FunctionContext functionContext)
Set the FunctionContext implementation

Parameters:
functionContext - The FunctionContext implementation


setNamespaceContext

public void setNamespaceContext(NamespaceContext nsContext)
Set the NamespaceContext implementation

Parameters:
nsContext - The NamespaceContext implementation


setVariableContext

public void setVariableContext(VariableContext variableContext)
Set the VariableContext implementation

Parameters:
variableContext - The FunctionContext implementation


translateNamespacePrefix

public String translateNamespacePrefix(String prefix)
Translate a namespace prefix into a URI

Using the NamespaceContext implementation, translate the prefix used in a component of an XPath into its expanded namespace URI.

Parameters:
prefix - The namespace prefix

Returns:
The URI matching the prefix

See Also:
setNamespaceContext(NamespaceContext)


Copyright B) 2000 bob mcwhirter and The Werken & Sons Company. All Rights Reserved.