org.hsqldb.scriptio
Class ScriptWriterBase

java.lang.Object
  org.hsqldb.scriptio.ScriptWriterBase

Direct Known Subclasses:

ScriptWriterText

public abstract class ScriptWriterBase

extends Object

Handles all logging to file operations. A log consists of three blocks:

DDL BLOCK: definition of DB objects, users and rights at startup time
DATA BLOCK: all data for MEMORY tables at startup time
LOG BLOCK: SQL statements logged since startup or the last CHECKPOINT
The implementation of this class and its subclasses support the formats used for writing the data. In versions up to 1.7.2, this data is written to the *.script file for the database. Since 1.7.2 the data can also be written as binray in order to speed up shutdown and startup.

In 1.7.2, two separate files are used, one for the DDL + DATA BLOCK and the other for the LOG BLOCK.

A related use for this class is for saving a current snapshot of the database data to a user-defined file. This happens in the SHUTDOWN COMPACT process or done as a result of the SCRIPT command. In this case, the DATA block contains the CACHED table data as well.

DatabaseScriptReader and its subclasses read back the data at startup time.

Since:

1.7.2

Version:

1.7.2

Author:

fredt@users

Field Summary

static String[]	LIST_SCRIPT_FORMATS
static int	SCRIPT_BINARY_172
static int	SCRIPT_TEXT_170
static int	SCRIPT_ZIPPED_BINARY_172

Method Summary

void	close()
protected void	finishStream() This is not really useful in the current usage but may be if this class is used in a different way.
protected abstract void	initBuffers()
static ScriptWriterBase	newScriptWriter(Database db, String file, boolean includeCachedData, boolean newFile, int scriptType)
protected void	openFile() File is opened in append mode although in current usage the file never pre-exists
void	setWriteDelay(int delay) Not used in current implementation.
long	size()
void	sync() Called externally in write delay intervals.
void	writeAll()
protected abstract void	writeDataTerm()
protected void	writeDDL()
protected void	writeExistingData()
protected abstract void	writeSessionId(int sid)
protected void	writeSingleColumnResult(Result r)
protected void	writeTableInit(Table t)
protected void	writeTableTerm(Table t)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LIST_SCRIPT_FORMATS

public static String[] LIST_SCRIPT_FORMATS

SCRIPT_TEXT_170

public static final int SCRIPT_TEXT_170

See Also:

Constant Field Values

SCRIPT_BINARY_172

public static final int SCRIPT_BINARY_172

See Also:

Constant Field Values

SCRIPT_ZIPPED_BINARY_172

public static final int SCRIPT_ZIPPED_BINARY_172

See Also:

Constant Field Values

Method Detail

newScriptWriter

public static ScriptWriterBase newScriptWriter(Database db,
                                               String file,
                                               boolean includeCachedData,
                                               boolean newFile,
                                               int scriptType)
                                        throws HsqlException

Throws:

HsqlException

initBuffers

protected abstract void initBuffers()

setWriteDelay

public void setWriteDelay(int delay)

Not used in current implementation.

sync

public void sync()

Called externally in write delay intervals.

close

public void close()
           throws HsqlException

Throws:

HsqlException

size

public long size()

writeAll

public void writeAll()
              throws HsqlException

Throws:

HsqlException

openFile

protected void openFile()
                 throws HsqlException

File is opened in append mode although in current usage the file never pre-exists

Throws:

HsqlException

finishStream

protected void finishStream()
                     throws IOException

This is not really useful in the current usage but may be if this class is used in a different way.

Throws:

IOException

writeDDL

protected void writeDDL()
                 throws IOException,
                        HsqlException

Throws:

IOException

HsqlException

writeExistingData

protected void writeExistingData()
                          throws HsqlException,
                                 IOException

Throws:

HsqlException

IOException

writeTableInit

protected void writeTableInit(Table t)
                       throws HsqlException,
                              IOException

Throws:

HsqlException

IOException

writeTableTerm

protected void writeTableTerm(Table t)
                       throws HsqlException,
                              IOException

Throws:

HsqlException

IOException

writeSingleColumnResult

protected void writeSingleColumnResult(Result r)
                                throws HsqlException,
                                       IOException

Throws:

HsqlException

IOException

writeDataTerm

protected abstract void writeDataTerm()
                               throws IOException

Throws:

IOException

writeSessionId

protected abstract void writeSessionId(int sid)
                                throws IOException

Throws:

IOException