tintdoublehashmap.java~3~

垃圾邮件过滤器源代码

///////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2001, Eric D. Friedman All Rights Reserved.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
///////////////////////////////////////////////////////////////////////////////

package gnu.trove;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

/**
 * An open addressed Map implementation for int keys and double values.
 *
 *整数与双精度浮点数之间映射的实现?????
 * Created: Sun Nov  4 08:52:45 2001
 *
 * @author Eric D. Friedman
 * @version $Id: TIntDoubleHashMap.java,v 1.17 2005/03/26 17:52:56 ericdf Exp $
 */
public class TIntDoubleHashMap extends TIntHash implements Serializable {

    /** compatible serialization ID - not present in 1.1b3 and earlier */
    static final long serialVersionUID = 1L;

    /** the values of the map */
    // 映射值
    protected transient double[] _values;

    /**
     * Creates a new <code>TIntDoubleHashMap</code> instance with the default
     * capacity and load factor.
     */
    public TIntDoubleHashMap() {
        super();
    }

    /**
     * Creates a new <code>TIntDoubleHashMap</code> instance with a prime
     * capacity equal to or greater than <tt>initialCapacity</tt> and
     * with the default load factor.
     *
     * @param initialCapacity an <code>int</code> value
     */
    public TIntDoubleHashMap(int initialCapacity) {
        super(initialCapacity);
    }

    /**
     * Creates a new <code>TIntDoubleHashMap</code> instance with a prime
     * capacity equal to or greater than <tt>initialCapacity</tt> and
     * with the specified load factor.
     *
     * @param initialCapacity an <code>int</code> value
     * @param loadFactor a <code>float</code> value
     */
    public TIntDoubleHashMap(int initialCapacity, float loadFactor) {
        super(initialCapacity, loadFactor);
    }

    /**
     * Creates a new <code>TIntDoubleHashMap</code> instance with the default
     * capacity and load factor.
     * @param strategy used to compute hash codes and to compare keys.
     */
    public TIntDoubleHashMap(TIntHashingStrategy strategy) {
        super(strategy);
    }

    /**
     * Creates a new <code>TIntDoubleHashMap</code> instance whose capacity
     * is the next highest prime above <tt>initialCapacity + 1</tt>
     * unless that value is already prime.
     *
     * @param initialCapacity an <code>int</code> value
     * @param strategy used to compute hash codes and to compare keys.
     */
    public TIntDoubleHashMap(int initialCapacity, TIntHashingStrategy strategy) {
        super(initialCapacity, strategy);
    }

    /**
     * Creates a new <code>TIntDoubleHashMap</code> instance with a prime
     * value at or near the specified capacity and load factor.
     *
     * @param initialCapacity used to find a prime capacity for the table.
     * @param loadFactor used to calculate the threshold over which
     * rehashing takes place.
     * @param strategy used to compute hash codes and to compare keys.
     */
    public TIntDoubleHashMap(int initialCapacity, float loadFactor, TIntHashingStrategy strategy) {
        super(initialCapacity, loadFactor, strategy);
    }

    /**
     * @return a deep clone of this collection
     */
    public Object clone() {
      TIntDoubleHashMap m = (TIntDoubleHashMap)super.clone();
      m._values = (double[])this._values.clone();
      return m;
    }

    /**
     * @return a TIntDoubleIterator with access to this map's keys and values
     */
    public TIntDoubleIterator iterator() {
        return new TIntDoubleIterator(this);
    }

    /**
     * initializes the hashtable to a prime capacity which is at least
     * <tt>initialCapacity + 1</tt>.
     *
     * @param initialCapacity an <code>int</code> value
     * @return the actual capacity chosen
     */
    protected int setUp(int initialCapacity) {
        int capacity;

        capacity = super.setUp(initialCapacity);
        _values = new double[capacity];
        return capacity;
    }

    /**
     * Inserts a key/value pair into the map.
     * 向HASH映射中插入一个键/值对
     * @param key an <code>int</code> value
     * @param value an <code>double</code> value
     * @return the previous value associated with <tt>key</tt>,
     * or (double)0 if none was found.
     */
    public double put(int key, double value) {
        byte previousState;
        double previous = (double)0;
        int index = insertionIndex(key);
        boolean isNewMapping = true;
        if (index < 0) {
            index = -index -1;
            previous = _values[index];
            isNewMapping = false;
        }
        previousState = _states[index];
        _set[index] = key;
        _states[index] = FULL;
        _values[index] = value;
        if (isNewMapping) {
            postInsertHook(previousState == FREE);
        }

        return previous;
    }

    /**
     * rehashes the map to the new capacity.
     *
     * @param newCapacity an <code>int</code> value
     */
    protected void rehash(int newCapacity) {
        int oldCapacity = _set.length;
        int oldKeys[] = _set;
        double oldVals[] = _values;
        byte oldStates[] = _states;

        _set = new int[newCapacity];
        _values = new double[newCapacity];
        _states = new byte[newCapacity];

        for (int i = oldCapacity; i-- > 0;) {
            if(oldStates[i] == FULL) {
                int o = oldKeys[i];
                int index = insertionIndex(o);
                _set[index] = o;
                _values[index] = oldVals[i];
                _states[index] = FULL;
            }
        }
    }

    /**
     * retrieves the value for <tt>key</tt>
     * 根据键,检索值
     * @param key an <code>int</code> value
     * @return the value of <tt>key</tt> or (double)0 if no such mapping exists.
     */
    public double get(int key) {
        int index = index(key);
        return index < 0 ? (double)0 : _values[index];
    }

    /**
     * Empties the map.
     *
     */
    public void clear() {
        super.clear();
        int[] keys = _set;
        double[] vals = _values;
        byte[] states = _states;

        for (int i = keys.length; i-- > 0;) {
            keys[i] = (int)0;
            vals[i] = (double)0;
            states[i] = FREE;
        }
    }

    /**
     * Deletes a key/value pair from the map.
     *
     * @param key an <code>int</code> value
     * @return an <code>double</code> value, or (double)0 if no mapping for key exists
     */
    public double remove(int key) {
        double prev = (double)0;
        int index = index(key);
        if (index >= 0) {
            prev = _values[index];
            removeAt(index);    // clear key,state; adjust size
        }
        return prev;
    }

    /**
     * Compares this map with another map for equality of their stored
     * entries.
     *
     * @param other an <code>Object</code> value
     * @return a <code>boolean</code> value
     */
    public boolean equals(Object other) {
        if (! (other instanceof TIntDoubleHashMap)) {
            return false;
        }
        TIntDoubleHashMap that = (TIntDoubleHashMap)other;
        if (that.size() != this.size()) {
            return false;
        }
        return forEachEntry(new EqProcedure(that));
    }

    public int hashCode() {