/*
    * 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 org.apache.commons.el;
  
  import java.util.List;
  
  import javax.servlet.jsp.el.ELException;
  import javax.servlet.jsp.el.FunctionMapper;
  import javax.servlet.jsp.el.VariableResolver;
  
  /**
   *
   * <p>An expression representing one or more unary operators on a
   * value
   * 
   * @author Nathan Abramson - Art Technology Group
   * @author Shawn Bayern
   * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: bayard $
   **/
  
  public class UnaryOperatorExpression
    extends Expression
  {
    //-------------------------------------
    // Properties
    //-------------------------------------
    // property operator
  
    UnaryOperator mOperator;
    public UnaryOperator getOperator ()
    { return mOperator; }
    public void setOperator (UnaryOperator pOperator)
    { mOperator = pOperator; }
  
    //-------------------------------------
    // property operators
  
    List mOperators;
    public List getOperators ()
    { return mOperators; }
    public void setOperators (List pOperators)
    { mOperators = pOperators; }
  
    //-------------------------------------
    // property expression
  
    Expression mExpression;
    public Expression getExpression ()
    { return mExpression; }
    public void setExpression (Expression pExpression)
    { mExpression = pExpression; }
  
    //-------------------------------------
    /**
     *
     * Constructor
     **/
    public UnaryOperatorExpression (UnaryOperator pOperator,
  				  List pOperators,
  				  Expression pExpression)
    {
      mOperator = pOperator;
      mOperators = pOperators;
      mExpression = pExpression;
    }
  
    //-------------------------------------
    // Expression methods
    //-------------------------------------
    /**
     *
     * Returns the expression in the expression language syntax
     **/
    public String getExpressionString ()
    {
      StringBuffer buf = new StringBuffer ();
      buf.append ("(");
      if (mOperator != null) {
        buf.append (mOperator.getOperatorSymbol ());
        buf.append (" ");
      }
      else {
        for (int i = 0, size = mOperators.size(); i < size; i++) {
  	UnaryOperator operator = (UnaryOperator) mOperators.get (i);
  	buf.append (operator.getOperatorSymbol ());
 	buf.append (" ");
       }
     }
     buf.append (mExpression.getExpressionString ());
     buf.append (")");
     return buf.toString ();
   }
 
   //-------------------------------------
   /**
    *
    * Evaluates to the literal value
    **/
   public Object evaluate (VariableResolver pResolver, FunctionMapper functions)
     throws ELException
   {
     Object value = mExpression.evaluate (pResolver, functions);
     if (mOperator != null) {
       value = mOperator.apply (value);
     }
     else {
       for (int i = mOperators.size () - 1; i >= 0; i--) {
 	UnaryOperator operator = (UnaryOperator) mOperators.get (i);
 	value = operator.apply (value);
       }
     }
     return value;
   }
 
   public Expression bindFunctions(final FunctionMapper functions) throws ELException {
       return new UnaryOperatorExpression(
               mOperator,
               mOperators,
               mExpression.bindFunctions(functions));
   }
 
   //-------------------------------------
 }