com.werken.xpath

Class ContextSupport

public class ContextSupport extends 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
FunctiongetFunction(String name)
Retrieve a named function

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

ObjectgetVariableValue(String name)
Resolve a variable binding

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

voidsetFunctionContext(FunctionContext functionContext)
Set the FunctionContext implementation
voidsetNamespaceContext(NamespaceContext nsContext)
Set the NamespaceContext implementation
voidsetVariableContext(VariableContext variableContext)
Set the VariableContext implementation
StringtranslateNamespacePrefix(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 Detail

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 Detail

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: ContextSupport

getVariableValue

public Object getVariableValue(String name)
Resolve a variable binding

Retrieve the currently bound value of the named variable, or null if no such binding exists. Delegates to the VariableContext implementation provided, if any.

Parameters: name The name of the variable sought.

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

See Also: ContextSupport

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: ContextSupport

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