HSQLDB example source code file (HsqlArrayList.java)

This example HSQLDB source code file (HsqlArrayList.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

baselist, default_initial_capacity, default_resize_factor, hsqlarraylist, hsqlarraylist, hsqllist, index, index, indexoutofboundsexception, indexoutofboundsexception, invalid, negativearraysizeexception, object, object, reflection

The HSQLDB HsqlArrayList.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 java.lang.reflect.Array;

// fredt@users - 1.8.0 - enhancements

/**
 * Intended as an asynchronous alternative to Vector.  Use HsqlLinkedList
 * instead if its better suited.
 *
 * @author dnordahl@users
 * @version 1.8.0
 * @since 1.7.0
 */
public class HsqlArrayList extends BaseList implements HsqlList {

//fredt@users
/*
    private static Reporter reporter = new Reporter();

    private static class Reporter {

        private static int initCounter   = 0;
        private static int updateCounter = 0;

        Reporter() {

            try {
                System.runFinalizersOnExit(true);
            } catch (SecurityException e) {}
        }

        protected void finalize() {

            System.out.println("HsqlArrayList init count: " + initCounter);
            System.out.println("HsqlArrayList update count: "
                               + updateCounter);
        }
    }
*/
    private static final int   DEFAULT_INITIAL_CAPACITY = 10;
    private static final float DEFAULT_RESIZE_FACTOR    = 2.0f;
    private Object[]           elementData;
    private boolean            minimizeOnClear;

    /** Creates a new instance of HsqlArrayList */
    public HsqlArrayList() {

//        reporter.initCounter++;
        elementData = new Object[DEFAULT_INITIAL_CAPACITY];
    }

    /**
     * Creates a new instance of HsqlArrayList that minimizes the size when
     * empty
     */
    public HsqlArrayList(boolean minimize) {

//        reporter.initCounter++;
        elementData     = new Object[DEFAULT_INITIAL_CAPACITY];
        minimizeOnClear = minimize;
    }

    /** Creates a new instance with the given initial capacity */
    public HsqlArrayList(int initialCapacity) {

//        reporter.initCounter++;
        if (initialCapacity < 0) {
            throw new NegativeArraySizeException(
                "Invalid initial capacity given");
        }

        if (initialCapacity == 0) {
            elementData = new Object[1];
        } else {
            elementData = new Object[initialCapacity];
        }
    }

    /** Inserts an element at the given index */
    public void add(int index, Object element) {

//        reporter.updateCounter++;
        if (index > elementCount) {
            throw new IndexOutOfBoundsException("Index out of bounds: "
                                                + index + ">" + elementCount);
        }

        if (index < 0) {
            throw new IndexOutOfBoundsException("Index out of bounds: "
                                                + index + " < 0");
        }

        if (elementCount >= elementData.length) {
            increaseCapacity();
        }

        for (int i = elementCount; i > index; i--) {
            elementData[i] = elementData[i - 1];
        }

        elementData[index] = element;

        elementCount++;
    }

    /** Appends an element to the end of the list */
    public boolean add(Object element) {

//        reporter.updateCounter++;
        if (elementCount >= elementData.length) {
            increaseCapacity();
        }

        elementData[elementCount] = element;

        elementCount++;

        return true;
    }

    /** Gets the element at given position */
    public Object get(int index) {

        if (index >= elementCount) {
            throw new IndexOutOfBoundsException("Index out of bounds: "
                                                + index + " >= "
                                                + elementCount);
        }

        if (index < 0) {
            throw new IndexOutOfBoundsException("Index out of bounds: "
                                                + index + " < 0");
        }

        return elementData[index];
    }

    /** returns the index of given object or -1 if nt found */
    public int indexOf(Object o) {

        for (int i = 0; i < elementCount; i++) {
            if (elementData[i].equals(o)) {
                return i;
            }
        }

        return -1;
    }

    /** Removes and returns the element at given position */
    public Object remove(int index) {

        if (index >= elementCount) {
            throw new IndexOutOfBoundsException("Index out of bounds: "
                                                + index + " >= "
                                                + elementCount);
        }

        if (index < 0) {
            throw new IndexOutOfBoundsException("Index out of bounds: "
                                                + index + " < 0");
        }

        Object removedObj = elementData[index];

        for (int i = index; i < elementCount - 1; i++) {
            elementData[i] = elementData[i + 1];
        }

        elementCount--;

        elementData[elementCount] = null;

        if (minimizeOnClear && elementCount == 0) {
            elementData = new Object[DEFAULT_INITIAL_CAPACITY];
        }

        return removedObj;
    }

    /** Replaces the element at given position */
    public Object set(int index, Object element) {

        if (index >= elementCount) {
            throw new IndexOutOfBoundsException("Index out of bounds: "
                                                + index + " >= "
                                                + elementCount);
        }

        if (index < 0) {
            throw new IndexOutOfBoundsException("Index out of bounds: "
                                                + index + " < 0");
        }

        Object replacedObj = elementData[index];

        elementData[index] = element;

        return replacedObj;
    }

    /** Returns the number of elements in the array list */
    public final int size() {
        return elementCount;
    }

    private void increaseCapacity() {

        int baseSize = elementData.length == 0 ? 1
                                               : elementData.length;
        Object[] newArray =
            new Object[(int) (baseSize * DEFAULT_RESIZE_FACTOR)];

        System.arraycopy(elementData, 0, newArray, 0, elementData.length);

        elementData = newArray;
        newArray    = null;
    }

    /**
     * Returns an Enumeration of the elements of the list.  The Enumerator will
     * NOT throw a concurrent modification exception if the list is modified
     * during the enumeration.
     */
/*
    public Enumeration elements() {

        Enumeration en = new Enumeration() {

            private int pos = 0;

            public Object nextElement() {

                if (!hasMoreElements()) {
                    throw new NoSuchElementException("Enumeration complete");
                }

                pos++;

                return elementData[pos - 1];
            }

            public boolean hasMoreElements() {
                return (pos < elementCount);
            }
        };

        return en;
    }
*/

    /** Trims the array to be the same size as the number of elements. */
    public void trim() {

        // 0 size array is possible
        Object[] newArray = new Object[elementCount];

        System.arraycopy(elementData, 0, newArray, 0, elementCount);

        elementData = newArray;
        newArray    = null;
    }

    // fredt@users
    public void clear() {

        if (minimizeOnClear
                && elementData.length > DEFAULT_INITIAL_CAPACITY) {
            elementData  = new Object[DEFAULT_INITIAL_CAPACITY];
            elementCount = 0;

            return;
        }

        for (int i = 0; i < elementCount; i++) {
            elementData[i] = null;
        }

        elementCount = 0;
    }

    public void setSize(int newSize) {

        if (newSize < elementCount) {
            if (minimizeOnClear && newSize == 0
                    && elementData.length > DEFAULT_INITIAL_CAPACITY) {
                elementData  = new Object[DEFAULT_INITIAL_CAPACITY];
                elementCount = 0;

                return;
            }

            for (int i = newSize; i < elementCount; i++) {
                elementData[i] = null;
            }
        }

        elementCount = newSize;

        for (; elementCount > elementData.length; ) {
            increaseCapacity();
        }
    }

// fredt@users
    public Object[] toArray() {

        Object[] a = new Object[elementCount];

        System.arraycopy(elementData, 0, a, 0, elementCount);

        return a;
    }

    public Object[] toArray(int start, int limit) {

        Object[] a = new Object[elementCount - limit];

        System.arraycopy(elementData, start, a, 0, elementCount - limit);

        return a;
    }

    /**
     * Copies all elements of the list to a[]. It is assumed a[] is of the
     * correct type. If a[] is too small, a new array or the same type is
     * returned. If a[] is larger, only the list elements are copied and no
     * other change is made to the array.
     * Differs from the implementation in java.util.ArrayList in the second
     * aspect.
     */
    public Object toArray(Object a) {

        if (Array.getLength(a) < elementCount) {
            a = Array.newInstance(a.getClass().getComponentType(),
                                  elementCount);
        }

        System.arraycopy(elementData, 0, a, 0, elementCount);

        return a;
    }

    public void sort(ObjectComparator c) {

        if (elementCount < 2) {
            return;
        }

        Sort.sort(elementData, c, 0, elementCount - 1);
    }

    public Object[] getArray() {
        return elementData;
    }
}