Package org.sentrysoftware.jawk.jrt

Class BlockObject

java.lang.Object

org.sentrysoftware.jawk.jrt.BlockObject

public abstract class BlockObject
extends Object

An item which blocks until something useful can be done with the object. The BlockManager multiplexes BlockObjects such that unblocking one BlockObject causes the BlockManager to dispatch the notifier tag result of the BlockObject.

BlockObjects are chained. The BlockManager blocks on all chained BlockObjects until one is unblocked.

Subclasses must provide meaningful block() and getNotifierTag() routines.

BlockObjects do not actually perform the client blocking. This is done by the BlockManager at the AVM (interpreted) or compiled runtime environment. The AVM/compiled environments make special provision to return the head block object to the BlockManager (within _EXTENSION_ keyword processing).

Author:

Danny Daglas

See Also:

• BlockManager

Method Summary

Modifier and Type	Method	Description
abstract void	block()	Block until meaningful data is made available for the client application.
final void	clearNextBlockObject()	Eliminate the rest of the BlockObject chain.
List<BlockObject>	getBlockObjects()	Obtain all chained BlockObjects as a List, including this one.
abstract String	getNotifierTag()	Construct a meaningful notifier tag for this BlockObject.
void	setNextBlockObject(BlockObject bo)	Chain this BlockObject to another BlockObject.
final String	toString()	Ensure non-evaluation of a BlockObject by throwing an AWK Runtime exception, in case it leaks into AWK evaluation space.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Details

getNotifierTag

public abstract String getNotifierTag()

Construct a meaningful notifier tag for this BlockObject.

Returns:

a String object

block

public abstract void block()
                    throws InterruptedException

Block until meaningful data is made available for the client application. This is called by the BlockManager in a way such that the BlockManager waits for one BlockObject to unblock.

Throws:

InterruptedException - if any.

clearNextBlockObject

public final void clearNextBlockObject()

Eliminate the rest of the BlockObject chain.

setNextBlockObject

public void setNextBlockObject(BlockObject bo)

Chain this BlockObject to another BlockObject. The chain is linear and there is no upper bounds on the number of BlockObjects that can be supported.

Parameters:

bo - a BlockObject object

getBlockObjects

public List<BlockObject> getBlockObjects()

Obtain all chained BlockObjects as a List, including this one. A BlockObject chain cycle causes a runtime exception to be thrown.

Returns:

A List of chained BlockObjects, including this one.

Throws:

AwkRuntimeException - if the BlockObject chain contains a cycle.

toString

public final String toString()

Ensure non-evaluation of a BlockObject by throwing an AWK Runtime exception, in case it leaks into AWK evaluation space.

Overrides:

toString in class Object