com.facebook.presto.memory.context

Class SimpleLocalMemoryContext

java.lang.Object

com.facebook.presto.memory.context.SimpleLocalMemoryContext

All Implemented Interfaces:

LocalMemoryContext

@ThreadSafe
public final class SimpleLocalMemoryContext
extends Object
implements LocalMemoryContext

Constructor Summary

Constructors

Constructor and Description
SimpleLocalMemoryContext(AggregatedMemoryContext parentMemoryContext, String allocationTag)

Method Summary

Modifier and Type	Method and Description
void	close() Closes this LocalMemoryContext.
long	getBytes()
com.google.common.util.concurrent.ListenableFuture<?>	setBytes(long bytes) When this method returns, the bytes tracked by this LocalMemoryContext has been updated.
String	toString()
boolean	trySetBytes(long bytes) This method can return false when there is not enough memory available to satisfy a positive delta allocation (bytes is greater than the bytes tracked by this LocalMemoryContext).

Methods inherited from class java.lang.Object

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

Constructor Detail

SimpleLocalMemoryContext

public SimpleLocalMemoryContext(AggregatedMemoryContext parentMemoryContext,
                                String allocationTag)

Method Detail

getBytes

public long getBytes()

Specified by:

getBytes in interface LocalMemoryContext

setBytes

public com.google.common.util.concurrent.ListenableFuture<?> setBytes(long bytes)

Description copied from interface: LocalMemoryContext

When this method returns, the bytes tracked by this LocalMemoryContext has been updated. The returned future will tell the caller whether it should block before reserving more memory (which happens when the memory pools are low on memory).

Note: Canceling the returned future will complete it immediately even though the memory pools are low on memory, and callers blocked on this future will proceed to allocating more memory from the exhausted pools, which will violate the protocol of Presto MemoryPool implementation.

Specified by:

setBytes in interface LocalMemoryContext

trySetBytes

public boolean trySetBytes(long bytes)

Description copied from interface: LocalMemoryContext

This method can return false when there is not enough memory available to satisfy a positive delta allocation (bytes is greater than the bytes tracked by this LocalMemoryContext).

Specified by:

trySetBytes in interface LocalMemoryContext

Returns:

true if the bytes tracked by this LocalMemoryContext can be set to bytes.

close

public void close()

Description copied from interface: LocalMemoryContext

Closes this LocalMemoryContext. Once closed the bytes tracked by this LocalMemoryContext will be set to 0, and none of its methods (except getBytes()) can be called.

Specified by:

close in interface LocalMemoryContext

toString

public String toString()

Overrides:

toString in class Object