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 * 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.

 */

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

import com.sun.org.apache.xalan.internal.res.XSLMessages;

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

import com.sun.org.apache.xml.internal.utils.XMLString;

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

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

import com.sun.org.apache.xpath.internal.res.XPATHErrorResources;

/**

 * Base class for functions that accept one argument that can be defaulted if

 * not specified.

 * @xsl.usage advanced

 */

public class FunctionDef1Arg extends FunctionOneArg

{

    static final long serialVersionUID = 2325189412814149264L;

  /**

   * Execute the first argument expression that is expected to return a

   * nodeset.  If the argument is null, then return the current context node.

   *

   * @param xctxt Runtime XPath context.

   *

   * @return The first node of the executed nodeset, or the current context

   *         node if the first argument is null.

   *

   * @throws javax.xml.transform.TransformerException if an error occurs while

   *                                   executing the argument expression.

   */

  protected int getArg0AsNode(XPathContext xctxt)

          throws javax.xml.transform.TransformerException

  {

    return (null == m_arg0)

           ? xctxt.getCurrentNode() : m_arg0.asNode(xctxt);

  }

  /**

   * Tell if the expression is a nodeset expression.

   * @return true if the expression can be represented as a nodeset.

   */

  public boolean Arg0IsNodesetExpr()

  {

    return (null == m_arg0) ? true : m_arg0.isNodesetExpr();

  }

  /**

   * Execute the first argument expression that is expected to return a

   * string.  If the argument is null, then get the string value from the

   * current context node.

   *

   * @param xctxt Runtime XPath context.

   *

   * @return The string value of the first argument, or the string value of the

   *         current context node if the first argument is null.

   *

   * @throws javax.xml.transform.TransformerException if an error occurs while

   *                                   executing the argument expression.

   */

  protected XMLString getArg0AsString(XPathContext xctxt)

          throws javax.xml.transform.TransformerException

  {

    if(null == m_arg0)

    {

      int currentNode = xctxt.getCurrentNode();

      if(DTM.NULL == currentNode)

        return XString.EMPTYSTRING;

      else

      {

        DTM dtm = xctxt.getDTM(currentNode);

        return dtm.getStringValue(currentNode);

      }

    }

    else

      return m_arg0.execute(xctxt).xstr();

  }

  /**

   * Execute the first argument expression that is expected to return a

   * number.  If the argument is null, then get the number value from the

   * current context node.

   *

   * @param xctxt Runtime XPath context.

   *

   * @return The number value of the first argument, or the number value of the

   *         current context node if the first argument is null.

   *

   * @throws javax.xml.transform.TransformerException if an error occurs while

   *                                   executing the argument expression.

   */

  protected double getArg0AsNumber(XPathContext xctxt)

          throws javax.xml.transform.TransformerException

  {

    if(null == m_arg0)

    {

      int currentNode = xctxt.getCurrentNode();

      if(DTM.NULL == currentNode)

        return 0;

      else

      {

        DTM dtm = xctxt.getDTM(currentNode);

        XMLString str = dtm.getStringValue(currentNode);

        return str.toDouble();

      }

    }

    else

      return m_arg0.execute(xctxt).num();

  }

  /**

   * Check that the number of arguments passed to this function is correct.

   *

   * @param argNum The number of arguments that is being passed to the function.

   *

   * @throws WrongNumberArgsException if the number of arguments is not 0 or 1.

   */

  public void checkNumberArgs(int argNum) throws WrongNumberArgsException

  {

    if (argNum > 1)

      reportWrongNumberArgs();

  }

  /**

   * Constructs and throws a WrongNumberArgException with the appropriate

   * message for this function object.

   *

   * @throws WrongNumberArgsException

   */

  protected void reportWrongNumberArgs() throws WrongNumberArgsException {

      throw new WrongNumberArgsException(XSLMessages.createXPATHMessage(XPATHErrorResources.ER_ZERO_OR_ONE, null)); //"0 or 1");

  }

  /**

   * Tell if this expression or it's subexpressions can traverse outside

   * the current subtree.

   *

   * @return true if traversal outside the context node's subtree can occur.

   */

  public boolean canTraverseOutsideSubtree()

  {

    return (null == m_arg0) ? false : super.canTraverseOutsideSubtree();

  }

}