/*

  * #%L

  * SeenString.java - mongodb-async-driver - Allanbank Consulting, Inc.

  * %%

  * Copyright (C) 2011 - 2014 Allanbank Consulting, Inc.

  * %%

  * 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.

  * #L%

  */

 package com.allanbank.mongodb.bson.io;

 import java.util.Arrays;

 import java.util.concurrent.atomic.AtomicInteger;

 import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;

 /**

  * SeenString is a record of the byte[], value and count for each string/byte[]

  * the cache sees.

  * 

  * @api.no This class is <b>NOT</b> part of the drivers API. This class may be

  *         mutated in incompatible ways between any two releases of the driver.

  * @copyright 2014, Allanbank Consulting, Inc., All Rights Reserved

  */

 class SeenString {

     /**

      * Atomic updated for all of the SeenString instances to cut down on the

      * number of {@link AtomicInteger} entries required.

      */

     private final static AtomicIntegerFieldUpdater<SeenString> ourCountUpdater = AtomicIntegerFieldUpdater

             .newUpdater(SeenString.class, "myCount");

     /** The encoded bytes for the seen string. */

     private final byte[] myBytes;

     /** The number of times the string is seen. */

     private volatile int myCount;

     /** The value for the seen string. */

     private final String myValue;

     /**

      * Creates a new SeenString.

      * 

      * @param source

      *            The source of the bytes in the string.

      * @param offset

      *            The offset of the first byte to decode.

      * @param length

      *            The length of the bytes to decode with a terminal zero byte.

      * @param decoded

      *            The value for the seen string.

      */

     public SeenString(final byte[] source, final int offset, final int length,

             final String decoded) {

         myBytes = Arrays.copyOfRange(source, offset, offset + length);

         myValue = decoded;

         myCount = 0;

     }

     /**

      * Returns the encoded bytes for the seen string.

      * 

      * @return The encoded bytes for the seen string.

      */

     public byte[] getBytes() {

         return myBytes;

     }

     /**

      * Returns the number of times the string is seen.

      * 

      * @return The number of times the string is seen.

      */

     public int getCount() {

         return myCount;

     }

     /**

      * Returns the decoded string for the seen string.

      * 

      * @return The decoded string for the seen string.

      */

     public String getValue() {

         return myValue;

     }

     /**

      * Increments the number of times that the string has been seen.

      */

     public void incrementCount() {

         ourCountUpdater.incrementAndGet(this);

     }

     /**

      * Sets the count to zero.

      * 

      * @return the previous value for the count.

      */

     public int reset() {

         return ourCountUpdater.getAndSet(this, 0);

     }

 }