/*

 * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.

 */

/*

 * 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.

 */

/*

 * $Id: CustomStringPool.java,v 1.2.4.1 2005/09/15 08:14:59 suresh_emailid Exp $

 */

package com.sun.org.apache.xml.internal.dtm.ref;

import java.util.HashMap;

import java.util.Map;

/**

 * CustomStringPool is an example of an application-provided data structure for a

 * DTM implementation to hold symbol references, e.g. element names. It will

 * follow the DTMStringPool interface and use two simple methods

 * indexToString(int i) and stringToIndex(String s) to map between a set of

 * string values and a set of integer index values. Therefore, an application

 * may improve DTM processing speed by substituting the DTM symbol resolution

 * tables with application specific quick symbol resolution tables.

 * <p>

 * %REVIEW% The only difference between this an DTMStringPool seems to be that

 * it uses a java.lang.Hashtable full of Integers rather than implementing its

 * own hashing. Joe deliberately avoided that approach when writing

 * DTMStringPool, since it is both much more memory-hungry and probably slower

 * -- especially in JDK 1.1.x, where Hashtable is synchronized. We need to

 * either justify this implementation or discard it.

 *

 * <p>

 * Status: In progress, under discussion.

 *

 * @LastModified: Oct 2017

 */

public class CustomStringPool extends DTMStringPool {

    final Map<String, Integer> m_stringToInt = new HashMap<>();

    public static final int NULL = -1;

    public CustomStringPool() {

        super();

    }

    public void removeAllElements() {

        m_intToString.clear();

        if (m_stringToInt != null) {

            m_stringToInt.clear();

        }

    }

    /**

     * @return string whose value is uniquely identified by this integer index.

     * @throws java.lang.IndexOutOfBoundsException if index doesn't map to

     * a string.

     */

    @Override

    public String indexToString(int i)

            throws IndexOutOfBoundsException {

        return m_intToString.get(i);

    }

    /**

     * @return integer index uniquely identifying the value of this string.

     */

    @Override

    public int stringToIndex(String s) {

        if (s == null) {

            return NULL;

        }

        Integer iobj = m_stringToInt.get(s);

        if (iobj == null) {

            m_intToString.add(s);

            iobj = m_intToString.size();

            m_stringToInt.put(s, iobj);

        }

        return iobj;

    }

}