org.neo4j.kernel.impl.index
Class IndexCommand

java.lang.Object
  org.neo4j.kernel.impl.transaction.xaframework.XaCommand
      org.neo4j.kernel.impl.index.IndexCommand

Direct Known Subclasses:

IndexCommand.AddCommand, IndexCommand.AddRelationshipCommand, IndexCommand.CreateCommand, IndexCommand.DeleteCommand, IndexCommand.RemoveCommand

public abstract class IndexCommand
extends XaCommand

Created from IndexDefineCommand or read from a logical log. Contains all the different types of commands that an Index need to support.

Nested Class Summary

static class	IndexCommand.AddCommand
static class	IndexCommand.AddRelationshipCommand
static class	IndexCommand.CreateCommand
static class	IndexCommand.DeleteCommand
static class	IndexCommand.RemoveCommand

Field Summary

static byte	NODE
static byte	RELATIONSHIP

Method Summary

protected byte	endNodeNeedsLong()
boolean	equals(Object obj)
void	execute() Executes the command and makes it persistent.
long	getEntityId()
byte	getEntityType()
byte	getIndexNameId()
byte	getKeyId()
Object	getValue()
boolean	isConsideredNormalWriteCommand()
protected static byte	needsLong(long value)
protected static void	putIntOrLong(LogBuffer buffer, long id)
static XaCommand	readCommand(ReadableByteChannel channel, ByteBuffer buffer)
protected byte	startNodeNeedsLong()
protected void	writeHeader(LogBuffer buffer)
void	writeToFile(LogBuffer buffer) When a command is added to a transaction (usually when it is created) it must be written to the XaLogicalLog.

Methods inherited from class org.neo4j.kernel.impl.transaction.xaframework.XaCommand

isRecovered, rollback, setRecovered

Methods inherited from class java.lang.Object

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

Field Detail

NODE

public static final byte NODE

See Also:

Constant Field Values

RELATIONSHIP

public static final byte RELATIONSHIP

See Also:

Constant Field Values

Method Detail

getIndexNameId

public byte getIndexNameId()

getEntityType

public byte getEntityType()

getEntityId

public long getEntityId()

getKeyId

public byte getKeyId()

getValue

public Object getValue()

execute

public void execute()

Description copied from class: XaCommand

Executes the command and makes it persistent. This method must succeed, any protests about this command not being able to execute should be done before execution of any command within the transaction.

Specified by:

execute in class XaCommand

writeToFile

public void writeToFile(LogBuffer buffer)
                 throws IOException

Description copied from class: XaCommand

When a command is added to a transaction (usually when it is created) it must be written to the XaLogicalLog. This method should write all the data that is needed to re-create the command (see XaCommandFactory).

Write the data to the fileChannel, you can use the buffer supplied or create your own buffer since its capacity is very small (137 bytes or something). Acccess to writing commands is synchronized, only one command will be written at a time so if you need to write larger data sets the commands can share the same buffer.

Don't throw an IOException to imply something is wrong with the command. An exception should only be thrown here if there is a real IO failure. If something is wrong with this command it should have been detected when it was created.

Don't force, position or anything except normal forward write with the file channel.

Specified by:

writeToFile in class XaCommand

Parameters:

buffer - A small byte buffer that can be used to write command data

Throws:

IOException - In case of *real* IO failure

writeHeader

protected void writeHeader(LogBuffer buffer)
                    throws IOException

Throws:

IOException

putIntOrLong

protected static void putIntOrLong(LogBuffer buffer,
                                   long id)
                            throws IOException

Throws:

IOException

needsLong

protected static byte needsLong(long value)

startNodeNeedsLong

protected byte startNodeNeedsLong()

endNodeNeedsLong

protected byte endNodeNeedsLong()

isConsideredNormalWriteCommand

public boolean isConsideredNormalWriteCommand()

readCommand

public static XaCommand readCommand(ReadableByteChannel channel,
                                    ByteBuffer buffer)
                             throws IOException

Throws:

IOException

equals

public boolean equals(Object obj)

Overrides:

equals in class Object