/*

 */

/*

 * 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.xpath.internal.Expression;

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

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

/**

 * Base class for functions that accept two arguments.

 * @xsl.usage advanced

 */

public class Function2Args extends FunctionOneArg

{

    static final long serialVersionUID = 5574294996842710641L;

  /** The second argument passed to the function (at index 1).

   *  @serial  */

  Expression m_arg1;

  /**

   * Return the second argument passed to the function (at index 1).

   *

   * @return An expression that represents the second argument passed to the

   *         function.

   */

  public Expression getArg1()

  {

    return m_arg1;

  }

  /**

   * This function is used to fixup variables from QNames to stack frame

   * indexes at stylesheet build time.

   * @param vars List of QNames that correspond to variables.  This list

   * should be searched backwards for the first qualified name that

   * corresponds to the variable reference qname.  The position of the

   * QName in the vector from the start of the vector will be its position

   * in the stack frame (but variables above the globalsTop value will need

   * to be offset to the current stack frame).

   */

  {

    super.fixupVariables(vars, globalsSize);

    if(null != m_arg1)

      m_arg1.fixupVariables(vars, globalsSize);

  }

  /**

   * Set an argument expression for a function.  This method is called by the

   * XPath compiler.

   *

   * @param arg non-null expression that represents the argument.

   * @param argNum The argument number index.

   *

   * @throws WrongNumberArgsException If the argNum parameter is greater than 1.

   */

  public void setArg(Expression arg, int argNum)

          throws WrongNumberArgsException

  {

    // System.out.println("argNum: "+argNum);

    if (argNum == 0)

      super.setArg(arg, argNum);

    else if (1 == argNum)

    {

      m_arg1 = arg;

      arg.exprSetParent(this);

    }

    else

                  reportWrongNumberArgs();

  }

  /**

   * 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

   */

  public void checkNumberArgs(int argNum) throws WrongNumberArgsException

  {

    if (argNum != 2)

      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("two", null));

  }

  /**

   * 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 super.canTraverseOutsideSubtree()

    ? true : m_arg1.canTraverseOutsideSubtree();

   }

  class Arg1Owner implements ExpressionOwner

  {

    /**

     * @see ExpressionOwner#getExpression()

     */

    public Expression getExpression()

    {

      return m_arg1;

    }

    /**

     * @see ExpressionOwner#setExpression(Expression)

     */

    public void setExpression(Expression exp)

    {

        exp.exprSetParent(Function2Args.this);

        m_arg1 = exp;

    }

  }

  /**

   * @see com.sun.org.apache.xpath.internal.XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor)

   */

  public void callArgVisitors(XPathVisitor visitor)

  {

        super.callArgVisitors(visitor);

        if(null != m_arg1)

                m_arg1.callVisitors(new Arg1Owner(), visitor);

  }

  /**

   * @see Expression#deepEquals(Expression)

   */

  public boolean deepEquals(Expression expr)

  {

        if(!super.deepEquals(expr))

                return false;

        if(null != m_arg1)

        {

                if(null == ((Function2Args)expr).m_arg1)

                        return false;

                if(!m_arg1.deepEquals(((Function2Args)expr).m_arg1))

                        return false;

        }

        else if(null != ((Function2Args)expr).m_arg1)

                return false;

        return true;

  }

}