org.apache.hadoop.fs.s3a.impl

Class ExecutingStoreOperation<T>

java.lang.Object

org.apache.hadoop.fs.s3a.impl.AbstractStoreOperation

org.apache.hadoop.fs.s3a.impl.ExecutingStoreOperation<T>

Type Parameters:

T - return type of executed operation.

All Implemented Interfaces:

org.apache.hadoop.util.functional.CallableRaisingIOE<T>

Direct Known Subclasses:

CopyFromLocalOperation, DeleteOperation, GetContentSummaryOperation, MkdirOperation, RenameOperation

public abstract class ExecutingStoreOperation<T>
extends AbstractStoreOperation
implements org.apache.hadoop.util.functional.CallableRaisingIOE<T>

A subclass of AbstractStoreOperation which provides a method execute() that may be invoked exactly once. It declares itself a CallableRaisingIOE and can be handed straight to methods which take those as parameters.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ExecutingStoreOperation(StoreContext storeContext) Constructor.
protected	ExecutingStoreOperation(StoreContext storeContext, org.apache.hadoop.fs.store.audit.AuditSpan auditSpan) Constructor.

Method Summary

Modifier and Type	Method and Description
T	apply() Apply calls execute().
abstract T	execute() Execute the operation.
protected void	executeOnlyOnce() Check that the operation has not been invoked twice.

Methods inherited from class org.apache.hadoop.fs.s3a.impl.AbstractStoreOperation

activateAuditSpan, getAuditSpan, getStoreContext

Methods inherited from class java.lang.Object

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

Constructor Detail

ExecutingStoreOperation

protected ExecutingStoreOperation(StoreContext storeContext)

Constructor. Picks up the active audit span from the store context and stores it for later.

Parameters:

storeContext - store context.

ExecutingStoreOperation

protected ExecutingStoreOperation(StoreContext storeContext,
                                  org.apache.hadoop.fs.store.audit.AuditSpan auditSpan)

Constructor.

Parameters:

storeContext - store context.

auditSpan - active span

Method Detail

apply

public final T apply()
              throws IOException

Apply calls execute().

Specified by:

apply in interface org.apache.hadoop.util.functional.CallableRaisingIOE<T>

Returns:

the result.

Throws:

IOException - IO problem

execute

public abstract T execute()
                   throws IOException

Execute the operation. Subclasses MUST call executeOnlyOnce() so as to force the (atomic) re-entrancy check.

Returns:

the result.

Throws:

IOException - IO problem

executeOnlyOnce

protected void executeOnlyOnce()

Check that the operation has not been invoked twice. This is an atomic check. After the check: activates the span.

Throws:

IllegalStateException - on a second invocation.