org.apache.xalan.lib

## Class Extensions

- java.lang.Object
- - org.apache.xalan.lib.Extensions

    public class Extensions
    extends java.lang.Object

This class contains many of the Xalan-supplied extensions. It is accessed by specifying a namespace URI as follows:

        xmlns:xalan="http://xml.apache.org/xalan"

Usage:

### Method Summary

Methods
`static Node` `checkEnvironment(ExpressionContext myContext)` Return a Node of basic debugging information from the EnvironmentCheck utility about the Java environment.
`static NodeList` `difference(NodeList nl1, NodeList nl2)` Returns the difference between two node-sets.
`static NodeList` `distinct(NodeList nl)` Returns node-set containing distinct string values.
`static XObject` `evaluate(ExpressionContext myContext, java.lang.String xpathExpr)` Returns the result of evaluating the argument as a string containing an XPath expression.
`static boolean` `hasSameNodes(NodeList nl1, NodeList nl2)` Returns true if both node-sets contain the same set of nodes.
`static NodeList` `intersection(NodeList nl1, NodeList nl2)` Returns the intersection of two node-sets.
`static NodeSet` `nodeset(ExpressionContext myProcessor, java.lang.Object rtf)` This method is an extension that implements as a Xalan extension the node-set function also found in xt and saxon.
`static NodeList` `tokenize(java.lang.String toTokenize)` Returns a NodeSet containing one text node for each token in the first argument.
`static NodeList` `tokenize(java.lang.String toTokenize, java.lang.String delims)` Returns a NodeSet containing one text node for each token in the first argument.

### Methods inherited from class java.lang.Object

`equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

### Method Detail

#### nodeset

    public static NodeSet nodeset(ExpressionContext myProcessor,
                  java.lang.Object rtf)

This method is an extension that implements as a Xalan extension the node-set function also found in xt and saxon. If the argument is a Result Tree Fragment, then `nodeset` returns a node-set consisting of a single root node as described in section 11.1 of the XSLT 1.0 Recommendation. If the argument is a node-set, `nodeset` returns a node-set. If the argument is a string, number, or boolean, then `nodeset` returns a node-set consisting of a single root node with a single text node child that is the result of calling the XPath string() function on the passed parameter. If the argument is anything else, then a node-set is returned consisting of a single root node with a single text node child that is the result of calling the java `toString()` method on the passed argument. Most of the actual work here is done in `MethodResolver` and `XRTreeFrag`.

Parameters:
  `myProcessor` - Context passed by the extension processor
  `rtf` - Argument in the stylesheet to the nodeset extension function NEEDSDOC ($objectName$) @return

#### intersection

    public static NodeList intersection(NodeList nl1,
                        NodeList nl2)

Returns the intersection of two node-sets.

Parameters:
  `nl1` - NodeList for first node-set
  `nl2` - NodeList for second node-set
Returns:
  a NodeList containing the nodes in nl1 that are also in nl2 Note: The usage of this extension function in the xalan namespace is deprecated. Please use the same function in the EXSLT sets extension (http://exslt.org/sets).

#### difference

    public static NodeList difference(NodeList nl1,
                      NodeList nl2)

Returns the difference between two node-sets.

Parameters:
  `nl1` - NodeList for first node-set
  `nl2` - NodeList for second node-set
Returns:
  a NodeList containing the nodes in nl1 that are not in nl2 Note: The usage of this extension function in the xalan namespace is deprecated. Please use the same function in the EXSLT sets extension (http://exslt.org/sets).

#### distinct

    public static NodeList distinct(NodeList nl)

Returns node-set containing distinct string values.

Parameters:
  `nl` - NodeList for node-set
Returns:
  a NodeList with nodes from nl containing distinct string values. In other words, if more than one node in nl contains the same string value, only include the first such node found. Note: The usage of this extension function in the xalan namespace is deprecated. Please use the same function in the EXSLT sets extension (http://exslt.org/sets).

#### hasSameNodes

    public static boolean hasSameNodes(NodeList nl1,
                       NodeList nl2)

Returns true if both node-sets contain the same set of nodes.

Parameters:
  `nl1` - NodeList for first node-set
  `nl2` - NodeList for second node-set
Returns:
  true if nl1 and nl2 contain exactly the same set of nodes.

#### evaluate

    public static XObject evaluate(ExpressionContext myContext,
                   java.lang.String xpathExpr)
                            throws SAXNotSupportedException

Returns the result of evaluating the argument as a string containing an XPath expression. Used where the XPath expression is not known until run-time. The expression is evaluated as if the run-time value of the argument appeared in place of the evaluate function call at compile time.

Parameters:
  `myContext` - an `ExpressionContext` passed in by the extension mechanism. This must be an XPathContext.
  `xpathExpr` - The XPath expression to be evaluated.
Returns:
  the XObject resulting from evaluating the XPath
Throws:
  `SAXNotSupportedException` - Note: The usage of this extension function in the xalan namespace is deprecated. Please use the same function in the EXSLT dynamic extension (http://exslt.org/dynamic).

#### tokenize

    public static NodeList tokenize(java.lang.String toTokenize,
                    java.lang.String delims)

Returns a NodeSet containing one text node for each token in the first argument. Delimiters are specified in the second argument. Tokens are determined by a call to `StringTokenizer`. If the first argument is an empty string or contains only delimiters, the result will be an empty NodeSet. Contributed to XalanJ1 by Benoit Cerrina.

Parameters:
  `toTokenize` - The string to be split into text tokens.
  `delims` - The delimiters to use.
Returns:
  a NodeSet as described above.

#### tokenize

    public static NodeList tokenize(java.lang.String toTokenize)

Returns a NodeSet containing one text node for each token in the first argument. Delimiters are whitespace. That is, the delimiters that are used are tab ( ), linefeed ( ), return ( ), and space ( ). Tokens are determined by a call to `StringTokenizer`. If the first argument is an empty string or contains only delimiters, the result will be an empty NodeSet. Contributed to XalanJ1 by Benoit Cerrina.

Parameters:
  `toTokenize` - The string to be split into text tokens.
Returns:
  a NodeSet as described above.

#### checkEnvironment

    public static Node checkEnvironment(ExpressionContext myContext)

Return a Node of basic debugging information from the EnvironmentCheck utility about the Java environment.

Simply calls the `EnvironmentCheck` utility to grab info about the Java environment and CLASSPATH, etc., and then returns the resulting Node. Stylesheets can then maniuplate this data or simply xsl:copy-of the Node. Note that we first attempt to load the more advanced org.apache.env.Which utility by reflection; only if that fails to we still use the internal version. Which is available from http://xml.apache.org/commons/.

We throw a WrappedRuntimeException in the unlikely case that reading information from the environment throws us an exception. (Is this really the best thing to do?)

Parameters:
  `myContext` - an `ExpressionContext` passed in by the extension mechanism. This must be an XPathContext.
Returns:
  a Node as described above.