/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * 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.

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package com.sun.org.apache.xpath.internal.functions;

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

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

import com.sun.org.apache.xpath.internal.objects.XBoolean;

import com.sun.org.apache.xpath.internal.objects.XObject;

/**

 * Execute the Lang() function.

 * @xsl.usage advanced

 */

public class FuncLang extends FunctionOneArg

{

    static final long serialVersionUID = -7868705139354872185L;

  /**

   * Execute the function.  The function must return

   * a valid object.

   * @param xctxt The current execution context.

   * @return A valid XObject.

   *

   * @throws javax.xml.transform.TransformerException

   */

  public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException

  {

    String lang = m_arg0.execute(xctxt).str();

    int parent = xctxt.getCurrentNode();

    boolean isLang = false;

    DTM dtm = xctxt.getDTM(parent);

    while (DTM.NULL != parent)

    {

      if (DTM.ELEMENT_NODE == dtm.getNodeType(parent))

      {

        int langAttr = dtm.getAttributeNode(parent, "http://www.w3.org/XML/1998/namespace", "lang");

        if (DTM.NULL != langAttr)

        {

          String langVal = dtm.getNodeValue(langAttr);

          // %OPT%

          if (langVal.toLowerCase().startsWith(lang.toLowerCase()))

          {

            int valLen = lang.length();

            if ((langVal.length() == valLen)

                    || (langVal.charAt(valLen) == '-'))

            {

              isLang = true;

            }

          }

          break;

        }

      }

      parent = dtm.getParent(parent);

    }

    return isLang ? XBoolean.S_TRUE : XBoolean.S_FALSE;

  }

}