Java example source code file (ExpressionContext.java)

This example Java source code file (ExpressionContext.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

dom, errorlistener, expressioncontext, nodeiterator, string, xobject

The ExpressionContext.java Java example source code

/*
 * reserved comment block
 * DO NOT REMOVE OR ALTER!
 */
/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: ExpressionContext.java,v 1.2.4.1 2005/09/10 19:34:03 jeffsuttor Exp $
 */
package com.sun.org.apache.xalan.internal.extensions;

import javax.xml.transform.ErrorListener;

import com.sun.org.apache.xpath.internal.objects.XObject;
import org.w3c.dom.Node;
import org.w3c.dom.traversal.NodeIterator;

/**
 * An object that implements this interface can supply
 * information about the current XPath expression context.
 */
public interface ExpressionContext
{

  /**
   * Get the current context node.
   * @return The current context node.
   */
  public Node getContextNode();

  /**
   * Get the current context node list.
   * @return An iterator for the current context list, as
   * defined in XSLT.
   */
  public NodeIterator getContextNodes();

  /**
   * Get the error listener.
   * @return The registered error listener.
   */
  public ErrorListener getErrorListener();

  /**
   * Get the value of a node as a number.
   * @param n Node to be converted to a number.  May be null.
   * @return value of n as a number.
   */
  public double toNumber(Node n);

  /**
   * Get the value of a node as a string.
   * @param n Node to be converted to a string.  May be null.
   * @return value of n as a string, or an empty string if n is null.
   */
  public String toString(Node n);

  /**
   * Get a variable based on it's qualified name.
   *
   * @param qname The qualified name of the variable.
   *
   * @return The evaluated value of the variable.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public XObject getVariableOrParam(com.sun.org.apache.xml.internal.utils.QName qname)
            throws javax.xml.transform.TransformerException;

  /**
   * Get the XPathContext that owns this ExpressionContext.
   *
   * Note: exslt:function requires the XPathContext to access
   * the variable stack and TransformerImpl.
   *
   * @return The current XPathContext.
   * @throws javax.xml.transform.TransformerException
   */
  public com.sun.org.apache.xpath.internal.XPathContext getXPathContext()
            throws javax.xml.transform.TransformerException;

}