recordstore.java

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/*
 *
 *
 * Copyright  1990-2008 Sun Microsystems, Inc. All Rights Reserved.
 * 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.
 */

package javax.microedition.rms;

import com.sun.midp.midlet.MIDletSuite;
import com.sun.midp.midlet.MIDletStateHandler;

import com.sun.midp.midletsuite.MIDletSuiteStorage;

import com.sun.midp.rms.RecordStoreImpl;
import com.sun.midp.rms.RecordStoreEventConsumer;
import com.sun.midp.rms.RecordStoreRegistry;

import com.sun.midp.security.SecurityInitializer;
import com.sun.midp.security.SecurityToken;
import com.sun.midp.security.ImplicitlyTrustedClass;

import com.sun.midp.log.Logging;
import com.sun.midp.log.LogChannels;

/**
 * A class representing a record store. A record store consists of a
 * collection of records which will remain persistent across multiple
 * invocations of the MIDlet. The platform is responsible for
 * making its best effort to maintain the integrity of the
 * MIDlet's record stores throughout the normal use of the
 * platform, including reboots, battery changes, etc.
 *
 * <p>Record stores are created in platform-dependent locations, which
 * are not exposed to the MIDlets. The naming space for record stores
 * is controlled at the MIDlet suite granularity. MIDlets within a
 * MIDlet suite are allowed to create multiple record stores, as long
 * as they are each given different names. When a MIDlet suite is
 * removed from a platform all the record stores associated with its
 * MIDlets will also be removed. MIDlets within a MIDlet suite can
 * access each other's record stores directly. New APIs in MIDP
 * allow for the explicit sharing of record stores if the MIDlet
 * creating the RecordStore chooses to give such permission.</p>
 *
 * <p> Sharing is accomplished through the ability to name a
 * RecordStore created by another MIDlet suite.</p>
 *
 * <P> RecordStores are uniquely named using the unique name of the
 * MIDlet suite plus the name of the RecordStore. MIDlet suites are
 * identified by the MIDlet-Vendor and MIDlet-Name attributes from the
 * application descriptor.</p>
 *
 * <p> Access controls are defined when RecordStores to be shared are
 * created. Access controls are enforced when RecordStores are
 * opened. The access modes allow private use or shareable
 * with any other MIDlet suite.</p>
 *
 * <p>Record store names are case sensitive and may consist of any
 * combination of between one and 32 Unicode characters
 * inclusive. Record store names must be unique within the scope of a
 * given MIDlet suite. In other words, MIDlets within a MIDlet suite
 * are not allowed to create more than one record store with the same
 * name, however a MIDlet in one MIDlet suite is allowed to have a
 * record store with the same name as a MIDlet in another MIDlet
 * suite. In that case, the record stores are still distinct and
 * separate.</p>
 *
 * <p>No locking operations are provided in this API. Record store
 * implementations ensure that all individual record store operations
 * are atomic, synchronous, and serialized, so no corruption will
 * occur with multiple accesses. However, if a MIDlet uses multiple
 * threads to access a record store, it is the MIDlet's responsibility
 * to coordinate this access or unintended consequences may result.
 * Similarly, if a platform performs transparent synchronization of a
 * record store, it is the platform's responsibility to enforce
 * exclusive access to the record store between the MIDlet and
 * synchronization engine.</p>
 *
 * <p>Records are uniquely identified within a given record store by
 * their recordId, which is an integer value. This recordId is used as
 * the primary key for the records. The first record created in a
 * record store will have recordId equal to one (1). Each subsequent
 * record added to a RecordStore will be assigned a recordId one
 * greater than the record added before it. That is, if two records
 * are added to a record store, and the first has a recordId of 'n',
 * the next will have a recordId of 'n + 1'. MIDlets can create other
 * sequences of the records in the RecordStore by using the
 * <code>RecordEnumeration</code> class.</p>
 *
 * <p>This record store uses long integers for time/date stamps, in
 * the format used by System.currentTimeMillis(). The record store is
 * time stamped with the last time it was modified. The record store
 * also maintains a <em>version</em> number, which is an integer that
 * is incremented for each operation that modifies the contents of the
 * RecordStore.  These are useful for synchronization engines as well
 * as other things.</p>
 *
 * @since MIDP 1.0
 */

public class RecordStore {

    /** Record store change types */
    final static int RECORD_CHANGED = 1;
    final static int RECORD_ADDED = 2;
    final static int RECORD_DELETED = 3;    

    /** cache of open RecordStore instances */
    private static java.util.Vector openRecordStores = new java.util.Vector(3);

    /** The peer that performs the real functionallity. */
    private RecordStoreImpl peer;

    /** name of this record store */
    private String recordStoreName;

    /** unique id for suite that owns this record store */
    private int suiteId;

    /** number of open instances of this record store */
    private int opencount;

    /** recordListeners of this record store */
    private java.util.Vector recordListeners;

    /**
     * Inner class to request security token from SecurityInitializer.
     * SecurityInitializer should be able to check this inner class name.
     */
    static private class SecurityTrusted
        implements ImplicitlyTrustedClass {};

    /**
     * The security token necessary to use RecordStoreImpl.
     * This is initialized in a static initialization block.
     */
    private static SecurityToken classSecurityToken =
        SecurityInitializer.requestToken(new SecurityTrusted());

    /** Consumer of record store change events */
    private static RecordStoreEventConsumer recordStoreEventConsumer;

    /*
     * RecordStore Constructors
     */

    /**
     * MIDlets must use <code>openRecordStore()</code> to get
     * a <code>RecordStore</code> object. If this constructor
     * is not declared (as private scope), Javadoc (and Java)
     * will assume a public constructor.
     *
     * @param suiteId the ID of the suite that owns this record store
     * @param recordStoreName the MIDlet suite unique name for the
     *          record store, consisting of between one and 32 Unicode
     *          characters inclusive.
     */
    private RecordStore(int suiteId, String recordStoreName) {
        this.suiteId = suiteId;
        this.recordStoreName = recordStoreName;
        recordListeners = new java.util.Vector(3);
    }

    /**
     * Deletes the named record store. MIDlet suites are only allowed
     * to delete their own record stores. If the named record store is
     * open (by a MIDlet in this suite or a MIDlet in a different
     * MIDlet suite) when this method is called, a
     * RecordStoreException will be thrown.  If the named record store
     * does not exist a RecordStoreNotFoundException will be
     * thrown. Calling this method does NOT result in recordDeleted
     * calls to any registered listeners of this RecordStore.
     *
     * @param recordStoreName the MIDlet suite unique record store to
     *          delete
     *
     * @exception RecordStoreException if a record store-related
     *          exception occurred
     * @exception RecordStoreNotFoundException if the record store
     *          could not be found
     */
    public static void deleteRecordStore(String recordStoreName)
        throws RecordStoreException, RecordStoreNotFoundException {
        int id = MIDletStateHandler.getMidletStateHandler().
            getMIDletSuite().getID();

        if (recordStoreName == null || recordStoreName.length() == 0) {
            throw new RecordStoreNotFoundException();
        }

        // Check the record store cache for a db with the same name
        synchronized (openRecordStores) {
            RecordStore db;
            int size = openRecordStores.size();
            for (int n = 0; n < size; n++) {
                db = (RecordStore) openRecordStores.elementAt(n);
                if (db.suiteId == id &&
                    db.recordStoreName.equals(recordStoreName)) {
                    // cannot delete an open record store
                    throw new RecordStoreException("deleteRecordStore error:"
                        + " record store is"
                        + " still open");
                }
            }

            // this record store is not currently open
            RecordStoreImpl.deleteRecordStore(
                classSecurityToken, id, recordStoreName);

        }
    }

    /**
     * Open (and possibly create) a record store associated with the
     * given MIDlet suite. If this method is called by a MIDlet when
     * the record store is already open by a MIDlet in the MIDlet suite,
     * this method returns a reference to the same RecordStore object.
     *
     * @param recordStoreName the MIDlet suite unique name for the
     *          record store, consisting of between one and 32 Unicode
     *          characters inclusive.
     * @param createIfNecessary if true, the record store will be
     *          created if necessary
     *
     * @return <code>RecordStore</code> object for the record store
     *
     * @exception RecordStoreException if a record store-related
     *          exception occurred
     * @exception RecordStoreNotFoundException if the record store
     *          could not be found
     * @exception RecordStoreFullException if the operation cannot be
     *          completed because the record store is full
     * @exception IllegalArgumentException if
     *          recordStoreName is invalid
     */
    public static RecordStore openRecordStore(String recordStoreName,
                                              boolean createIfNecessary)
        throws RecordStoreException, RecordStoreFullException,
        RecordStoreNotFoundException {

        int id = MIDletStateHandler.getMidletStateHandler().
            getMIDletSuite().getID();

        return doOpen(id, recordStoreName, createIfNecessary);
    }

    /**
     * Open (and possibly create) a record store that can be shared
     * with other MIDlet suites. The RecordStore is owned by the
     * current MIDlet suite. The authorization mode is set when the
     * record store is created, as follows:
     *
     * <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.</p>
     *
     * <p> If this method is called by a MIDlet when the record store
     * is already open by a MIDlet in the MIDlet suite, this method
     * returns a reference to the same RecordStore object.</p>
     *
     * @param recordStoreName the MIDlet suite unique name for the
     *          record store, consisting of between one and 32 Unicode
     *          characters inclusive.
     * @param createIfNecessary if true, the record store will be
     *          created if necessary
     * @param authmode the mode under which to check or create access.
     *          Must be one of AUTHMODE_PRIVATE or AUTHMODE_ANY.
     *          This argument is ignored if the RecordStore exists.
     * @param writable true if the RecordStore is to be writable by
     *          other MIDlet suites that are granted access.
     *          This argument is ignored if the RecordStore exists.
     *
     * @return <code>RecordStore</code> object for the record store
     *
     * @exception RecordStoreException if a record store-related
     *          exception occurred
     * @exception RecordStoreNotFoundException if the record store
     *          could not be found
     * @exception RecordStoreFullException if the operation
     *          cannot be completed because the record store is full
     * @exception IllegalArgumentException if authmode or
     *          recordStoreName is invalid
     */
    public static RecordStore openRecordStore(String recordStoreName,
                                              boolean createIfNecessary,
                                              int authmode,
                                              boolean writable)
        throws RecordStoreException, RecordStoreFullException,
               RecordStoreNotFoundException {
        RecordStore recordStore;
        boolean isExistingStorage = false;

        /*
         * First, we have to check if the record store already exists or not.
         * If we open an existing record store, "authmode" must be ignored!
         *
         */
        try {
            recordStore = openRecordStore(recordStoreName, false);
            isExistingStorage = true;