database.java

hsqldb是100％java实现的数据库,是一个开放源代码的JAVA数据库 l 具有标准的SQL语法和JAVA接口 l HSQLDB可以自由使用和分发 l 非常简洁和快速的

/* Copyright (c) 1995-2000, The Hypersonic SQL 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 Hypersonic SQL 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 THE HYPERSONIC SQL GROUP,
 * 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.
 *
 * This software consists of voluntary contributions made by many individuals 
 * on behalf of the Hypersonic SQL Group.
 *
 *
 * For work added by the HSQL Development Group:
 *
 * 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;

import java.lang.reflect.Constructor;

import org.hsqldb.lib.FileAccess;
import org.hsqldb.lib.FileUtil;
import org.hsqldb.lib.HashMap;
import org.hsqldb.persist.HsqlDatabaseProperties;
import org.hsqldb.persist.HsqlProperties;
import org.hsqldb.persist.Logger;

// fredt@users 20020130 - patch 476694 by velichko - transaction savepoints
// additions to different parts to support savepoint transactions
// fredt@users 20020215 - patch 1.7.0 - new HsqlProperties class
// support use of properties from database.properties file
// fredt@users 20020218 - patch 1.7.0 - DEFAULT keyword
// support for default values for table columns
// fredt@users 20020305 - patch 1.7.0 - restructuring
// some methods move to Table.java, some removed
// fredt@users 20020221 - patch 513005 by sqlbob@users (RMP) - restructuring
// fredt@users 20020221 - patch 513005 by sqlbob@users (RMP) - error trapping
// boucherb@users 20020130 - patch 1.7.0 - use lookup for speed
// idents listed in alpha-order for easy check of stats...
// fredt@users 20020420 - patch523880 by leptipre@users - VIEW support
// boucherb@users - doc 1.7.0 - added javadoc comments
// tony_lai@users 20020820 - patch 595073 - duplicated exception msg
// tony_lai@users 20020820 - changes to shutdown compact to save memory
// boucherb@users 20020828 - allow reconnect to local db that has shutdown
// fredt@users 20020912 - patch 1.7.1 by fredt - drop duplicate name triggers
// fredt@users 20021112 - patch 1.7.2 by Nitin Chauhan - use of switch
// rewrite of the majority of multiple if(){}else if(){} chains with switch()
// boucherb@users 20020310 - class loader update for JDK 1.1 compliance
// fredt@users 20030401 - patch 1.7.2 by akede@users - data files readonly
// fredt@users 20030401 - patch 1.7.2 by Brendan Ryan - data files in Jar
// boucherb@users 20030405 - removed 1.7.2 lint - updated JavaDocs
// boucherb@users 20030425 - DDL methods are moved to DatabaseCommandInterpreter.java
// boucherb@users - fredt@users 200305..200307 - patch 1.7.2 - DatabaseManager upgrade
// loosecannon1@users - patch 1.7.2 - properties on the JDBC URL
// [e-mail] - changed to file access api

/**
 *  Database is the root class for HSQL Database Engine database. <p>
 *
 *  It holds the data structure that form an HSQLDB database instance.
 *
 * Modified significantly from the Hypersonic original in successive
 * HSQLDB versions.
 *
 * @author Thomas Mueller (Hypersonic SQL Group)
 * @version 1.8.0
 * @since Hypersonic SQL
 */
public class Database {

    int    databaseID;
    String sType;
    String sName;

// loosecannon1@users 1.7.2 patch properties on the JDBC URL
    private HsqlProperties urlProperties;
    private String         sPath;
    DatabaseInformation    dbInfo;
    ClassLoader            classLoader;

    /** indicates the state of the database */
    private int   dbState;
    public Logger logger;

    /** true means that all tables are readonly. */
    boolean databaseReadOnly;

    /**
     * true means that all CACHED and TEXT tables are readonly.
     *  MEMORY tables are updatable but updates are not persisted.
     */
    private boolean filesReadOnly;

    /** true means filesReadOnly but CACHED and TEXT tables are disallowed */
    private boolean                filesInJar;
    public boolean                 sqlEnforceStrictSize;
    public int                     firstIdentity;
    private boolean                bIgnoreCase;
    private boolean                bReferentialIntegrity;
    private HsqlDatabaseProperties databaseProperties;
    private boolean                shutdownOnNoConnection;

    // schema invarient objects
    private HashMap        hAlias;
    public UserManager     userManager;
    public GranteeManager  granteeManager;
    public HsqlNameManager nameManager;

    // session related objects
    public SessionManager     sessionManager;
    public TransactionManager txManager;
    CompiledStatementManager  compiledStatementManager;

    // schema objects
    public SchemaManager schemaManager;
    public Collation     collation;

    //
    public static final int DATABASE_ONLINE       = 1;
    public static final int DATABASE_OPENING      = 4;
    public static final int DATABASE_CLOSING      = 8;
    public static final int DATABASE_SHUTDOWN     = 16;
    public static final int CLOSEMODE_IMMEDIATELY = -1;
    public static final int CLOSEMODE_NORMAL      = 0;
    public static final int CLOSEMODE_COMPACT     = 1;
    public static final int CLOSEMODE_SCRIPT      = 2;

    /**
     *  Constructs a new Database object.
     *
     * @param type is the type of the database: "mem", "file", "res"
     * @param path is the fiven path to the database files
     * @param name is the combination of type and canonical path
     * @param props property overrides placed on the connect URL
     * @exception  HsqlException if the specified name and path
     *      combination is illegal or unavailable, or the database files the
     *      name and path resolves to are in use by another process
     */
    Database(String type, String path, String name,
             HsqlProperties props) throws HsqlException {

        urlProperties = props;

        setState(Database.DATABASE_SHUTDOWN);

        sName = name;
        sType = type;
        sPath = path;

        if (sType == DatabaseURL.S_RES) {
            filesInJar    = true;
            filesReadOnly = true;
        }

        // does not need to be done more than once
        try {
            classLoader = getClass().getClassLoader();
        } catch (Exception e) {

            // strict security policy:  just use the system/boot loader
            classLoader = null;
        }

// [e-mail] - changed to file access api
        String fileaccess_class_name =
            (String) urlProperties.getProperty("fileaccess_class_name");

        if (fileaccess_class_name != null) {
            String storagekey = urlProperties.getProperty("storage_key");

            try {
                Class zclass = Class.forName(fileaccess_class_name);
                Constructor constructor = zclass.getConstructor(new Class[]{
                    Object.class });

                fileaccess =
                    (FileAccess) constructor.newInstance(new Object[]{
                        storagekey });
                isStoredFileAccess = true;
            } catch (java.lang.ClassNotFoundException e) {
                System.out.println("ClassNotFoundException");
            } catch (java.lang.InstantiationException e) {
                System.out.println("InstantiationException");
            } catch (java.lang.IllegalAccessException e) {
                System.out.println("IllegalAccessException");
            } catch (Exception e) {
                System.out.println("Exception");
            }
        } else {
            fileaccess = FileUtil.getDefaultInstance();
        }

        shutdownOnNoConnection = urlProperties.getProperty("shutdown",
                "false").equals("true");
        logger                   = new Logger();
        compiledStatementManager = new CompiledStatementManager(this);
    }

    /**
     * Opens this database.  The database should be opened after construction.
     */
    synchronized void open() throws HsqlException {

        if (!isShutdown()) {
            return;
        }

        reopen();
    }

    /**
     * Opens this database.  The database should be opened after construction.
     * or reopened by the close(int closemode) method during a
     * "shutdown compact". Closes the log if there is an error.
     */
    void reopen() throws HsqlException {

        boolean isNew;

        setState(DATABASE_OPENING);

        try {
            databaseProperties = new HsqlDatabaseProperties(this);
            isNew = !DatabaseURL.isFileBasedDatabaseType(sType)
                    ||!databaseProperties.checkFileExists();

            if (isNew && urlProperties.isPropertyTrue("ifexists")) {
                throw Trace.error(Trace.DATABASE_NOT_EXISTS, sName);
            }

            databaseProperties.load();
            databaseProperties.setURLProperties(urlProperties);
            compiledStatementManager.reset();

            nameManager           = new HsqlNameManager();
            granteeManager        = new GranteeManager(this);
            userManager           = new UserManager(this);
            hAlias                = Library.getAliasMap();
            schemaManager         = new SchemaManager(this);
            bReferentialIntegrity = true;
            sessionManager        = new SessionManager(this);
            txManager             = new TransactionManager(this);
            collation             = new Collation();
            dbInfo = DatabaseInformation.newDatabaseInformation(this);

            databaseProperties.setDatabaseVariables();

            if (DatabaseURL.isFileBasedDatabaseType(sType)) {
                logger.openLog(this);
            }

            if (isNew) {
                sessionManager.getSysSession().sqlExecuteDirectNoPreChecks(
                    "CREATE USER SA PASSWORD \"\" ADMIN");
                logger.synchLogForce();
            }

            dbInfo.setWithContent(true);
        } catch (Throwable e) {
            logger.closeLog(Database.CLOSEMODE_IMMEDIATELY);
            logger.releaseLock();
            setState(DATABASE_SHUTDOWN);
            clearStructures();
            DatabaseManager.removeDatabase(this);

            if (!(e instanceof HsqlException)) {
                e = Trace.error(Trace.GENERAL_ERROR, e.toString());
            }

            throw (HsqlException) e;
        }

        setState(DATABASE_ONLINE);
    }

    /**
     * Clears the data structuress, making them elligible for garbage collection.
     */
    void clearStructures() {

        if (schemaManager != null) {
            schemaManager.clearStructures();
        }

        granteeManager = null;
        userManager    = null;
        hAlias         = null;
        nameManager    = null;
        schemaManager  = null;
        sessionManager = null;
        dbInfo         = null;
    }

    /**