HSQLDB example source code file (HashMap.java)

This example HSQLDB source code file (HashMap.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - HSQLDB tags/keywords

basehashiterator, collection, collection, hashmap, hashmap, illegalargumentexception, iterator, keyset, object, object, runtimeexception, runtimeexception, set, values

The HSQLDB HashMap.java source code

/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


package org.hsqldb.lib;

import org.hsqldb.store.BaseHashMap;

/**
 * This class does not store null keys.
 *
 * @author fredt@users
 * @version 1.7.2
 * @since 1.7.2
 */
public class HashMap extends BaseHashMap {

    Set        keySet;
    Collection values;

    public HashMap() {
        this(16, 0.75f);
    }

    public HashMap(int initialCapacity) throws IllegalArgumentException {
        this(initialCapacity, 0.75f);
    }

    public HashMap(int initialCapacity,
                   float loadFactor) throws IllegalArgumentException {
        super(initialCapacity, loadFactor, BaseHashMap.objectKeyOrValue,
              BaseHashMap.objectKeyOrValue, false);
    }

    public Object get(Object key) {

        int hash   = key.hashCode();
        int lookup = getLookup(key, hash);

        if (lookup != -1) {
            return objectValueTable[lookup];
        }

        return null;
    }

    public Object put(Object key, Object value) {
        return super.addOrRemove(0, 0, key, value, false);
    }

    public Object remove(Object key) {
        return super.removeObject(key);
    }

    public boolean containsKey(Object key) {
        return super.containsKey(key);
    }

    public boolean containsValue(Object value) {
        return super.containsValue(value);
    }

    public void putAll(HashMap t) {

        Iterator it = t.keySet.iterator();

        while (it.hasNext()) {
            Object key = it.next();

            put(key, t.get(key));
        }
    }

    public Set keySet() {

        if (keySet == null) {
            keySet = new KeySet();
        }

        return keySet;
    }

    public Collection values() {

        if (values == null) {
            values = new Values();
        }

        return values;
    }

    class KeySet implements Set {

        public Iterator iterator() {
            return HashMap.this.new BaseHashIterator(true);
        }

        public int size() {
            return HashMap.this.size();
        }

        public boolean contains(Object o) {
            return containsKey(o);
        }

        public Object get(Object key) {

            int lookup = HashMap.this.getLookup(key, key.hashCode());

            if (lookup < 0) {
                return null;
            } else {
                return HashMap.this.objectKeyTable[lookup];
            }
        }

        public boolean add(Object value) {
            throw new RuntimeException();
        }

        public boolean addAll(Collection c) {
            throw new RuntimeException();
        }

        public boolean remove(Object o) {

            int oldSize = size();

            HashMap.this.remove(o);

            return size() != oldSize;
        }

        public boolean isEmpty() {
            return size() == 0;
        }

        public void clear() {
            HashMap.this.clear();
        }
    }

    class Values implements Collection {

        public Iterator iterator() {
            return HashMap.this.new BaseHashIterator(false);
        }

        public int size() {
            return HashMap.this.size();
        }

        public boolean contains(Object o) {
            throw new RuntimeException();
        }

        public boolean add(Object value) {
            throw new RuntimeException();
        }

        public boolean addAll(Collection c) {
            throw new RuntimeException();
        }

        public boolean remove(Object o) {
            throw new RuntimeException();
        }

        public boolean isEmpty() {
            return size() == 0;
        }

        public void clear() {
            HashMap.this.clear();
        }
    }
}