abstractrecordstoreimpl.java

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/*
 *
 *
 * Portions Copyright  2000-2007 Sun Microsystems, Inc. All Rights
 * Reserved.  Use is subject to license terms.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 only, as published by the Free Software Foundation.
 * 
 * This program 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 version 2 for more details (a copy is
 * included at /legal/license.txt).
 * 
 * You should have received a copy of the GNU General Public License
 * version 2 along with this work; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 * 
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
 * Clara, CA 95054 or visit www.sun.com if you need additional
 * information or have any questions.
 *
 * Copyright 2000 Motorola, Inc. All Rights Reserved.
 * This notice does not imply publication.
 */

package com.sun.midp.rms;

import java.io.IOException;

import javax.microedition.rms.InvalidRecordIDException;
import javax.microedition.rms.RecordStoreException;
import javax.microedition.rms.RecordStoreFullException;
import javax.microedition.rms.RecordStoreNotOpenException;

/**
 * An interface for a record store implementation.
 */

interface AbstractRecordStoreImpl {
    /*
     * The layout of the database file is as follows:
     *
     * Bytes - Usage
     * 00-07 - Signature = 'midp-rms'
     * 08-11 - Authmode and Writable state info
     * 12-15 - Next record ID to use (big endian)
     * 16-19 - Number of live records in the database (big endian)
     * 20-23 - Database "version" - a monotonically increasing revision
     *         number (big endian)
     * 24-31 - Last modified (64-bit long, big endian, milliseconds since
     *         jan 1970)
     * 32-35 - Size of Data storage (big endian)
     * 36-39 - Size of Free storage (big endian)
     * 40-xx - Record storage
     */

    /** RS_SIGNATURE offset */
    static final int RS0_SIGNATURE = 0;

    /** RS_AUTHMODE offset */
    static final int RS1_AUTHMODE = 8;

    /** RS_NEXT_ID offset */
    static final int RS2_NEXT_ID = 12;

    /** RS_NUM_LIVE offset */
    static final int RS3_NUM_LIVE = 16;

    /** RS_VERSION offset */
    static final int RS4_VERSION = 20;

    /** RS_LAST_MODIFIED offset */
    static final int RS5_LAST_MODIFIED = 24;

    /** RS_START_OF_DATA offset */
    static final int RS6_DATA_SIZE = 32;

    /** RS_START_OF_DATA offset */
    static final int RS7_FREE_SIZE = 36;

    /** Size of the db header */
    static final int DB_HEADER_SIZE = 40;

    /** pre initialized RecordStore header structure */
    static final byte[] DB_SIGNATURE = {
        (byte)'m', (byte)'i', (byte)'d', (byte)'p',
        (byte)'-', (byte)'r', (byte)'m', (byte)'s'
    };

    /** used to compact the records of the record store */
    static final int COMPACT_BUFFER_SIZE = 1024;

    /**
     *  Each block starts with an 8 byte header
     *    First 4 bytes is the recordId or -1 if it is a free block
     *    Second 4 bytes is the size of the data in the block
     *    The data immediately follows the header
     *    If the length of the data is not a multiple of 8 the data is padded
     *
     *  Things that need to be done by the header code
     *
     */
    /** Size of the block header */
    static final int BLOCK_HEADER_SIZE = 8;

    /**
     * Internal indicator for AUTHMODE_ANY with read only access
     * AUTHMODE_ANY_RO has a value of 2.
     */
    final static int AUTHMODE_ANY_RO = 2;

    /**
     * Changes the access mode for this RecordStore. The authorization
     * mode choices are:
     *
     * <ul>
     * <li><code>AUTHMODE_PRIVATE</code> - Only allows the MIDlet
     *          suite that created the RecordStore to access it. This
     *          case behaves identically to
     *          <code>openRecordStore(recordStoreName,
     *          createIfNecessary)</code>.</li>
     * <li><code>AUTHMODE_ANY</code> - Allows any MIDlet to access the
     *          RecordStore. Note that this makes your recordStore
     *          accessible by any other MIDlet on the device. This
     *          could have privacy and security issues depending on
     *          the data being shared. Please use carefully.</li>
     * </ul>
     *
     * <p>The owning MIDlet suite may always access the RecordStore and
     * always has access to write and update the store. Only the
     * owning MIDlet suite can change the mode of a RecordStore.</p>
     *
     * @param authmode the mode under which to check or create access.
     *          Must be one of AUTHMODE_PRIVATE or AUTHMODE_ANY.
     * @param writable true if the RecordStore is to be writable by
     *          other MIDlet suites that are granted access
     *
     * @exception RecordStoreException if a record store-related
     *          exception occurred
     * @exception SecurityException if this MIDlet Suite is not
     *          allowed to change the mode of the RecordStore
     * @exception IllegalArgumentException if authmode is invalid
     */
    void setMode(int authmode, boolean writable)
        throws RecordStoreException;

    /**
     * This method is called when the MIDlet requests to have the
     * record store closed. Note that the record store will not
     * actually be closed until closeRecordStore() is called as many
     * times as openRecordStore() was called. In other words, the
     * MIDlet needs to make a balanced number of close calls as open
     * calls before the record store is closed.
     *
     * <p>When the record store is closed, all listeners are removed
     * and all RecordEnumerations associated with it become invalid.
     * If the MIDlet attempts to perform
     * operations on the RecordStore object after it has been closed,
     * the methods will throw a RecordStoreNotOpenException.
     *
     * @exception RecordStoreNotOpenException if the record store is
     *          not open
     * @exception RecordStoreException if a different record
     *          store-related exception occurred
     */
    void closeRecordStore()
        throws RecordStoreNotOpenException, RecordStoreException;

    /**
     * Get the authorization mode for this record store.
     *
     * @return authorization mode
     */
    int getAuthMode();

    /**
     * Each time a record store is modified (by
     * <code>addRecord</code>, <code>setRecord</code>, or
     * <code>deleteRecord</code> methods) its <em>version</em> is
     * incremented. This can be used by MIDlets to quickly tell if
     * anything has been modified.
     *
     * The initial version number is implementation dependent.
     * The increment is a positive integer greater than 0.
     * The version number increases only when the RecordStore is updated.
     *
     * The increment value need not be constant and may vary with each
     * update.
     *
     * @return the current record store version
     */
    int getVersion() throws RecordStoreNotOpenException;

    /**
     * Returns the number of records currently in the record store.
     *
     * @return the number of records currently in the record store
     */
    int getNumRecords();

    /**
     * Returns the amount of space, in bytes, that the record store
     * occupies. The size returned includes any overhead associated