Hash.java Source code

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Here is the source code for Hash.java

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/*
 * 
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999-2003 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. 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.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:  
 *       "This product includes software developed by the 
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Jakarta Element Construction Set", 
 *    "Jakarta ECS" , and "Apache Software Foundation" must not be used 
 *    to endorse or promote products derived
 *    from this software without prior written permission. For written 
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Jakarta Element Construction Set" nor "Jakarta ECS" nor may "Apache" 
 *    appear in their names without prior written permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 THE APACHE SOFTWARE FOUNDATION OR
 * ITS 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.
    
 *
 */

import java.util.Enumeration;

public class Hash implements java.io.Serializable {
    private Array keys = new Array();

    private Array elements = new Array();

    public Hash() {
    }

    public void setSize(int newSize) {
        keys.setSize(newSize);
        elements.setSize(newSize);
    }

    public void setGrow(int growBy) {
        keys.setGrow(growBy);
        elements.setGrow(growBy);
    }

    public synchronized void put(String key, Object element) {
        try {
            if (containsKey(key)) {
                elements.add(keys.location(key), element);
            } else {
                keys.add(key);
                elements.add(element);
            }
        } catch (NoSuchObjectException nsoe) {
        }
    }

    public synchronized void remove(String key) {
        try {
            if (containsKey(key)) {
                elements.remove(keys.location(key));
                elements.remove(elements.location(key));
            }
        } catch (NoSuchObjectException nsoe) {
        }
    }

    public int size() {
        return keys.getCurrentSize();
    }

    public boolean contains(Object element) {
        try {
            elements.location(element);
            return (true);
        } catch (NoSuchObjectException noSuchObject) {
            return false;
        }
    }

    public Enumeration keys() {
        return keys;
    }

    public boolean containsKey(String key) {
        try {
            keys.location(key);
        } catch (NoSuchObjectException noSuchObject) {
            return false;
        }
        return (true);
    }

    public Enumeration elements() {
        return elements;
    }

    public Object get(String key) {
        try {
            if (containsKey(key))
                return (elements.get(keys.location(key)));
        } catch (NoSuchObjectException nsoe) {
        }
        return null;
    }
}

class Array implements java.util.Enumeration, java.io.Serializable {
    private int current = 0;

    private int size = 10;

    private int grow = 2;

    private int place = 0;

    private Object[] elements = null;

    private Object[] tmpElements = null;

    public Array() {
        init();
    }

    public Array(int size) {
        setSize(size);
        init();
    }

    public Array(int size, int grow) {
        setSize(size);
        setGrow(grow);
        init();
    }

    private void init() {
        elements = new Object[size];
    }

    public Object nextElement() throws java.util.NoSuchElementException {
        if (elements[place] != null && place != current) {
            place++;
            return elements[place - 1];
        } else {
            place = 0;
            throw new java.util.NoSuchElementException();
        }
    }

    public boolean hasMoreElements() {
        if (place < elements.length && current != place)
            return true;
        return false;
    }

    public void setSize(int size) {
        this.size = size;
    }

    public int getCurrentSize() {
        return current;
    }

    public void rehash() {
        tmpElements = new Object[size];
        int count = 0;
        for (int x = 0; x < elements.length; x++) {
            if (elements[x] != null) {
                tmpElements[count] = elements[x];
                count++;
            }
        }
        elements = (Object[]) tmpElements.clone();
        tmpElements = null;
        current = count;
    }

    public void setGrow(int grow) {
        this.grow = grow;
    }

    public void grow() {
        size = size += (size / grow);
        rehash();
    }

    public void add(Object o) {
        if (current == elements.length)
            grow();

        try {
            elements[current] = o;
            current++;
        } catch (java.lang.ArrayStoreException ase) {
        }
    }

    public void add(int location, Object o) {
        try {
            elements[location] = o;
        } catch (java.lang.ArrayStoreException ase) {
        }
    }

    public void remove(int location) {
        elements[location] = null;
    }

    public int location(Object o) throws NoSuchObjectException {
        int loc = -1;
        for (int x = 0; x < elements.length; x++) {
            if ((elements[x] != null && elements[x] == o) || (elements[x] != null && elements[x].equals(o))) {
                loc = x;
                break;
            }
        }
        if (loc == -1)
            throw new NoSuchObjectException();
        return (loc);
    }

    public Object get(int location) {
        return elements[location];
    }

    public java.util.Enumeration elements() {
        return this;
    }
}

class NoSuchObjectException extends Exception {

    public NoSuchObjectException() {
        super("No such object found.");
    }
}