jdbcstatement.java

非常棒的java数据库

/*
 * Copyright 2004-2008 H2 Group. Licensed under the H2 License, Version 1.0
 * (http://h2database.com/html/license.html).
 * Initial Developer: H2 Group
 */
package org.h2.jdbc;


import java.sql.BatchUpdateException;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.SQLWarning;
import java.sql.Statement;

import org.h2.command.CommandInterface;
import org.h2.constant.ErrorCode;
import org.h2.constant.SysProperties;
import org.h2.engine.SessionInterface;
import org.h2.message.Message;
import org.h2.message.TraceObject;
import org.h2.result.ResultInterface;
import org.h2.util.ObjectArray;

/**
 * Represents a statement.
 */
public class JdbcStatement extends TraceObject implements Statement {

    protected JdbcConnection conn;
    protected SessionInterface session;
    protected JdbcResultSet resultSet;
    protected int maxRows;
    protected boolean escapeProcessing = true;
    protected int fetchSize = SysProperties.SERVER_RESULT_SET_FETCH_SIZE;
    protected int updateCount;
    private CommandInterface executingCommand;
    private ObjectArray batchCommands;
    protected int resultSetType;
    protected boolean closedByResultSet;

    /**
     * Executes a query (select statement) and returns the result set.
     * If another result set exists for this statement, this will be closed
     * (even if this statement fails).
     *
     * @return the result set
     */
    public ResultSet executeQuery(String sql) throws SQLException {
        try {
            int id = getNextId(TraceObject.RESULT_SET);
            if (debug()) {
                debugCodeAssign("ResultSet", TraceObject.RESULT_SET, id, "executeQuery(" + quote(sql) + ")");
            }
            checkClosed();
            closeOld();
            if (escapeProcessing) {
                sql = conn.translateSQL(sql);
            }
            synchronized (session) {
                CommandInterface command = conn.prepareCommand(sql, fetchSize);
                ResultInterface result;
                boolean scrollable = resultSetType != ResultSet.TYPE_FORWARD_ONLY;
                setExecutingStatement(command);
                try {
                    result = command.executeQuery(maxRows, scrollable);
                } finally {
                    setExecutingStatement(null);
                }
                command.close();
                resultSet = new JdbcResultSet(session, conn, this, result, id, closedByResultSet, scrollable);
            }
            return resultSet;
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Executes a statement (insert, update, delete, create, drop)
     * and returns the update count.
     * If another result set exists for this statement, this will be closed
     * (even if this statement fails).
     *
     * If the statement is a create or drop and does not throw an exception,
     * the current transaction (if any) is committed after executing the statement.
     * If auto commit is on, this statement will be committed.
     *
     * @param sql the SQL statement
     * @return the update count (number of row affected by an insert,
     *         update or delete, or 0 if no rows or the statement was a
     *         create, drop, commit or rollback)
     * @throws SQLException if a database error occurred or a
     *         select statement was executed
     */
    public int executeUpdate(String sql) throws SQLException {
        try {
            debugCodeCall("executeUpdate", sql);
            checkClosed();
            closeOld();
            if (escapeProcessing) {
                sql = conn.translateSQL(sql);
            }
            CommandInterface command = conn.prepareCommand(sql, fetchSize);
            synchronized (session) {
                setExecutingStatement(command);
                try {
                    updateCount = command.executeUpdate();
                } finally {
                    setExecutingStatement(null);
                }
            }
            command.close();
            return updateCount;
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Executes an arbitrary statement. If another result set exists for this
     * statement, this will be closed (even if this statement fails).
     * 
     * If the statement is a create or drop and does not throw an exception, the
     * current transaction (if any) is committed after executing the statement.
     * If auto commit is on, and the statement is not a select, this statement
     * will be committed.
     * 
     * @return true if a result set is available, false if not
     */
    public boolean execute(String sql) throws SQLException {
        try {
            int id = getNextId(TraceObject.RESULT_SET);
            if (debug()) {
                debugCodeCall("execute", sql);
            }
            checkClosed();
            closeOld();
            if (escapeProcessing) {
                sql = conn.translateSQL(sql);
            }
            CommandInterface command = conn.prepareCommand(sql, fetchSize);
            boolean returnsResultSet;
            synchronized (session) {
                setExecutingStatement(command);
                try {
                    if (command.isQuery()) {
                        returnsResultSet = true;
                        boolean scrollable = resultSetType != ResultSet.TYPE_FORWARD_ONLY;
                        ResultInterface result = command.executeQuery(maxRows, scrollable);
                        resultSet = new JdbcResultSet(session, conn, this, result, id, closedByResultSet, scrollable);
                    } else {
                        returnsResultSet = false;
                        updateCount = command.executeUpdate();
                    }
                } finally {
                    setExecutingStatement(null);
                }
            }
            command.close();
            return returnsResultSet;
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Returns the last result set produces by this statement.
     *
     * @return the result set
     */
    public ResultSet getResultSet() throws SQLException {
        try {
            checkClosed();
            if (resultSet != null) {
                int id = resultSet.getTraceId();
                debugCodeAssign("ResultSet", TraceObject.RESULT_SET, id, "getResultSet()");
            } else {
                debugCodeCall("getResultSet");
            }
            return resultSet;
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Returns the last update count of this statement.
     *
     * @return the update count (number of row affected by an insert,
     *         update or delete, or 0 if no rows or the statement was a
     *         create, drop, commit or rollback; -1 if the statement was a select).
     * @throws SQLException if this object is closed or invalid
     */
    public int getUpdateCount() throws SQLException {
        try {
            debugCodeCall("getUpdateCount");
            checkClosed();
            return updateCount;
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Closes this statement.
     * All result sets that where created by this statement
     * become invalid after calling this method.
     */
    public void close() throws SQLException {
        try {
            debugCodeCall("close");
            closeOld();
            if (conn != null) {
                conn = null;
            }
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Returns the connection that created this object.
     *
     * @return the connection
     */
    public Connection getConnection() throws SQLException {
        try {
            debugCodeCall("getConnection");
            checkClosed();
            return conn;
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Gets the first warning reported by calls on this object.
     * This driver does not support warnings, and will always return null.
     *
     * @return null
     */
    public SQLWarning getWarnings() throws SQLException {
        try {
            debugCodeCall("getWarnings");
            checkClosed();
            return null;
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Clears all warnings. As this driver does not support warnings,
     * this call is ignored.
     */
    public void clearWarnings() throws SQLException {
        try {
            debugCodeCall("clearWarnings");
            checkClosed();
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Moves to the next result set - however there is always only one result
     * set. This call also closes the current result set (if there is one).
     * Returns true if there is a next result set (that means - it always
     * returns false).
     * 
     * @return false
     * @throws SQLException if this object is closed.
     */
    public boolean getMoreResults() throws SQLException {
        try {
            debugCodeCall("getMoreResults");
            checkClosed();
            closeOld();
            return false;
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Sets the name of the cursor. This call is ignored.
     *
     * @param name ignored
     * @throws SQLException if this object is closed
     */
    public void setCursorName(String name) throws SQLException {
        try {
            debugCodeCall("setCursorName", name);
            checkClosed();
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Sets the fetch direction.
     * This call is ignored by this driver.
     *
     * @param direction ignored
     * @throws SQLException if this object is closed
     */
    public void setFetchDirection(int direction) throws SQLException {
        try {
            debugCodeCall("setFetchDirection", direction);
            checkClosed();
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

   /**
     * Gets the fetch direction.
     *
     * @return FETCH_FORWARD
     * @throws SQLException if this object is closed
     */
    public int getFetchDirection() throws SQLException {
        try {
            debugCodeCall("getFetchDirection");
            checkClosed();
            return ResultSet.FETCH_FORWARD;
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Gets the maximum number of rows for a ResultSet.
     *
     * @return the number of rows where 0 means no limit
     * @throws SQLException if this object is closed
     */
    public int getMaxRows() throws SQLException {
        try {
            debugCodeCall("getMaxRows");
            checkClosed();
            return maxRows;
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Gets the maximum number of rows for a ResultSet.
     *
     * @param maxRows the number of rows where 0 means no limit
     * @throws SQLException if this object is closed
     */
    public void setMaxRows(int maxRows) throws SQLException {
        try {
            debugCodeCall("setMaxRows", maxRows);
            checkClosed();
            if (maxRows < 0) {
                throw Message.getInvalidValueException(""+maxRows, "maxRows");
            }
            this.maxRows = maxRows;
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Sets the number of rows suggested to read in one step.
     * This value cannot be higher than the maximum rows (setMaxRows)
     * set by the statement or prepared statement, otherwise an exception
     * is throws. Setting the value to 0 will set the default value.
     * The default value can be changed using the system property
     * h2.serverResultSetFetchSize.
     *
     * @param rows the number of rows
     * @throws SQLException if this object is closed
     */
    public void setFetchSize(int rows) throws SQLException {
        try {
            debugCodeCall("setFetchSize", rows);
            checkClosed();
            if (rows < 0 || (rows > 0 && maxRows > 0 && rows > maxRows)) {
                throw Message.getInvalidValueException("" + rows, "rows");
            }
            if (rows == 0) {
                rows = SysProperties.SERVER_RESULT_SET_FETCH_SIZE;
            }
            fetchSize = rows;
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Gets the number of rows suggested to read in one step.
     *
     * @return the current fetch size
     * @throws SQLException if this object is closed
     */
    public int getFetchSize() throws SQLException {
        try {
            debugCodeCall("getFetchSize");
            checkClosed();
            return fetchSize;
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Gets the result set concurrency created by this object.
     *
     * @return ResultSet.CONCUR_UPDATABLE
     * @throws SQLException if this object is closed
     */
    public int getResultSetConcurrency() throws SQLException {
        try {
            debugCodeCall("getResultSetConcurrency");
            checkClosed();
            return ResultSet.CONCUR_UPDATABLE;
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Gets the result set type.
     *
     * @return the type
     * @throws SQLException if this object is closed
     */
    public int getResultSetType()  throws SQLException {
        try {
            debugCodeCall("getResultSetType");
            checkClosed();
            return resultSetType;
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }

    /**
     * Gets the maximum number of bytes for a result set column.
     *
     * @return always 0 for no limit
     * @throws SQLException if this object is closed
     */
    public int getMaxFieldSize() throws SQLException {
        try {
            debugCodeCall("getMaxFieldSize");
            checkClosed();
            return 0;
        } catch (Throwable e) {
            throw logAndConvert(e);
        }
    }