com.scalar.db.util.groupcommit

Class GroupCommitter<PARENT_KEY,CHILD_KEY,FULL_KEY,EMIT_PARENT_KEY,EMIT_FULL_KEY,V>

java.lang.Object

com.scalar.db.util.groupcommit.GroupCommitter<PARENT_KEY,CHILD_KEY,FULL_KEY,EMIT_PARENT_KEY,EMIT_FULL_KEY,V>

Type Parameters:

PARENT_KEY - A key type to NormalGroup which contains multiple slots and is group-committed.

CHILD_KEY - A key type to slot in NormalGroup which can contain a value ready to commit.

FULL_KEY - A key type to DelayedGroup which contains a single slot and is singly-committed.

EMIT_PARENT_KEY - A parent-key type that Emitter can interpret.

EMIT_FULL_KEY - A full-key type that Emitter can interpret.

V - A value type to be set to a slot.

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

Direct Known Subclasses:

CoordinatorGroupCommitter

@ThreadSafe
public class GroupCommitter<PARENT_KEY,CHILD_KEY,FULL_KEY,EMIT_PARENT_KEY,EMIT_FULL_KEY,V>
extends java.lang.Object
implements java.io.Closeable

A group committer which is responsible for the group and slot managements and emits ready groups. This class receives 4 generic types as keys. But it's likely only one or a few key types are enough. The reason to use the 4 keys is to detect wrong key usages at compile time.

Constructor Summary

Constructors

Constructor and Description
GroupCommitter(java.lang.String label, GroupCommitConfig config, GroupCommitKeyManipulator<PARENT_KEY,CHILD_KEY,FULL_KEY,EMIT_PARENT_KEY,EMIT_FULL_KEY> keyManipulator)

Method Summary

Modifier and Type	Method and Description
void	close() Closes the resources.
void	ready(FULL_KEY fullKey, V value) Marks the slot associated with the specified key READY and then, waits until the group which contains the slot is emitted.
void	remove(FULL_KEY fullKey) Removes the slot from the group.
FULL_KEY	reserve(CHILD_KEY childKey) Reserves a new slot in the current NormalGroup.
void	setEmitter(Emittable<EMIT_PARENT_KEY,EMIT_FULL_KEY,V> emitter) Set an emitter which contains implementation to emit values.

Methods inherited from class java.lang.Object

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

Constructor Detail

GroupCommitter

public GroupCommitter(java.lang.String label,
                      GroupCommitConfig config,
                      GroupCommitKeyManipulator<PARENT_KEY,CHILD_KEY,FULL_KEY,EMIT_PARENT_KEY,EMIT_FULL_KEY> keyManipulator)

Parameters:

label - A label used for thread name.

config - A configuration.

keyManipulator - A key manipulator that contains logics how to treat keys.

Method Detail

setEmitter

public void setEmitter(Emittable<EMIT_PARENT_KEY,EMIT_FULL_KEY,V> emitter)

Set an emitter which contains implementation to emit values. Ideally, this should be passed to the constructor, but the instantiation timings of GroupCommitter and Emittable can be different. That's why this API exists.

Parameters:

emitter - An emitter.

reserve

public FULL_KEY reserve(CHILD_KEY childKey)

Reserves a new slot in the current NormalGroup. The slot may be moved to a DelayedGroup later.

Parameters:

childKey - A child key.

Returns:

The full key associated with the reserved slot.

ready

public void ready(FULL_KEY fullKey,
                  V value)
           throws GroupCommitException

Marks the slot associated with the specified key READY and then, waits until the group which contains the slot is emitted.

Parameters:

fullKey - A full key associated with the slot already reserved with reserve(CHILD_KEY).

value - A value to be set to the slot. It will be committed with other values contained in slots of the same group.

Throws:

GroupCommitException - when group commit fails

remove

public void remove(FULL_KEY fullKey)

Removes the slot from the group. This method needs to be called if the group commit for the key is canceled and ready(FULL_KEY, V) won't be called for it.

Parameters:

fullKey - A full key to specify the slot.

close

public void close()

Closes the resources. The ExecutorServices are created as daemon, so calling this method isn't needed. But for testing, this should be called for resources.

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable