ComplexKeyHashMap.java Source code

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Here is the source code for ComplexKeyHashMap.java

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/*
 * Copyright 2003-2007 the original author or authors.
 *
 * 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.
 */

import java.util.NoSuchElementException;

public class ComplexKeyHashMap {
    public static class Entry {
        public int hash;
        public Entry next;
        public Object value;

        public Object getValue() {
            return value;
        }

        public void setValue(Object value) {
            this.value = value;
        }
    }

    protected Entry table[];

    protected static final int DEFAULT_CAPACITY = 32;
    protected static final int MINIMUM_CAPACITY = 4;
    protected static final int MAXIMUM_CAPACITY = 1 << 28;

    protected int size;
    protected transient int threshold;

    public ComplexKeyHashMap() {
        init(DEFAULT_CAPACITY);
    }

    public ComplexKeyHashMap(boolean b) {
    }

    public ComplexKeyHashMap(int expectedMaxSize) {
        init(capacity(expectedMaxSize));
    }

    public static int hash(int h) {
        h += ~(h << 9);
        h ^= (h >>> 14);
        h += (h << 4);
        h ^= (h >>> 10);
        return h;
    }

    public int size() {
        return size;
    }

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

    public void clear() {
        Object[] tab = table;
        for (int i = 0; i < tab.length; i++)
            tab[i] = null;
        size = 0;
    }

    public void init(int initCapacity) {
        threshold = (initCapacity * 6) / 8;
        table = new Entry[initCapacity];
    }

    public void resize(int newLength) {
        Entry[] oldTable = table;
        int oldLength = table.length;

        Entry[] newTable = new Entry[newLength];

        for (int j = 0; j < oldLength; j++) {

            for (Entry e = oldTable[j]; e != null;) {
                Entry next = e.next;
                int index = e.hash & (newLength - 1);

                e.next = newTable[index];
                newTable[index] = e;

                e = next;
            }
        }

        table = newTable;
        threshold = (6 * newLength) / 8;
    }

    private int capacity(int expectedMaxSize) {
        // Compute min capacity for expectedMaxSize given a load factor of 3/4
        int minCapacity = (8 * expectedMaxSize) / 6;

        // Compute the appropriate capacity
        int result;
        if (minCapacity > MAXIMUM_CAPACITY || minCapacity < 0) {
            result = MAXIMUM_CAPACITY;
        } else {
            result = MINIMUM_CAPACITY;
            while (result < minCapacity)
                result <<= 1;
        }
        return result;
    }

    public interface EntryIterator {
        boolean hasNext();

        Entry next();
    }

    public ComplexKeyHashMap.Entry[] getTable() {
        return table;
    }

    public EntryIterator getEntrySetIterator() {
        return new EntryIterator() {
            Entry next; // next entry to return
            int index; // current slot
            Entry current; // current entry

            {
                Entry[] t = table;
                int i = t.length;
                Entry n = null;
                if (size != 0) { // advance to first entry
                    while (i > 0 && (n = t[--i]) == null) {
                    }
                }
                next = n;
                index = i;
            }

            public boolean hasNext() {
                return next != null;
            }

            public Entry next() {
                return nextEntry();
            }

            Entry nextEntry() {
                Entry e = next;
                if (e == null)
                    throw new NoSuchElementException();

                Entry n = e.next;
                Entry[] t = table;
                int i = index;
                while (n == null && i > 0)
                    n = t[--i];
                index = i;
                next = n;
                return current = e;
            }
        };
    }
}