/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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.
 */
/*
 * $Id$
 */

package org.apache.xalan.lib;

import javax.xml.transform.SourceLocator;

import org.apache.xalan.extensions.ExpressionContext;
import org.apache.xml.dtm.ref.DTMNodeProxy;

import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

/**
 * <code>NodeInfo</code> defines a set of XSLT extension functions to be
 * used from stylesheets.
 *
 * @author <a href="mailto:ovidiu@cup.hp.com">Ovidiu Predescu</a>
 * @since May 24, 2001
 */
public class NodeInfo
{
  /**
   * <code>systemId</code> returns the system id of the current
   * context node.
   *
   * @param context an <code>ExpressionContext</code> value
   * @return a <code>String</code> value
   */
  public static String systemId(ExpressionContext context)
  {
    Node contextNode = context.getContextNode();
    int nodeHandler = ((DTMNodeProxy)contextNode).getDTMNodeNumber();
    SourceLocator locator = ((DTMNodeProxy)contextNode).getDTM()
      .getSourceLocatorFor(nodeHandler);

    if (locator != null)
      return locator.getSystemId();
    else
      return null;
  }

  /**
   * <code>systemId</code> returns the system id of the node passed as
   * argument. If a node set is passed as argument, the system id of
   * the first node in the set is returned.
   *
   * @param nodeList a <code>NodeList</code> value
   * @return a <code>String</code> value
   */
  public static String systemId(NodeList nodeList)
  {
    if (nodeList == null || nodeList.getLength() == 0)
      return null;
    
    Node node = nodeList.item(0);
    int nodeHandler = ((DTMNodeProxy)node).getDTMNodeNumber();
    SourceLocator locator = ((DTMNodeProxy)node).getDTM()
      .getSourceLocatorFor(nodeHandler);

    if (locator != null)
      return locator.getSystemId();
    else
      return null;
  }

  /**
   * <code>publicId</code> returns the public identifier of the current
   * context node.
   * 
   * Xalan does not currently record this value, and will return null.
   *
   * @param context an <code>ExpressionContext</code> value
   * @return a <code>String</code> value
   */
  public static String publicId(ExpressionContext context)
  {
    Node contextNode = context.getContextNode();
    int nodeHandler = ((DTMNodeProxy)contextNode).getDTMNodeNumber();
    SourceLocator locator = ((DTMNodeProxy)contextNode).getDTM()
      .getSourceLocatorFor(nodeHandler);

    if (locator != null)
      return locator.getPublicId();
    else
      return null;
  }

  /**
   * <code>publicId</code> returns the public identifier of the node passed as
   * argument. If a node set is passed as argument, the public identifier of
   * the first node in the set is returned.
   * 
   * Xalan does not currently record this value, and will return null.
   *
   * @param nodeList a <code>NodeList</code> value
   * @return a <code>String</code> value
   */
  public static String publicId(NodeList nodeList)
  {
    if (nodeList == null || nodeList.getLength() == 0)
      return null;
    
    Node node = nodeList.item(0);
    int nodeHandler = ((DTMNodeProxy)node).getDTMNodeNumber();
    SourceLocator locator = ((DTMNodeProxy)node).getDTM()
      .getSourceLocatorFor(nodeHandler);

    if (locator != null)
      return locator.getPublicId();
    else
      return null;
  }

  /**
   * <code>lineNumber</code> returns the line number of the current
   * context node.
   * 
   * NOTE: Xalan does not normally record location information for each node. 
   * To obtain it, you must set the custom TrAX attribute 
   * "http://xml.apache.org/xalan/features/source_location"
   * true in the TransformerFactory before generating the Transformer and executing
   * the stylesheet. Storage cost per node will be noticably increased in this mode.
   *
   * @param context an <code>ExpressionContext</code> value
   * @return an <code>int</code> value. This may be -1 to indicate that the
   * line number is not known.
   */
  public static int lineNumber(ExpressionContext context)
  {
    Node contextNode = context.getContextNode();
    int nodeHandler = ((DTMNodeProxy)contextNode).getDTMNodeNumber();
    SourceLocator locator = ((DTMNodeProxy)contextNode).getDTM()
      .getSourceLocatorFor(nodeHandler);

    if (locator != null)
      return locator.getLineNumber();
    else
      return -1;
  }

  /**
   * <code>lineNumber</code> returns the line number of the node
   * passed as argument. If a node set is passed as argument, the line
   * number of the first node in the set is returned.
   *
   * NOTE: Xalan does not normally record location information for each node. 
   * To obtain it, you must set the custom TrAX attribute 
   * "http://xml.apache.org/xalan/features/source_location"
   * true in the TransformerFactory before generating the Transformer and executing
   * the stylesheet. Storage cost per node will be noticably increased in this mode.
   *
   * @param nodeList a <code>NodeList</code> value
   * @return an <code>int</code> value. This may be -1 to indicate that the
   * line number is not known.
   */
  public static int lineNumber(NodeList nodeList)
  {
    if (nodeList == null || nodeList.getLength() == 0)
      return -1;
    
    Node node = nodeList.item(0);
    int nodeHandler = ((DTMNodeProxy)node).getDTMNodeNumber();
    SourceLocator locator = ((DTMNodeProxy)node).getDTM()
      .getSourceLocatorFor(nodeHandler);

    if (locator != null)
      return locator.getLineNumber();
    else
      return -1;
  }

  /**
   * <code>columnNumber</code> returns the column number of the
   * current context node.
   *
   * NOTE: Xalan does not normally record location information for each node. 
   * To obtain it, you must set the custom TrAX attribute 
   * "http://xml.apache.org/xalan/features/source_location"
   * true in the TransformerFactory before generating the Transformer and executing
   * the stylesheet. Storage cost per node will be noticably increased in this mode.
   *
   * @param context an <code>ExpressionContext</code> value
   * @return an <code>int</code> value. This may be -1 to indicate that the
   * column number is not known.
   */
  public static int columnNumber(ExpressionContext context)
  {
    Node contextNode = context.getContextNode();
    int nodeHandler = ((DTMNodeProxy)contextNode).getDTMNodeNumber();
    SourceLocator locator = ((DTMNodeProxy)contextNode).getDTM()
      .getSourceLocatorFor(nodeHandler);

    if (locator != null)
      return locator.getColumnNumber();
    else
      return -1;
  }

  /**
   * <code>columnNumber</code> returns the column number of the node
   * passed as argument. If a node set is passed as argument, the line
   * number of the first node in the set is returned.
   *
   * NOTE: Xalan does not normally record location information for each node. 
   * To obtain it, you must set the custom TrAX attribute 
   * "http://xml.apache.org/xalan/features/source_location"
   * true in the TransformerFactory before generating the Transformer and executing
   * the stylesheet. Storage cost per node will be noticably increased in this mode.
   *
   * @param nodeList a <code>NodeList</code> value
   * @return an <code>int</code> value. This may be -1 to indicate that the
   * column number is not known.
   */
  public static int columnNumber(NodeList nodeList)
  {
    if (nodeList == null || nodeList.getLength() == 0)
      return -1;
    
    Node node = nodeList.item(0);
    int nodeHandler = ((DTMNodeProxy)node).getDTMNodeNumber();
    SourceLocator locator = ((DTMNodeProxy)node).getDTM()
      .getSourceLocatorFor(nodeHandler);

    if (locator != null)
      return locator.getColumnNumber();
    else
      return -1;
  }
}