databasecommandinterpreter.java

hsql是很有名的嵌入式数据库

/* 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.io.IOException;
import java.io.LineNumberReader;
import java.io.StringReader;
import java.util.Locale;

import org.hsqldb.HsqlNameManager.HsqlName;
import org.hsqldb.lib.ArrayUtil;
import org.hsqldb.lib.HashSet;
import org.hsqldb.lib.HsqlArrayList;
import org.hsqldb.lib.StringUtil;
import org.hsqldb.lib.java.JavaSystem;
import org.hsqldb.persist.HsqlDatabaseProperties;
import org.hsqldb.scriptio.ScriptWriterBase;
import org.hsqldb.scriptio.ScriptWriterText;

/**
 * Provides SQL Interpreter services relative to a Session and
 * its Database.
 *
 * The core functionality of this class was inherited from Hypersonic and
 * extensively rewritten and extended in successive versions of HSQLDB.
 *
 * @author Thomas Mueller (Hypersonic SQL Group)
 * @version 1.8.0
 * @since 1.7.2
 */

// fredt@users 20020221 - patch 513005 by sqlbob@users (RMP) - various corrections
// fredt@users 20020430 - patch 549741 by velichko - ALTER TABLE RENAME
// fredt@users 20020405 - patch 1.7.0 - other ALTER TABLE statements
// tony_lai@users 20020820 - patch 595099 - use user-defined PK name
// tony_lai@users 20020820 - patch 595156 - violation of constraint name
// fredt@users 20020912 - patch 1.7.1 by fredt - log alter statements
// kloska@users 20021030 - patch 1.7.2 - ON UPDATE CASCADE | SET NULL | SET DEFAULT
// kloska@users 20021112 - patch 1.7.2 - ON DELETE SET NULL | SET DEFAULT
// boucherb@users 20020310 - disable ALTER TABLE DDL on VIEWs (avoid NPE)
// fredt@users 20030314 - patch 1.7.2 by gilead@users - drop table if exists syntax
// boucherb@users 20030425 - DDL methods are moved to DatabaseCommandInterpreter.java
// boucherb@users 20030425 - refactoring DDL methods into smaller units
// fredt@users 20030609 - support for ALTER COLUMN SET/DROP DEFAULT / RENAME TO
// wondersonic@users 20031205 - IF EXISTS support for DROP INDEX
// fredt@users 20031224 - support for CREATE SEQUENCE ...
// fredt@users 20041209 - patch by tytar@users to set default table type
class DatabaseCommandInterpreter {

    private Tokenizer tokenizer = new Tokenizer();
    private Database  database;
    private Session   session;

    /**
     * Constructs a new DatabaseCommandInterpreter for the given Session
     *
     * @param s session
     */
    DatabaseCommandInterpreter(Session s) {
        session  = s;
        database = s.getDatabase();
    }

    /**
     * Executes the SQL String. This method is always called from a block
     * synchronized on the database object.
     *
     * @param sql query
     * @return the result of executing the given SQL String
     */
    Result execute(String sql) {

        Result result;
        String token;
        int    cmd;

        JavaSystem.gc();

        result = null;
        cmd    = Token.UNKNOWNTOKEN;

        try {
            tokenizer.reset(sql);

            while (true) {
                tokenizer.setPartMarker();
                session.setScripting(false);

                token = tokenizer.getSimpleToken();

                if (token.length() == 0) {
                    session.endSchemaDefinition();

                    break;
                }

                cmd = Token.get(token);

                if (cmd == Token.SEMICOLON) {
                    session.endSchemaDefinition();

                    continue;
                }

                result = executePart(cmd, token);

                if (result.mode == ResultConstants.ERROR) {
                    session.endSchemaDefinition();

                    break;
                }

                if (session.getScripting()) {
                    database.logger.writeToLog(session,
                                               tokenizer.getLastPart());
                }
            }
        } catch (Throwable t) {
            try {
                session.endSchemaDefinition();
            } catch (HsqlException e) {}

            result = new Result(t, tokenizer.getLastPart());
        }

        return result == null ? Session.emptyUpdateCount
                              : result;
    }

    private Result executePart(int cmd, String token) throws Throwable {

        Result result   = Session.emptyUpdateCount;
        int    brackets = 0;

        if (session.isSchemaDefintion()) {
            switch (cmd) {

                case Token.CREATE :
                case Token.GRANT :
                    break;

                default :
                    String schema = session.getSchemaName(null);

                    session.endSchemaDefinition();
                    database.schemaManager.dropSchema(schema, true);

                    throw Trace.error(Trace.INVALID_IDENTIFIER,
                                      Trace.IN_SCHEMA_DEFINITION,
                                      new Object[]{ token });
            }
        }

        switch (cmd) {

            case Token.OPENBRACKET : {
                brackets = Parser.parseOpenBrackets(tokenizer) + 1;

                tokenizer.getThis(Token.T_SELECT);
            }
            case Token.SELECT : {
                Parser parser = new Parser(session, database, tokenizer);
                CompiledStatement cStatement =
                    parser.compileSelectStatement(brackets);

                if (cStatement.parameters.length != 0) {
                    Trace.doAssert(
                        false,
                        Trace.getMessage(
                            Trace.ASSERT_DIRECT_EXEC_WITH_PARAM));
                }

                result = session.sqlExecuteCompiledNoPreChecks(cStatement);

                break;
            }
            case Token.INSERT : {
                Parser parser = new Parser(session, database, tokenizer);
                CompiledStatement cStatement =
                    parser.compileInsertStatement();

                if (cStatement.parameters.length != 0) {
                    Trace.doAssert(
                        false,
                        Trace.getMessage(
                            Trace.ASSERT_DIRECT_EXEC_WITH_PARAM));
                }

                result = session.sqlExecuteCompiledNoPreChecks(cStatement);

                break;
            }
            case Token.UPDATE : {
                Parser parser = new Parser(session, database, tokenizer);
                CompiledStatement cStatement =
                    parser.compileUpdateStatement();

                if (cStatement.parameters.length != 0) {
                    Trace.doAssert(
                        false,
                        Trace.getMessage(
                            Trace.ASSERT_DIRECT_EXEC_WITH_PARAM));
                }

                result = session.sqlExecuteCompiledNoPreChecks(cStatement);

                break;
            }
            case Token.DELETE : {
                Parser parser = new Parser(session, database, tokenizer);
                CompiledStatement cStatement =
                    parser.compileDeleteStatement();

                if (cStatement.parameters.length != 0) {
                    Trace.doAssert(
                        false,
                        Trace.getMessage(
                            Trace.ASSERT_DIRECT_EXEC_WITH_PARAM));
                }

                result = session.sqlExecuteCompiledNoPreChecks(cStatement);

                break;
            }
            case Token.CALL : {
                Parser parser = new Parser(session, database, tokenizer);
                CompiledStatement cStatement = parser.compileCallStatement();

                if (cStatement.parameters.length != 0) {
                    Trace.doAssert(
                        false,
                        Trace.getMessage(
                            Trace.ASSERT_DIRECT_EXEC_WITH_PARAM));
                }

                result = session.sqlExecuteCompiledNoPreChecks(cStatement);

                break;
            }
            case Token.SET :
                processSet();
                break;

            case Token.COMMIT :
                processCommit();
                break;

            case Token.ROLLBACK :
                processRollback();
                break;

            case Token.SAVEPOINT :
                processSavepoint();
                break;

            case Token.CREATE :
                processCreate();
                database.setMetaDirty(true);
                break;

            case Token.ALTER :
                processAlter();
                database.setMetaDirty(true);
                break;

            case Token.DROP :
                processDrop();
                database.setMetaDirty(true);
                break;

            case Token.GRANT :
                processGrantOrRevoke(true);
                database.setMetaDirty(false);
                break;

            case Token.REVOKE :
                processGrantOrRevoke(false);
                database.setMetaDirty(true);
                break;

            case Token.CONNECT :
                processConnect();
                database.setMetaDirty(false);
                session.setScripting(false);
                break;

            case Token.DISCONNECT :
                processDisconnect();
                session.setScripting(true);
                break;

            case Token.SCRIPT :
                result = processScript();
                break;

            case Token.SHUTDOWN :
                processShutdown();
                break;

            case Token.CHECKPOINT :
                processCheckpoint();
                break;

            case Token.EXPLAIN :
                result = processExplainPlan();
                break;

            case Token.RELEASE :
                processReleaseSavepoint();
                break;

            default :
                throw Trace.error(Trace.UNEXPECTED_TOKEN, token);
        }

        return result;
    }

    /**
     * Responsible for parsing and executing the SCRIPT SQL statement
     *
     * @return either an empty result or one in which each row is a DDL or DML
     * @throws IOException
     * @throws HsqlException
     */
    private Result processScript() throws IOException, HsqlException {

        String           token = tokenizer.getString();
        ScriptWriterText dsw   = null;

        session.checkAdmin();

        try {
            if (tokenizer.wasValue()) {
                if (tokenizer.getType() != Types.VARCHAR) {
                    throw Trace.error(Trace.INVALID_IDENTIFIER);
                }

                dsw = new ScriptWriterText(database, token, true, true, true);

                dsw.writeAll();

                return new Result(ResultConstants.UPDATECOUNT);
            } else {
                tokenizer.back();

                return DatabaseScript.getScript(database, false);
            }
        } finally {
            if (dsw != null) {
                dsw.close();
            }