doubleintindex.java

hsql是很有名的嵌入式数据库

/* Copyright (c) 2001-2005, 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.util.NoSuchElementException;

/**
 * Maintains an ordered  integer->integer lookup table, consisting of two
 * columns, one for keys, the other for values.
 *
 * The table is sorted on either the key or value column, depending on the calls to
 * setKeysSearchTarget() or setValuesSearchTarget(). By default, the table is
 * sorted on values.<p>
 *
 * findXXX() methods return the array index into the list
 * pair containing a matching key or value, or  or -1 if not found.<p>
 *
 * Sorting methods originally contributed by Tony Lai.
 *
 * @author fredt@users
 * @version 1.8.0
 * @since 1.8.0
 */
public class DoubleIntIndex implements IntLookup {

    private int           count = 0;
    private int           capacity;
    private boolean       sorted       = true;
    private boolean       sortOnValues = true;
    private boolean       hasChanged;
    private final boolean fixedSize;
    private int[]         keys;
    private int[]         values;

//
    private int targetSearchValue;

    public DoubleIntIndex(int capacity, boolean fixedSize) {

        this.capacity  = capacity;
        keys           = new int[capacity];
        values         = new int[capacity];
        this.fixedSize = fixedSize;
        hasChanged     = true;
    }

    public synchronized int getKey(int i) {

        if (i < 0 || i >= count) {
            throw new IndexOutOfBoundsException();
        }

        return keys[i];
    }

    public synchronized int getValue(int i) {

        if (i < 0 || i >= count) {
            throw new IndexOutOfBoundsException();
        }

        return values[i];
    }

    /**
     * Modifies an existing pair.
     * @param i the index
     * @param key the key
     */
    public synchronized void setKey(int i, int key) {

        if (i < 0 || i >= count) {
            throw new IndexOutOfBoundsException();
        }

        if (!sortOnValues) {
            sorted = false;
        }

        keys[i] = key;
    }

    /**
     * Modifies an existing pair.
     * @param i the index
     * @param value the value
     */
    public synchronized void setValue(int i, int value) {

        if (i < 0 || i >= count) {
            throw new IndexOutOfBoundsException();
        }

        if (sortOnValues) {
            sorted = false;
        }

        values[i] = value;
    }

    public synchronized int size() {
        return count;
    }

    public synchronized int capacity() {
        return capacity;
    }

    /**
     * Adds a pair into the table.
     *
     * @param key the key
     * @param value the value
     * @return true or false depending on success
     */
    public synchronized boolean addUnsorted(int key, int value) {

        if (count == capacity) {
            if (fixedSize) {
                return false;
            } else {
                doubleCapacity();
            }
        }

        if (sorted && count != 0) {
            if (sortOnValues) {
                if (value < values[count - 1]) {
                    sorted = false;
                }
            } else {
                if (value < keys[count - 1]) {
                    sorted = false;
                }
            }
        }

        hasChanged    = true;
        keys[count]   = key;
        values[count] = value;

        count++;

        return true;
    }

    /**
     * Adds a key, value pair into the table with the guarantee that the key
     * is equal or larger than the largest existing key. This prevents a sort
     * from taking place on next call to find()
     *
     * @param key the key
     * @param value the value
     * @return true or false depending on success
     */
    public synchronized boolean addSorted(int key, int value) {

        if (count == capacity) {
            if (fixedSize) {
                return false;
            } else {
                doubleCapacity();
            }
        }

        if (count != 0 && value < values[count - 1]) {
            return false;
        }

        hasChanged    = true;
        keys[count]   = key;
        values[count] = value;

        count++;

        return true;
    }

    /**
     * Adds a pair, ensuring no duplicate key xor value already exists in the
     * current search target column.
     * @param key the key
     * @param value the value
     * @return true or false depending on success
     */
    public synchronized boolean addUnique(int key, int value) {

        if (count == capacity) {
            if (fixedSize) {
                return false;
            } else {
                doubleCapacity();
            }
        }

        if (!sorted) {
            fastQuickSort();
        }

        targetSearchValue = sortOnValues ? value
                                         : key;

        int i = binaryEmptySlotSearch();

        if (i == -1) {
            return false;
        }

        hasChanged = true;

        if (count != i) {
            moveRows(i, i + 1, count - i);
        }

        keys[i]   = key;
        values[i] = value;

        count++;

        return true;
    }

    /**
     * Adds a pair, maintaining sorted order
     * current search target column.
     * @param key the key
     * @param value the value
     * @return true or false depending on success
     */
    public synchronized boolean add(int key, int value) {

        if (count == capacity) {
            if (fixedSize) {
                return false;
            } else {
                doubleCapacity();
            }
        }

        if (!sorted) {
            fastQuickSort();
        }

        targetSearchValue = sortOnValues ? value
                                         : key;

        int i = binarySlotSearch();

        if (i == -1) {
            return false;
        }

        hasChanged = true;

        if (count != i) {
            moveRows(i, i + 1, count - i);
        }

        keys[i]   = key;
        values[i] = value;

        count++;

        return true;
    }

    public int lookupFirstEqual(int key) throws NoSuchElementException {

        if (sortOnValues) {
            sorted       = false;
            sortOnValues = false;
        }

        int i = findFirstEqualKeyIndex(key);

        if (i == -1) {
            throw new NoSuchElementException();
        }

        return getValue(i);
    }

    public int lookupFirstGreaterEqual(int key)
    throws NoSuchElementException {

        if (sortOnValues) {
            sorted       = false;
            sortOnValues = false;
        }

        int i = findFirstGreaterEqualKeyIndex(key);

        if (i == -1) {
            throw new NoSuchElementException();
        }

        return getValue(i);
    }

    public synchronized void setValuesSearchTarget() {

        if (!sortOnValues) {
            sorted = false;
        }

        sortOnValues = true;
    }

    public synchronized void setKeysSearchTarget() {

        if (sortOnValues) {
            sorted = false;
        }