PackageFunctions (Apache Commons JXPath 1.4-SNAPSHOT API)

java.lang.Object
- org.apache.commons.jxpath.PackageFunctions

All Implemented Interfaces:

Functions
```
public class PackageFunctions
extends Object
implements Functions
```
Extension functions provided by Java classes. The class prefix specified in the constructor is used when a constructor or a static method is called. Usually, a class prefix is a package name (hence the name of this class). Let's say, we declared a PackageFunction like this:
```
     new PackageFunctions("java.util.", "util")
 
```
We can now use XPaths like:

"util:Date.new()"

Equivalent to new java.util.Date()

"util:Collections.singleton('foo')"

Equivalent to java.util.Collections.singleton("foo")

"util:substring('foo', 1, 2)"

Equivalent to "foo".substring(1, 2). Note that in this case, the class prefix is not used. JXPath does not check that the first parameter of the function (the method target) is in fact a member of the package described by this PackageFunctions object.

If the first argument of a method or constructor is ExpressionContext, the expression context in which the function is evaluated is passed to the method.

There is one PackageFunctions object registered by default with each JXPathContext. It does not have a namespace and uses no class prefix. The existence of this object allows us to use XPaths like: "java.util.Date.new()" and "length('foo')" without the explicit registration of any extension functions.
Version:

$Revision: 916559 $ $Date: 2010-02-26 04:55:46 +0100 (Fr, 26 Feb 2010) $

Author:

Dmitri Plotnikov

Constructor Summary

Constructors
Constructor and Description

PackageFunctions(String classPrefix, String namespace)
Create a new PackageFunctions.

Constructors
Constructor and Description
`PackageFunctions(String classPrefix, String namespace)` Create a new PackageFunctions.

Method Summary

Methods
Modifier and Type	Method and Description
`Function`	`getFunction(String namespace, String name, Object[] parameters)` Returns a `Function`, if found, for the specified namespace, name and parameter types.
`Set`	`getUsedNamespaces()` Returns the namespace specified in the constructor

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - PackageFunctions
```
public PackageFunctions(String classPrefix,
                String namespace)
```
    Create a new PackageFunctions.
    
    Parameters:
    classPrefix - class prefix
    namespace - namespace String
- Method Detail
  - getUsedNamespaces
```
public Set getUsedNamespaces()
```
    Returns the namespace specified in the constructor
    
    Specified by:
    
    getUsedNamespaces in interface Functions
    
    Returns:
    (singleton) namespace Set
  - getFunction
```
public Function getFunction(String namespace,
                   String name,
                   Object[] parameters)
```
    Returns a Function, if found, for the specified namespace, name and parameter types.
    Specified by:
    
    getFunction in interface Functions
    
    Parameters:
    namespace - - if it is not the same as specified in the construction, this method returns null
    name - - name of the method, which can one these forms:
    
    methodname, if invoking a method on an object passed as the first parameter
    
    Classname.new, if looking for a constructor
    
    subpackage.subpackage.Classname.new, if looking for a constructor in a subpackage
    
    Classname.methodname, if looking for a static method
    
    subpackage.subpackage.Classname.methodname, if looking for a static method of a class in a subpackage
    parameters - Object[] of parameters
    
    Returns:
    a MethodFunction, a ConstructorFunction or null if no function is found

Class PackageFunctions

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

PackageFunctions

Method Detail

getUsedNamespaces

getFunction