/*

 * 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: ExsltCommon.java,v 1.2.4.1 2005/09/15 02:45:24 jeffsuttor Exp $

 */

package com.sun.org.apache.xalan.internal.lib;

import com.sun.org.apache.xalan.internal.extensions.ExpressionContext;

import com.sun.org.apache.xml.internal.dtm.DTMIterator;

import com.sun.org.apache.xml.internal.dtm.ref.DTMNodeIterator;

import com.sun.org.apache.xpath.internal.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 com.sun.org.apache.xpath.internal.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);

  }

}