org.omegahat.Environment.Interpreter
Class SignallableEvaluator

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

All Implemented Interfaces:

DatabaseCustomer, Evaluator, ManagedEvaluatorInt, java.lang.Runnable, java.io.Serializable, kh.signal.SignalListener

Direct Known Subclasses:

UserLevelSignalHandler

public class SignallableEvaluator

extends UserClassEvaluator

implements kh.signal.SignalListener

This is a version of the evaluator that is capable of catching UNIX-style interrupts (Ctrl-C, for example). This can be used to conclude the evaluation of top-level tasks prematurely. This class has not been used extensively but could become necessary to interrupt long-running tasks. Alternatively, we can have another thread (or GUI button) that controls the (default) evaluator.

This uses JNI (Java Native Interface) code to implement the signal catching and so is not portable and requires a C-level library to be installed. Additionally, it requires a few additional Java classes to be in the classpath. That code is written by Kevin Hester.

See Also:

Serialized Form

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 kh.signal.SignalListener

SIG_MAX, SIG_MIN, SIGFPE, SIGHUP, SIGILL, SIGINT, SIGKILL, SIGQUIT, SIGTERM, SIGTRAP

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

ThisVariableName

Constructor Summary

SignallableEvaluator()

SignallableEvaluator(EvaluatorManager mgr)

SignallableEvaluator(Options opts)

Method Summary

boolean	isInterested(int signalNum)
boolean	registerForSignals() Register an interest in being informed about signals.
void	signalReceived(int signalNum) Method that is invoked by the signal administrator when it detects a signal has been raised.

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, run, 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

Constructor Detail

SignallableEvaluator

public SignallableEvaluator(Options opts)

SignallableEvaluator

public SignallableEvaluator()

SignallableEvaluator

public SignallableEvaluator(EvaluatorManager mgr)

Method Detail

signalReceived

public void signalReceived(int signalNum)

Method that is invoked by the signal administrator when it detects a signal has been raised. Here we could remove the top-level task and terminate evaluating any more of its sub-expressions.

Specified by:

signalReceived in interface kh.signal.SignalListener

Parameters:

signalNum - indicator of what type of signal was raised.

isInterested

public boolean isInterested(int signalNum)

Specified by:

isInterested in interface kh.signal.SignalListener

registerForSignals

public boolean registerForSignals()

Register an interest in being informed about signals.