// Copyright 2006 The Apache Software Foundation

 //

 // Licensed 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.tapestry5.internal.util;

 import java.util.Arrays;

 /**

  * Combines multiple values to form a single composite key. MultiKey can often be used as an alternative to nested

  * maps.

  */

 public final class MultiKey

 {

     private static final int PRIME = 31;

     private final Object[] values;

     private final int hashCode;

     /**

      * Creates a new instance from the provided values. It is assumed that the values provided are good map keys

      * themselves -- immutable, with proper implementations of equals() and hashCode().

      *

      * @param values

      */

     public MultiKey(Object... values)

     {

         this.values = values;

         hashCode = PRIME * Arrays.hashCode(this.values);

     }

     @Override

     public int hashCode()

     {

         return hashCode;

     }

     @Override

     public boolean equals(Object obj)

     {

         if (this == obj)

             return true;

         if (obj == null)

             return false;

         if (getClass() != obj.getClass())

             return false;

         final MultiKey other = (MultiKey) obj;

         return Arrays.equals(values, other.values);

     }

     @Override

     public String toString()

     {

         StringBuilder builder = new StringBuilder("MultiKey[");

         boolean first = true;

         for (Object o : values)

         {

             if (!first)

                 builder.append(", ");

             builder.append(o);

             first = false;

         }

         builder.append("]");

         return builder.toString();

     }

 }