com.declarativa.interprolog

Class SubprocessEngine

java.lang.Object

com.declarativa.interprolog.AbstractPrologEngine

com.declarativa.interprolog.SubprocessEngine

All Implemented Interfaces:

PrologEngine

Direct Known Subclasses:

GNUSubprocessEngine, RemoteXSBSubprocessEngine, SWISubprocessEngine, XSBSubprocessEngine, YAPSubprocessEngine

public abstract class SubprocessEngine
extends AbstractPrologEngine

A PrologEngine implemented over TCP/IP sockets. A SubprocessEngine object represents and gives access to a running Prolog process in background. Multiple instances correspond to multiple Prolog processes, outside the Java Virtual Machine.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SubprocessEngine.OutputDumper Useful for testing

Field Summary

Fields

Modifier and Type	Field and Description
static byte	ctrl_c
static byte[]	ctrlc

Fields inherited from class com.declarativa.interprolog.AbstractPrologEngine

firstJavaMessageName, interPrologFileLoaded, nl, prologBinDirectoryOrCommand

Fields inherited from interface com.declarativa.interprolog.PrologEngine

MAX_INT_VALUE, MIN_INT_VALUE, version

Method Summary

Modifier and Type	Method and Description
void	abortEngine() Assumes the engine is in a break state
void	addPrologOutputListener(PrologOutputListener client) Add a PrologOutputListener to this engine.
void	addPrologStderrListener(OutputListener l)
void	addPrologStdoutListener(OutputListener client) Add a OutputListener to get output from Prolog's standard output.
void	breakEngine() Pause the computation and enter a break (sub shell) state
Object[]	deterministicGoal(String G, String OVar, Object[] objectsP, String RVars) Synchronously calls a Prolog goal.
String	getCharset() Current engine stream charset name
boolean	isAvailable() Prolog is thought to be idle
boolean	isDetectErrorMessages()
void	printPrologOutputToConsole() For debugging purposes only
void	printPrologOutputToFile(String F) For debugging purposes only e.g.: ipPrologEngine(E), java(E,printPrologOutputToFile(string('/MyDir/xsb-output.txt'))).
boolean	realCommand(String s) This implementation may get stuck if the command includes variables, because the Prolog top level interpreter may offer to compute more solutions; use variables prefixed with '_'
void	removePrologOutputListener(PrologOutputListener client)
void	removePrologStderrListener(OutputListener l)
void	removePrologStdoutListener(OutputListener l)
void	resumeEngine() Assumes the engine is in a break state
void	sendAndFlush(String s) Sends a String to Prolog's input.
void	sendAndFlushLn(String s)
void	setCharset(String charsetName) Set the character set to be assumed decoding Prolog's stream output, e.g.
void	setDebug(boolean debug) Show (or hide) debug messages, both Java and Prolog side, cf.
void	setDetectErrorMessages(boolean detectErrorMessages) Some Prolog errors during deterministicGoal are not caught as exceptions, e.g.
void	setEngineStarted()
void	setSlowWindowsShutdown()
void	shutdown() Shuts down the background Prolog process as well as the dependent Java threads.
void	waitUntilAvailable() This method blocks until isAvailable() returns true.

Methods inherited from class com.declarativa.interprolog.AbstractPrologEngine

abortTasks, add_lib_dir, addPrologEngineListener, addSoftwareLibrary, addSoftwareLibrary, assignableType, command, command, command, consultAbsolute, consultAbsolute, consultFromPackage, consultFromPackage, consultRelative, createTempDirectory, currentTimeSecs, deleteAll, deleteTempFiles, deterministicGoal, deterministicGoal, deterministicGoal, deterministicGoal, deterministicGoalJSON, doCallback, endAllTasks, exec, executingOnJavaSide, findConstructor, findMethod, firstJavaMessage, getImplementationPeer, getInterprologPath, getJarDirectory, getJarDirectory, getLoadFromJar, getPrologBaseDirectory, getPrologNumericVersion, getPrologVersion, getRealJavaObject, getRealJavaObject, getRealJavaObject, getThePrologListener, goal, goal, handleCallback, hasPrologExtension, inPrologShell, interrupt, interruptTasks, is64WindowsOS, isAllowSimultaneousThreads, isDebug, isIdle, isLinuxOS, isMacOS, isPaused, isProfiling, isSerializable, isShutingDown, isThreadedCallbacks, isWindowsOS, lastSolutionUndefined, load_dynAbsolute, load_dynRelative, loop, loop2, makeInvisible, printAllStackTraces, printAllStackTraces, printBindings, printStackTrace, profilingMessage, progressMessage, progressMessage, prologBinToBaseDirectory, prologCanWork, prologEnteredBreak, prologResumedComputation, prologReturnedToTopLevel, registerJavaObject, removePrologEngineListener, serverFileSeparatorChar, serverIsWindows, setAllowSimultaneousThreads, setProfiling, setThreadedCallbacks, setTimedCallIntervall, shortClassName, stop, teachMoreObjects, teachMoreObjects, teachMoreObjects, teachOneObject, toString, unescapedFilePath, unregisterJavaObject, unregisterJavaObject, unregisterJavaObjects, waitUntilIdle

Methods inherited from class java.lang.Object

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

Field Detail

ctrl_c

public static byte ctrl_c

ctrlc

public static byte[] ctrlc

Method Detail

isDetectErrorMessages

public boolean isDetectErrorMessages()

Returns:

the detectErrorMessages

setDetectErrorMessages

public void setDetectErrorMessages(boolean detectErrorMessages)

Some Prolog errors during deterministicGoal are not caught as exceptions, e.g. in XSB: ++Error[XSB]: [Runtime/C] Overflow in integer, returning MAX_INT ...during reads. So this engine (by default) looks for error markers too.

Parameters:

detectErrorMessages - false if you want to disable textual detection of errors

addPrologOutputListener

public void addPrologOutputListener(PrologOutputListener client)

Add a PrologOutputListener to this engine. All stdout and stderr output will be routed to the client.

Parameters:

client - An object interested in receiving messages depicting Prolog's progress

See Also:

PrologOutputListener

removePrologOutputListener

public void removePrologOutputListener(PrologOutputListener client)

addPrologStdoutListener

public void addPrologStdoutListener(OutputListener client)

Add a OutputListener to get output from Prolog's standard output. This is a lower level interface than addPrologOutputListener(PrologOutputListener).

Parameters:

client - An object interested in Prolog's standard output

See Also:

OutputListener

addPrologStderrListener

public void addPrologStderrListener(OutputListener l)

removePrologStdoutListener

public void removePrologStdoutListener(OutputListener l)

removePrologStderrListener

public void removePrologStderrListener(OutputListener l)

setCharset

public void setCharset(String charsetName)

Set the character set to be assumed decoding Prolog's stream output, e.g. for Unicode: ?- ipPrologEngine(E), java(E,setCharset(string('UTF-8'))).

Parameters:

charsetName -

See Also:

Charset

getCharset

public String getCharset()

Current engine stream charset name

printPrologOutputToConsole

public void printPrologOutputToConsole()

For debugging purposes only

printPrologOutputToFile

public void printPrologOutputToFile(String F)
                             throws FileNotFoundException

For debugging purposes only e.g.: ipPrologEngine(E), java(E,printPrologOutputToFile(string('/MyDir/xsb-output.txt'))).

Throws:

FileNotFoundException

setEngineStarted

public void setEngineStarted()

setDebug

public void setDebug(boolean debug)

Description copied from class: AbstractPrologEngine

Show (or hide) debug messages, both Java and Prolog side, cf. ipIsDebugging/0. Beware that this may try to assert/retract a flag (ipIsDebugging/0) on the Prolog side, be sure to invoke this method sooner rather than later as it may get "stuck" if there are problems communicating with the Prolog engine

Specified by:

setDebug in interface PrologEngine

Overrides:

setDebug in class AbstractPrologEngine

isAvailable

public boolean isAvailable()

Prolog is thought to be idle

Specified by:

isAvailable in interface PrologEngine

Overrides:

isAvailable in class AbstractPrologEngine

waitUntilAvailable

public void waitUntilAvailable()

Description copied from interface: PrologEngine

This method blocks until isAvailable() returns true.

Specified by:

waitUntilAvailable in interface PrologEngine

Overrides:

waitUntilAvailable in class AbstractPrologEngine

shutdown

public void shutdown()

Shuts down the background Prolog process as well as the dependent Java threads.

Specified by:

shutdown in interface PrologEngine

Overrides:

shutdown in class AbstractPrologEngine

setSlowWindowsShutdown

public void setSlowWindowsShutdown()

sendAndFlush

public void sendAndFlush(String s)

Sends a String to Prolog's input. Its meaning will naturally depend on the current state of Prolog: it can be a top goal, or input to an ongoing computation

sendAndFlushLn

public void sendAndFlushLn(String s)

breakEngine

public void breakEngine()

Pause the computation and enter a break (sub shell) state

resumeEngine

public void resumeEngine()

Assumes the engine is in a break state

abortEngine

public void abortEngine()

Assumes the engine is in a break state

realCommand

public boolean realCommand(String s)

This implementation may get stuck if the command includes variables, because the Prolog top level interpreter may offer to compute more solutions; use variables prefixed with '_'

Specified by:

realCommand in class AbstractPrologEngine

See Also:

AbstractPrologEngine.command(String)

deterministicGoal

public Object[] deterministicGoal(String G,
                                  String OVar,
                                  Object[] objectsP,
                                  String RVars)

Description copied from class: AbstractPrologEngine

Synchronously calls a Prolog goal. Only the first solution is considered. G should contain a syntactically correct Prolog term, without the trailing dot (.). Throws an IPAbortedException if a Prolog abort happens, and an IPInterruptedException if the interrupt() method was invoked.

Specified by:

deterministicGoal in interface PrologEngine

Overrides:

deterministicGoal in class AbstractPrologEngine

Parameters:

G - Prolog goal term

OVar - Prolog variable that will be bound to objectsP array

objectsP - Array of Java objects to pass to Prolog goal; nonserializable objects are encapsulated in InvisibleObject references, changing this array

RVars - Prolog list with object specifications, typically containing variables occurring in g. If null a single binding will be returned, containing a TermModel object representing the goal term solution

Returns:

a new array containing an object for each term in the rVars list, or null if goal fails

See Also:

AbstractPrologEngine.deterministicGoal(String), AbstractPrologEngine.deterministicGoal(String,String), AbstractPrologEngine.deterministicGoal(String,String,Object[])