org.omegahat.Environment.Interpreter
Class TaskQueueEvaluator

java.lang.Object
  |
  +--org.omegahat.Environment.Interpreter.BasicEvaluator
        |
        +--org.omegahat.Environment.Interpreter.UtilityEvaluator
              |
              +--org.omegahat.Environment.Interpreter.UserClassEvaluator
                    |
                    +--org.omegahat.Environment.Interpreter.TaskQueueEvaluator

All Implemented Interfaces:

DatabaseCustomer, Evaluator, ManagedEvaluatorInt, java.lang.Runnable, java.io.Serializable

public class TaskQueueEvaluator

extends UserClassEvaluator

implements java.lang.Runnable

An early and untested version of an evaluator that works by processing elements in its TaskQueue rather than being signalled using the InputConsumer listener mechanism as in the regular evaluator classes. Instead, other objects add Task objects to the queue and have these evaluated in the background. This will normally be used in a dedicated thread with other activities being carried on in other threads that communicate with this evaluator by inserting Tasks into its queue. This is very similar to the classes in TaskManager and DistributedTaskManager

See Also:

Serialized Form

Field Summary

protected TaskQueue	queue The queue to which new Tasks are added by other objects (potentially running in different threads) and which this evaluator monitors processing the tasks as it becomes idle and tasks are available.
protected boolean	terminate A flag used to allow another object to indicate that the evaluator should not process any more tasks on its queue.

Fields inherited from class org.omegahat.Environment.Interpreter.UserClassEvaluator

classManager

Fields inherited from class org.omegahat.Environment.Interpreter.BasicEvaluator

allowUnrestrictedAccess, class_lists, currentExpression, data, databases, debugger, DefaultAttachIndex, defaultDatabase, dynamicClassLoader, errorHandler, evaluationEvent, evaluationListeners, initialized, internalFunctionTables, internalPrimitiveClassNames, internalPrimitiveClassTable, lexer, localClasses, manager, options, output, parser, primitive_classes, primitiveClasses, PrimitiveClassNames, primitiveTypeNames, primitiveTypes, reversePrimitiveTypes, ShowMultipleClasses, sourceStack, stderr, stdout, SubEvaluationListeners, taskHistory, toplevelExpression, warningMessages

Fields inherited from interface org.omegahat.Environment.Interpreter.Evaluator

ThisVariableName

Constructor Summary

TaskQueueEvaluator()

TaskQueueEvaluator(Evaluator parent)

TaskQueueEvaluator(EvaluatorManager manager)

TaskQueueEvaluator(Options opts)

Method Summary

Task	addTask(ExpressionInt expression) Add an expression to the evaluator's task queue by constructing a new Task to contain it.
Task	addTask(Task task) Add a task to the queue.
void	run() This is the method that causes the evaluator to start processing the tasks on its queue or wait for new ones to be added.
boolean	terminate() Determine whether the evaluator should quit from processing any further tasks from the queue.
boolean	terminate(boolean val) Set the terminatation flag, signalling that the evaluator should not process any further tasks on its queue.

Methods inherited from class org.omegahat.Environment.Interpreter.UserClassEvaluator

addMethod, classManager, classManager, createInstance, createInstance, createInstance, defineClass, defineClass, defineClass, defineClass, defineClass, defineClass, DefineUserClass, DefineUserClass, DefineUserClass, findUserClass, findUserClass, parseClass, parser

Methods inherited from class org.omegahat.Environment.Interpreter.UtilityEvaluator

evaluator, exec, exec, findFile, getEvaluator, setProperty, setProperty

Methods inherited from class org.omegahat.Environment.Interpreter.BasicEvaluator

addEvaluationListener, addFunctionTable, addFunctionTable, addSourceInput, addToHistory, allowUnrestrictedAccess, allowUnrestrictedAccess, asObject, asObject, asObject, asObjectName, asPrimitiveClass, assign, assign, assign, asWriter, attach, attach, attach, attach, attach, attach, attach, classInit, classLists, classLists, classPath, classPath, commandLine, convertPrimitive, copy, copy, copyByConstructor, copyBySerialization, createClassLists, currentExpression, currentExpression, data, data, database, database, database, Debug, Debug, Debug, Debug, Debug, debugger, debugger, defaultDatabase, defaultDatabase, defaultDatabase, defaultErrorHandler, detach, detach, displayTask, displayTask, displayWarnings, displayWarnings, dynamicClassLoader, dynamicClassLoader, endSource, endSource, endSource, endTaskEvaluation, error, error, errorHandler, errorHandler, evaluate, evaluate, evaluate, evaluate, evaluationError, evaluationListeners, evaluationListeners, evaluationListeners, exists, exit, exit, expandClassName, expandedClassPathElement, find, findAsField, findClass, findClass, findClass, findClass, findFunction, findFunctionOrMethod, functionTableList, get, get, get, get, get, get, get, get, get, getBaseURL, getEvaluationEvent, getEvaluationListeners, getField, getSubEvaluationListeners, help, Import, Import, Import, init, initialize, initTaskEvaluation, internalFunctionTables, isPrimitive, isPrimitive, javaVersion, lexer, lexer, lexer, localClasses, localClasses, manager, manager, newDatabase, newDatabase, notifyListeners, notifyListeners, objects, objects, objects, options, options, output, output, output, parse, parse, parse, parse, primitiveClass, q, q, remove, remove, remove, removeFunctionTable, same, searchForClass, searchPath, searchPath, searchPath, searchPath, setEvaluationEvent, setEvaluationListeners, setSubEvaluationListeners, show, show, show, source, source, source, source, source, source, source, source, source, sourceStack, stderr, stderr, stdout, stdout, taskHistory, taskHistory, toplevelExpression, toplevelExpression, useLazyEvaluation, warning, warning, warning, warnings, warnings, where, which, which

Methods inherited from class java.lang.Object

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

Field Detail

queue

protected TaskQueue queue

The queue to which new Tasks are added by other objects (potentially running in different threads) and which this evaluator monitors processing the tasks as it becomes idle and tasks are available.

terminate

protected boolean terminate

A flag used to allow another object to indicate that the evaluator should not process any more tasks on its queue.

Constructor Detail

TaskQueueEvaluator

public TaskQueueEvaluator()

TaskQueueEvaluator

public TaskQueueEvaluator(Options opts)

TaskQueueEvaluator

public TaskQueueEvaluator(Evaluator parent)

TaskQueueEvaluator

public TaskQueueEvaluator(EvaluatorManager manager)

Method Detail

addTask

public Task addTask(Task task)

Add a task to the queue. This is synchronized so as to avoid concurrent access. For this reason, this should be used rather than adding the Task object directly to the TaskQueue obtained via taskQueue().

addTask

public Task addTask(ExpressionInt expression)

Add an expression to the evaluator's task queue by constructing a new Task to contain it.

run

public void run()

This is the method that causes the evaluator to start processing the tasks on its queue or wait for new ones to be added. This terminates only when the appropriate flag is raised using the terminate() method. This is the method that is run when the object is handed to a Thread.

Specified by:

run in interface java.lang.Runnable

Overrides:

run in class BasicEvaluator

Following copied from class: org.omegahat.Environment.Interpreter.BasicEvaluator

See Also:

TaskQueueEvaluator, TaskQueue

terminate

public boolean terminate()

Determine whether the evaluator should quit from processing any further tasks from the queue. This does not cause the currently active task to be interrupted.

terminate

public boolean terminate(boolean val)

Set the terminatation flag, signalling that the evaluator should not process any further tasks on its queue. It may leave these tasks to be evaluated later.