code: /*
   * 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 org.apache.xalan.extensions.ExpressionContext;
  import org.apache.xml.dtm.DTMIterator;
  import org.apache.xml.dtm.ref.DTMNodeIterator;
  import org.apache.xpath.NodeSet;
  
  /**
   * This class contains EXSLT common extension functions.
   * It is accessed by specifying a namespace URI as follows:
   * <pre>
   *    xmlns:exslt="http://exslt.org/common"
   * </pre>
   * 
   * The documentation for each function has been copied from the relevant
   * EXSLT Implementer page.
   * 
   * @see <a href="http://www.exslt.org/">EXSLT</a>
   * @xsl.usage general
   */
  public class ExsltCommon
  {
    /**
     * The exsl:object-type function returns a string giving the type of the object passed 
     * as the argument. The possible object types are: 'string', 'number', 'boolean', 
     * 'node-set', 'RTF', or 'external'. 
     * 
     * Most XSLT object types can be coerced to each other without error. However, there are 
     * certain coercions that raise errors, most importantly treating anything other than a 
     * node set as a node set. Authors of utilities such as named templates or user-defined 
     * extension functions may wish to give some flexibility in the parameter and argument values 
     * that are accepted by the utility; the exsl:object-type function enables them to do so.
     * 
     * The Xalan extensions MethodResolver converts 'object-type' to 'objectType'.
     * 
     * @param obj The object to be typed.
     * @return objectType 'string', 'number', 'boolean', 'node-set', 'RTF', or 'external'.
     * 
     * @see <a href="http://www.exslt.org/">EXSLT</a>
     */
    public static String objectType (Object obj)
    {
      if (obj instanceof String)
        return "string";
      else if (obj instanceof Boolean)
        return "boolean";
      else if (obj instanceof Number)
        return "number";
      else if (obj instanceof DTMNodeIterator)
      {
        DTMIterator dtmI = ((DTMNodeIterator)obj).getDTMIterator();
        if (dtmI instanceof org.apache.xpath.axes.RTFIterator)
        	return "RTF";
        else
          return "node-set";
      }
      else
        return "unknown";
    }
      
    /**
     * The exsl:node-set function converts a result tree fragment (which is what you get 
     * when you use the content of xsl:variable rather than its select attribute to give 
     * a variable value) into a node set. This enables you to process the XML that you create 
     * within a variable, and therefore do multi-step processing. 
     * 
     * You can also use this function to turn a string into a text node, which is helpful 
     * if you want to pass a string to a function that only accepts a node set.
     * 
     * The Xalan extensions MethodResolver converts 'node-set' to 'nodeSet'.
     * 
     * @param myProcessor is passed in by the Xalan extension processor
     * @param rtf The result tree fragment to be converted to a node-set.
     * 
     * @return node-set with the contents of the result tree fragment.
     * 
     * Note: Already implemented in the xalan namespace as nodeset.
     * 
     * @see <a href="http://www.exslt.org/">EXSLT</a>
     */
    public static NodeSet nodeSet(ExpressionContext myProcessor, Object rtf)
    {
      return Extensions.nodeset(myProcessor, rtf);
    }
   
  }
  