Top Description Fields Constructors Methods
org.apache.derby.impl.store.raw.log

public Class ChecksumOperation

extends Object
implements Loggable
Class Inheritance
All Implemented Interfaces
org.apache.derby.iapi.store.raw.Loggable, org.apache.derby.iapi.services.io.Formatable, org.apache.derby.iapi.services.io.TypedFormat, java.io.Externalizable, java.io.Serializable
Imports
org.apache.derby.shared.common.sanity.SanityManager, org.apache.derby.iapi.services.io.Formatable, .FormatIdUtil, .StoredFormatIds, .CompressedNumber, .LimitObjectInput, org.apache.derby.catalog.UUID, org.apache.derby.iapi.store.raw.Transaction, .Loggable, org.apache.derby.iapi.store.raw.log.LogInstant, .LogFactory, org.apache.derby.iapi.store.raw.xact.RawTransaction, org.apache.derby.shared.common.error.StandardException, org.apache.derby.iapi.util.ByteArray, java.io.Externalizable, .OutputStream, .InputStream, .ObjectInput, .ObjectOutput, .IOException, java.util.zip.Checksum, .CRC32
A Log Operation that represents a checksum for a group of log records that are written to the tranaction log file. 




See Also

Loggable






Field Summary




Modifier and TypeField and Description

private Checksum
checksum




private byte
checksumAlgo




private long
checksumValue




public static final byte
CRC32_ALGORITHM




private int
dataLength




private static final int
formatLength










Constructor Summary




AccessConstructor and Description

public
ChecksumOperation()










Method Summary




Modifier and TypeMethod and Description

public void
doMe(Transaction 
the Transaction
xact, LogInstant 
the log instant of this operation
instant, LimitObjectInput 
optional data
in)
Implements org.apache.derby.iapi.store.raw.Loggable.doMe.


Nothing to do for the checksum log record because it does need to be
	  applied during redo.



protected int
getDataLength()
Access attributes of the checksum log record



public ByteArray
getPreparedLog()
Implements org.apache.derby.iapi.store.raw.Loggable.getPreparedLog.


the default for prepared log is always null for all the operations
that don't have optionalData.



public int
getStoredSize()




public int
getTypeFormatId()
Implements org.apache.derby.iapi.services.io.TypedFormat.getTypeFormatId.


Return my format identifier.



public int
group()
Implements org.apache.derby.iapi.store.raw.Loggable.group.


Checksum is a raw store operation



public void
init()




private void
initializeChecksumAlgo()




protected boolean
isChecksumValid(byte[] data, int off, int length)




public boolean
needsRedo(Transaction 
The transaction trying to redo this operation
xact)
Implements org.apache.derby.iapi.store.raw.Loggable.needsRedo.


Checksum does not need to be redone, it is used to just verify that
			log records are written completely.



public void
readExternal(ObjectInput 
the stream to read data from in order to restore the object
in)
Implements java.io.Externalizable.readExternal.


The object implements the readExternal method to restore its
contents by calling the methods of DataInput for primitive
types and readObject for objects, strings and arrays.



public void
releaseResource(Transaction xact)
Implements org.apache.derby.iapi.store.raw.Loggable.releaseResource.


Checksum has no resources to release



protected void
reset()




public String
toString()
Overrides java.lang.Object.toString.


DEBUG: Print self.



protected void
update(byte[] buf, int off, int len)




public void
writeExternal(ObjectOutput 
the stream to write the object to
out)
Implements java.io.Externalizable.writeExternal.


The object implements the writeExternal method to save its contents
by calling the methods of DataOutput for its primitive values or
calling the writeObject method of ObjectOutput for objects, strings,
and arrays.







Inherited from java.lang.Object:


cloneequalsfinalizegetClasshashCodenotifynotifyAllwaitwaitwait







Field Detail




checksumback to summary

private Checksum checksum






checksumAlgoback to summary

private byte checksumAlgo






checksumValueback to summary

private long checksumValue






CRC32_ALGORITHMback to summary

public static final byte CRC32_ALGORITHM






dataLengthback to summary

private int dataLength






formatLengthback to summary

private static final int formatLength








Constructor Detail




ChecksumOperationback to summary

public ChecksumOperation()








Method Detail




doMeback to summary

public void doMe(Transaction xact, LogInstant instant, LimitObjectInput in) throws StandardException
Implements org.apache.derby.iapi.store.raw.Loggable.doMe.

Nothing to do for the checksum log record because it does need to be
	  applied during redo.



Parameters



xact:Transaction
Doc from org.apache.derby.iapi.store.raw.Loggable.doMe.

the Transaction

instant:LogInstant
Doc from org.apache.derby.iapi.store.raw.Loggable.doMe.

the log instant of this operation

in:LimitObjectInput
Doc from org.apache.derby.iapi.store.raw.Loggable.doMe.

optional data



Exceptions



StandardException:
Doc from org.apache.derby.iapi.store.raw.Loggable.doMe.
Standard Derby policy.










getDataLengthback to summary

protected int getDataLength()
Access attributes of the checksum log record






getPreparedLogback to summary

public ByteArray getPreparedLog()
Implements org.apache.derby.iapi.store.raw.Loggable.getPreparedLog.

the default for prepared log is always null for all the operations
that don't have optionalData.  If an operation has optional data,
the operation need to prepare the optional data for this method.

Checksum has no optional data to write out






getStoredSizeback to summary

public int getStoredSize()






getTypeFormatIdback to summary

public int getTypeFormatId()
Implements org.apache.derby.iapi.services.io.TypedFormat.getTypeFormatId.

Return my format identifier.



Returns:int
Doc from org.apache.derby.iapi.services.io.TypedFormat.getTypeFormatId.

The identifier. (A UUID stuffed in an array
of 16 bytes).








groupback to summary

public int group()
Implements org.apache.derby.iapi.store.raw.Loggable.group.

Checksum is a raw store operation






initback to summary

public void init()






initializeChecksumAlgoback to summary

private void initializeChecksumAlgo()






isChecksumValidback to summary

protected boolean isChecksumValid(byte[] data, int off, int length)






needsRedoback to summary

public boolean needsRedo(Transaction xact)
Implements org.apache.derby.iapi.store.raw.Loggable.needsRedo.

Checksum does not need to be redone, it is used to just verify that
			log records are written completely.



Parameters



xact:Transaction
Doc from org.apache.derby.iapi.store.raw.Loggable.needsRedo.

The transaction trying to redo this operation



Returns:boolean
Doc from org.apache.derby.iapi.store.raw.Loggable.needsRedo.

true if operation needs redoing, false if not.








readExternalback to summary

public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
Implements java.io.Externalizable.readExternal.

Doc from java.io.Externalizable.readExternal.

The object implements the readExternal method to restore its
contents by calling the methods of DataInput for primitive
types and readObject for objects, strings and arrays.  The
readExternal method must read the values in the same sequence
and with the same types as were written by writeExternal.



Parameters



in:ObjectInput
the stream to read data from in order to restore the object



Exceptions



IOException:
if I/O errors occur

ClassNotFoundException:
If the class for an object being restored cannot be found.










releaseResourceback to summary

public void releaseResource(Transaction xact)
Implements org.apache.derby.iapi.store.raw.Loggable.releaseResource.

Checksum has no resources to release






resetback to summary

protected void reset()






toStringback to summary

public String toString()
Overrides java.lang.Object.toString.

DEBUG: Print self.



Returns:String
Doc from java.lang.Object.toString.

a string representation of the object








updateback to summary

protected void update(byte[] buf, int off, int len)






writeExternalback to summary

public void writeExternal(ObjectOutput out) throws IOException
Implements java.io.Externalizable.writeExternal.

Doc from java.io.Externalizable.writeExternal.

The object implements the writeExternal method to save its contents
by calling the methods of DataOutput for its primitive values or
calling the writeObject method of ObjectOutput for objects, strings,
and arrays.



Parameters



out:ObjectOutput
the stream to write the object to



Exceptions



IOException:
Includes any I/O exceptions that may occur