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Java example source code file (IntegerArray.java)

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

Learn more about this Java project at its project page.

Java - Java tags/keywords

initialsize, integerarray, object

The IntegerArray.java Java example source code

/*
 * reserved comment block
 * DO NOT REMOVE OR ALTER!
 */
/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * 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.
 */
/*
 * $Id: IntegerArray.java,v 1.2.4.1 2005/09/06 11:44:56 pvedula Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.util;

/**
 * @author Jacek Ambroziak
 */
public final class IntegerArray {
    private static final int InitialSize = 32;

    private int[] _array;
    private int   _size;
    private int   _free = 0;

    public IntegerArray() {
        this(InitialSize);
    }

    public IntegerArray(int size) {
        _array = new int[_size = size];
    }

    public IntegerArray(int[] array) {
        this(array.length);
        System.arraycopy(array, 0, _array, 0, _free = _size);
    }

    public void clear() {
        _free = 0;
    }

    public Object clone() {
        final IntegerArray clone = new IntegerArray(_free > 0 ? _free : 1);
        System.arraycopy(_array, 0, clone._array, 0, _free);
        clone._free = _free;
        return clone;
    }

    public int[] toIntArray() {
        final int[] result = new int[cardinality()];
        System.arraycopy(_array, 0, result, 0, cardinality());
        return result;
    }

    public final int at(int index) {
        return _array[index];
    }

    public final void set(int index, int value) {
        _array[index] = value;
    }

    public int indexOf(int n) {
        for (int i = 0; i < _free; i++) {
            if (n == _array[i]) return i;
        }
        return -1;
    }

    public final void add(int value) {
        if (_free == _size) {
            growArray(_size * 2);
        }
        _array[_free++] = value;
    }

    /**
     * Adds new int at the end if not already present.
     */
    public void addNew(int value) {
        for (int i = 0; i < _free; i++) {
            if (_array[i] == value) return;  // already in array
        }
        add(value);
    }

    public void reverse() {
        int left = 0;
        int right = _free - 1;

        while (left < right) {
            int temp = _array[left];
            _array[left++] = _array[right];
            _array[right--] = temp;
        }
    }

    /**
     * Merge two sorted arrays and eliminate duplicates.
     * Elements of the other IntegerArray must not be changed.
     */
    public void merge(final IntegerArray other) {
        final int newSize = _free + other._free;
// System.out.println("IntegerArray.merge() begin newSize = " + newSize);
        int[] newArray = new int[newSize];

        // Merge the two arrays
        int i = 0, j = 0, k;
        for (k = 0; i < _free && j < other._free; k++) {
            int x = _array[i];
            int y = other._array[j];

            if (x < y) {
                newArray[k] = x;
                i++;
            }
            else if (x > y) {
                newArray[k] = y;
                j++;
            }
            else {
                newArray[k] = x;
                i++; j++;
            }
        }

        // Copy the rest if of different lengths
        if (i >= _free) {
            while (j < other._free) {
                newArray[k++] = other._array[j++];
            }
        }
        else {
            while (i < _free) {
                newArray[k++] = _array[i++];
            }
        }

        // Update reference to this array
        _array = newArray;
        _free = _size = newSize;
// System.out.println("IntegerArray.merge() end");
    }

    public void sort() {
        quicksort(_array, 0, _free - 1);
    }

    private static void quicksort(int[] array, int p, int r) {
        if (p < r) {
            final int q = partition(array, p, r);
            quicksort(array, p, q);
            quicksort(array, q + 1, r);
        }
    }

    private static int partition(int[] array, int p, int r) {
        final int x = array[(p + r) >>> 1];
        int i = p - 1; int j = r + 1;

        while (true) {
            while (x < array[--j]);
            while (x > array[++i]);
            if (i < j) {
                int temp = array[i];
                array[i] = array[j];
                array[j] = temp;
            }
            else {
                return j;
            }
        }
    }

    private void growArray(int size) {
        final int[] newArray = new int[_size = size];
        System.arraycopy(_array, 0, newArray, 0, _free);
        _array = newArray;
    }

    public int popLast() {
        return _array[--_free];
    }

    public int last() {
        return _array[_free - 1];
    }

    public void setLast(int n) {
        _array[_free - 1] = n;
    }

    public void pop() {
        _free--;
    }

    public void pop(int n) {
        _free -= n;
    }

    public final int cardinality() {
        return _free;
    }

    public void print(java.io.PrintStream out) {
        if (_free > 0) {
            for (int i = 0; i < _free - 1; i++) {
                out.print(_array[i]);
                out.print(' ');
            }
            out.println(_array[_free - 1]);
        }
        else {
            out.println("IntegerArray: empty");
        }
    }
}

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