This is an automated email from the ASF dual-hosted git repository.
henrib pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-jexl.git
commit a4c4cc996b1405e1d93f8c59d0d4c3670aefffd2
Author: henrib <hen...@apache.org>
AuthorDate: Mon Dec 2 17:08:09 2019 +0100
JEXL-317: added optional interface JexlContext.CancellationHandle
Task #JEXL-317 - Support script cancellation through less invasive API
---
RELEASE-NOTES.txt | 1 +
.../java/org/apache/commons/jexl3/JexlContext.java | 15 +++++++
.../apache/commons/jexl3/internal/Interpreter.java | 3 +-
.../commons/jexl3/internal/InterpreterBase.java | 18 ++++----
src/site/xdoc/changes.xml | 3 ++
.../apache/commons/jexl3/ScriptCallableTest.java | 51 +++++++++++++++++++++-
6 files changed, 81 insertions(+), 10 deletions(-)
diff --git a/RELEASE-NOTES.txt b/RELEASE-NOTES.txt
index 6a6ee8d..23ce03f 100644
--- a/RELEASE-NOTES.txt
+++ b/RELEASE-NOTES.txt
@@ -48,6 +48,7 @@ What's new in 3.2:
New Features in 3.2:
====================
+* JEXL-317: Support script cancellation through less invasive API
* JEXL-307: Variable redeclaration option
* JEXL-295: Add unary plus operator
* JEXL-292: Allow specifying custom Permissions class for Uberspect to be
used later by Introspector
diff --git a/src/main/java/org/apache/commons/jexl3/JexlContext.java
b/src/main/java/org/apache/commons/jexl3/JexlContext.java
index 2f4d69e..7a9c828 100644
--- a/src/main/java/org/apache/commons/jexl3/JexlContext.java
+++ b/src/main/java/org/apache/commons/jexl3/JexlContext.java
@@ -18,6 +18,7 @@
package org.apache.commons.jexl3;
import java.util.concurrent.Callable;
+import java.util.concurrent.atomic.AtomicBoolean;
/**
* Manages variables which can be referenced in a JEXL expression.
@@ -175,4 +176,18 @@ public interface JexlContext {
*/
void processPragma(String key, Object value);
}
+
+ /**
+ * A marker interface of the JexlContext sharing a cancelling flag.
+ * <p>A script running in a thread can thus be notified through this
reference
+ * of its cancellation through the context. It uses the same interpreter
logic
+ * that reacts to cancellation and is an alternative to using callable()
and/or
+ * interrupting script interpreter threads.
+ */
+ interface CancellationHandle {
+ /**
+ * @return a cancelable boolean used by the interpreter
+ */
+ AtomicBoolean getCancellation();
+ }
}
diff --git a/src/main/java/org/apache/commons/jexl3/internal/Interpreter.java
b/src/main/java/org/apache/commons/jexl3/internal/Interpreter.java
index 9c27f61..dac5b49 100644
--- a/src/main/java/org/apache/commons/jexl3/internal/Interpreter.java
+++ b/src/main/java/org/apache/commons/jexl3/internal/Interpreter.java
@@ -200,7 +200,8 @@ public class Interpreter extends InterpreterBase {
} catch (JexlException.Return xreturn) {
return xreturn.getValue();
} catch (JexlException.Cancel xcancel) {
- cancelled |= Thread.interrupted();
+ // cancelled |= Thread.interrupted();
+ cancelled.weakCompareAndSet(false, Thread.interrupted());
if (isCancellable()) {
throw xcancel.clean();
}
diff --git
a/src/main/java/org/apache/commons/jexl3/internal/InterpreterBase.java
b/src/main/java/org/apache/commons/jexl3/internal/InterpreterBase.java
index 504c1c1..3f4f2d0 100644
--- a/src/main/java/org/apache/commons/jexl3/internal/InterpreterBase.java
+++ b/src/main/java/org/apache/commons/jexl3/internal/InterpreterBase.java
@@ -20,6 +20,7 @@ package org.apache.commons.jexl3.internal;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
+import java.util.concurrent.atomic.AtomicBoolean;
import org.apache.commons.jexl3.JexlArithmetic;
import org.apache.commons.jexl3.JexlContext;
import org.apache.commons.jexl3.JexlEngine;
@@ -63,7 +64,7 @@ public abstract class InterpreterBase extends ParserVisitor {
/** Cache executors. */
protected final boolean cache;
/** Cancellation support. */
- protected volatile boolean cancelled = false;
+ protected final AtomicBoolean cancelled;
/** Empty parameters for method matching. */
protected static final Object[] EMPTY_PARAMS = new Object[0];
/** The context to store/retrieve variables. */
@@ -100,6 +101,11 @@ public abstract class InterpreterBase extends
ParserVisitor {
} else {
ns = Engine.EMPTY_NS;
}
+ AtomicBoolean acancel = null;
+ if (this.context instanceof JexlContext.CancellationHandle) {
+ acancel = ((JexlContext.CancellationHandle)
context).getCancellation();
+ }
+ this.cancelled = acancel != null? acancel : new AtomicBoolean(false);
this.functions = jexl.functions;
this.functors = null;
this.operators = new Operators(this);
@@ -118,6 +124,7 @@ public abstract class InterpreterBase extends ParserVisitor
{
arithmetic = ii.arithmetic;
cache = ii.cache;
ns = ii.ns;
+ cancelled = ii.cancelled;
functions = ii.functions;
functors = ii.functors;
operators = ii.operators;
@@ -544,12 +551,7 @@ public abstract class InterpreterBase extends
ParserVisitor {
* @return false if already cancelled, true otherwise
*/
protected boolean cancel() {
- if (cancelled) {
- return false;
- } else {
- cancelled = true;
- return true;
- }
+ return cancelled.compareAndSet(false, true);
}
/**
@@ -557,7 +559,7 @@ public abstract class InterpreterBase extends ParserVisitor
{
* @return true if cancelled, false otherwise
*/
protected boolean isCancelled() {
- return cancelled | Thread.currentThread().isInterrupted();
+ return cancelled.get() | Thread.currentThread().isInterrupted();
}
/**
diff --git a/src/site/xdoc/changes.xml b/src/site/xdoc/changes.xml
index 24e4b2a..7ecbf0c 100644
--- a/src/site/xdoc/changes.xml
+++ b/src/site/xdoc/changes.xml
@@ -26,6 +26,9 @@
</properties>
<body>
<release version="3.2" date="unreleased">
+ <action dev="henrib" type="add" issue="JEXL-317">
+ Support script cancellation through less invasive API
+ </action>
<action dev="henrib" type="fix" issue="JEXL-315" due-to="Mike
Bartlett">
JxltEngine literal string strings ending in \ $ or # throw
JxltEngine$Exception
</action>
diff --git a/src/test/java/org/apache/commons/jexl3/ScriptCallableTest.java
b/src/test/java/org/apache/commons/jexl3/ScriptCallableTest.java
index 313562d..63b5b0d 100644
--- a/src/test/java/org/apache/commons/jexl3/ScriptCallableTest.java
+++ b/src/test/java/org/apache/commons/jexl3/ScriptCallableTest.java
@@ -27,6 +27,7 @@ import java.util.concurrent.FutureTask;
import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
+import java.util.concurrent.atomic.AtomicBoolean;
import org.apache.commons.jexl3.internal.Script;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
@@ -67,7 +68,6 @@ public class ScriptCallableTest extends JexlTestCase {
@Test
public void testCallableCancel() throws Exception {
- List<Runnable> lr = null;
final Semaphore latch = new Semaphore(0);
JexlContext ctxt = new MapContext();
ctxt.set("latch", latch);
@@ -85,6 +85,7 @@ public class ScriptCallableTest extends JexlTestCase {
ExecutorService executor = Executors.newFixedThreadPool(2);
Future<?> future = executor.submit(c);
Future<?> kfc = executor.submit(kc);
+ List<Runnable> lr;
try {
Assert.assertTrue((Boolean) kfc.get());
t = future.get();
@@ -98,7 +99,55 @@ public class ScriptCallableTest extends JexlTestCase {
Assert.assertTrue(c.isCancelled());
Assert.assertTrue(lr == null || lr.isEmpty());
}
+
+ public static class CancellationContext extends MapContext implements
JexlContext.CancellationHandle {
+ private final AtomicBoolean cancellation;
+
+ CancellationContext(AtomicBoolean c) {
+ cancellation = c;
+ }
+ @Override
+ public AtomicBoolean getCancellation() {
+ return cancellation;
+ }
+ }
+
+ // JEXL-317
+ @Test
+ public void testCallableCancellation() throws Exception {
+ final Semaphore latch = new Semaphore(0);
+ final AtomicBoolean cancel = new AtomicBoolean(false);
+ JexlContext ctxt = new CancellationContext(cancel);
+ ctxt.set("latch", latch);
+ JexlScript e = JEXL.createScript("latch.release(); while(true);");
+ final Script.Callable c = (Script.Callable) e.callable(ctxt);
+ Object t = 42;
+ Callable<Object> kc = new Callable<Object>() {
+ @Override
+ public Object call() throws Exception {
+ latch.acquire();
+ return cancel.compareAndSet(false, true);
+ }
+ };
+ ExecutorService executor = Executors.newFixedThreadPool(2);
+ Future<?> future = executor.submit(c);
+ Future<?> kfc = executor.submit(kc);
+ List<Runnable> lr;
+ try {
+ Assert.assertTrue((Boolean) kfc.get());
+ t = future.get();
+ Assert.fail("should have been cancelled");
+ } catch (ExecutionException xexec) {
+ // ok, ignore
+ Assert.assertTrue(xexec.getCause() instanceof
JexlException.Cancel);
+ } finally {
+ lr = executor.shutdownNow();
+ }
+ Assert.assertTrue(c.isCancelled());
+ Assert.assertTrue(lr == null || lr.isEmpty());
+ }
+
@Test
public void testCallableTimeout() throws Exception {
List<Runnable> lr = null;
