/*
 * The Apache Software License, Version 1.1
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 * Copyright (c) 1999 The Apache Software Foundation.  All rights 
 * reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
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 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
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 *    notice, this list of conditions and the following disclaimer in
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 *    distribution.
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 *    any, must include the following acknowlegement:  
 *       "This product includes software developed by the 
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
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package org.apache.commons.el;

import javax.servlet.jsp.el.ELException;

/**
 *
 * <p>The implementation of the and operator
 * 
 * @author Nathan Abramson - Art Technology Group
 * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: luehe $
 **/

public class AndOperator
  extends BinaryOperator
{
  //-------------------------------------
  // Singleton
  //-------------------------------------

  public static final AndOperator SINGLETON =
    new AndOperator ();

  //-------------------------------------
  /**
   *
   * Constructor
   **/
  public AndOperator ()
  {
  }

  //-------------------------------------
  // Expression methods
  //-------------------------------------
  /**
   *
   * Returns the symbol representing the operator
   **/
  public String getOperatorSymbol ()
  {
    return "and";
  }

  //-------------------------------------
  /**
   *
   * Applies the operator to the given value
   **/
  public Object apply (Object pLeft,
		       Object pRight,
		       Logger pLogger)
    throws ELException
  {
    // Coerce the values to booleans
    boolean left = 
      Coercions.coerceToBoolean (pLeft, pLogger).booleanValue ();
    boolean right = 
      Coercions.coerceToBoolean (pRight, pLogger).booleanValue ();

    return PrimitiveObjects.getBoolean (left && right);
  }

  //-------------------------------------
  /**
   *
   * Returns true if evaluation is necessary given the specified Left
   * value.  The And/OrOperators make use of this
   **/
  public boolean shouldEvaluate (Object pLeft)
  {
    return
      (pLeft instanceof Boolean) &&
      ((Boolean) pLeft).booleanValue () == true;
  }

  //-------------------------------------
  /**
   *
   * Returns true if the operator expects its arguments to be coerced
   * to Booleans.  The And/Or operators set this to true.
   **/
  public boolean shouldCoerceToBoolean ()
  {
    return true;
  }

  //-------------------------------------
}