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Event-driven lists for dynamically filtered and sorted tables
/* Glazed Lists (c) 2003-2006 */
/* http://publicobject.com/glazedlists/ publicobject.com,*/
/* O'Dell Engineering Ltd.*/
package ca.odell.glazedlists.event;
import ca.odell.glazedlists.*;
import ca.odell.glazedlists.impl.testing.GlazedListsTests;
import ca.odell.glazedlists.impl.testing.ListConsistencyListener;
import junit.framework.TestCase;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
/**
* Make sure that the {@link SequenceDependenciesEventPublisher} class fires events properly.
*
* @author Jesse Wilson
*/
public class SequenceDependenciesEventPublisherTest extends TestCase {
/**
* Make sure that all events get fired to all listeners.
*/
public void testVeryBasicChain() {
SequenceDependenciesEventPublisher publisher = new SequenceDependenciesEventPublisher();
SimpleSubjectListener a = new SimpleSubjectListener("A", publisher);
SimpleSubjectListener b = new SimpleSubjectListener("B", publisher);
SimpleSubjectListener c = new SimpleSubjectListener("C", publisher);
a.setValue("apple");
assertEquals("apple", a.getValue());
assertEquals(null, b.getValue());
assertEquals(null, c.getValue());
a.addListener(b);
a.setValue("banana");
assertEquals("banana", a.getValue());
assertEquals("[A:banana]", b.getValue());
assertEquals(null, c.getValue());
a.addListener(c);
a.setValue("chocolate");
assertEquals("chocolate", a.getValue());
assertEquals("[A:chocolate]", b.getValue());
assertEquals("[A:chocolate]", c.getValue());
a.removeListener(b);
a.setValue("ducks");
assertEquals("ducks", a.getValue());
assertEquals("[A:chocolate]", b.getValue());
assertEquals("[A:ducks]", c.getValue());
c.addListener(b);
a.setValue("elephants");
assertEquals("elephants", a.getValue());
assertEquals("[C:[A:elephants]]", b.getValue());
assertEquals("[A:elephants]", c.getValue());
c.setValue("foxes");
assertEquals("elephants", a.getValue());
assertEquals("[C:foxes]", b.getValue());
assertEquals("foxes", c.getValue());
a.removeListener(c);
a.setValue("gorillas");
assertEquals("gorillas", a.getValue());
assertEquals("[C:foxes]", b.getValue());
assertEquals("foxes", c.getValue());
a.addListener(c);
a.setValue("horses");
assertEquals("horses", a.getValue());
assertEquals("[C:[A:horses]]", b.getValue());
assertEquals("[A:horses]", c.getValue());
}
/**
* A simple class that is both the listener and the subject, useful only
* for testing.
*/
private static class SimpleSubjectListener {
private final String name;
private final SequenceDependenciesEventPublisher publisher;
/** a string, automatically set when events are received */
private String value = null;
/** a log of events received */
private List receivedEvents = new ArrayList();
/** an arbitrary runnable to run when the next event is received */
public Runnable runOnceRunnable;
public SimpleSubjectListener(String name, SequenceDependenciesEventPublisher publisher) {
this.name = name;
this.publisher = publisher;
}
public void addListener(SimpleSubjectListener listener) {
publisher.addListener(SimpleSubjectListener.this, listener, SimpleSubjectListenerEventFormat.INSTANCE);
}
public void removeListener(SimpleSubjectListener listener) {
publisher.removeListener(SimpleSubjectListener.this, listener);
}
public void handleChange(String value) {
// remember the event
receivedEvents.add(value);
// execute any requested code
try {
if(runOnceRunnable != null) {
runOnceRunnable.run();
}
} finally {
runOnceRunnable = null;
}
// apply this change
setValue(value);
}
public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
publisher.fireEvent(this, "[" + name + ":" + this.value + "]", SimpleSubjectListenerEventFormat.INSTANCE);
}
public String toString() {
return name;
}
public List getReceivedEvents() {
return receivedEvents;
}
public void setRunOnceRunnable(Runnable runnable) {
this.runOnceRunnable = runnable;
}
}
/**
* Adapt {@link SimpleSubjectListener} for firing events.
*/
private static class SimpleSubjectListenerEventFormat implements SequenceDependenciesEventPublisher.EventFormat {
public static final SimpleSubjectListenerEventFormat INSTANCE = new SimpleSubjectListenerEventFormat();
public void fire(SimpleSubjectListener subject, String event, SimpleSubjectListener listener) {
listener.handleChange(event);
}
public void postEvent(SimpleSubjectListener subject) {
// do nothing
}
public boolean isStale(SimpleSubjectListener subject, SimpleSubjectListener listener) {
return false;
}
}
/**
* Prepare the original diamond-dependency problem, where B depends on A
* and C depends on both A and B. We need to guarantee that C can read
* all of its dependencies only when they're in a 'consistent' state,
* which is when they've received all events from their dependencies,
* and their dependencies are in a consistent state.
*
* A --> B --. This diagram shows A --> B, B --> C and A --> C.
* | | The only safe notification order of events is
* | V for B to receive events from A before C receives
* '-------> C those same events.
*/
public void testDiamondDependency() {
SequenceDependenciesEventPublisher publisher = new SequenceDependenciesEventPublisher();
DependentSubjectListener a = new DependentSubjectListener("A", publisher);
DependentSubjectListener b = new DependentSubjectListener("B", publisher);
DependentSubjectListener c = new DependentSubjectListener("C", publisher);
a.addListener(c);
a.increment(10);
assertEquals(10, a.latestRevision);
assertEquals( 0, b.latestRevision);
assertEquals(10, c.latestRevision);
c.increment(5);
assertEquals(10, a.latestRevision);
assertEquals( 0, b.latestRevision);
assertEquals(15, c.latestRevision);
b.increment(20);
assertEquals(10, a.latestRevision);
assertEquals(20, b.latestRevision);
assertEquals(15, c.latestRevision);
b.addListener(c);
assertEquals(10, a.latestRevision);
assertEquals(20, b.latestRevision);
assertEquals(20, c.latestRevision);
b.increment(2);
assertEquals(10, a.latestRevision);
assertEquals(22, b.latestRevision);
assertEquals(22, c.latestRevision);
a.increment(15);
assertEquals(25, a.latestRevision);
assertEquals(22, b.latestRevision);
assertEquals(25, c.latestRevision);
a.addListener(b);
assertEquals(25, a.latestRevision);
assertEquals(25, b.latestRevision);
assertEquals(25, c.latestRevision);
a.increment(4);
assertEquals(29, a.latestRevision);
assertEquals(29, b.latestRevision);
assertEquals(29, c.latestRevision);
}
/**
* The publisher should throw an IllegalStateException when a cycle in the
* listener graph is created.
*/
public void testCycleThrows() {
SequenceDependenciesEventPublisher publisher = new SequenceDependenciesEventPublisher();
DependentSubjectListener a = new DependentSubjectListener("A", publisher);
DependentSubjectListener b = new DependentSubjectListener("B", publisher);
DependentSubjectListener c = new DependentSubjectListener("C", publisher);
// simple cycle of three
a.addListener(b);
b.addListener(c);
try {
c.addListener(a);
fail("Cycle not detected");
} catch(IllegalStateException e) {
// expected
}
// cycle of 10
publisher = new SequenceDependenciesEventPublisher();
DependentSubjectListener[] subjects = new DependentSubjectListener[10];
for(int i = 0; i < 10; i++) {
subjects[i] = new DependentSubjectListener("" + i, publisher);
if(i > 0) subjects[i-1].addListener(subjects[i]);
}
try {
subjects[9].addListener(subjects[0]);
fail("Cycle not detected");
} catch(IllegalStateException e) {
// expected
}
// cycle of 1
publisher = new SequenceDependenciesEventPublisher();
a = new DependentSubjectListener("A", publisher);
try {
a.addListener(a);
fail("Cycle not detected");
} catch(IllegalStateException e) {
// expected
}
}
/**
* An interesting subject that uses a single integer to maintain state. The
* integer can increase at any subject, and all downstream listeners must
* be notified of this change. If ever a listener's integer is less than that
* of its dependency, then it did not receive notification from that
* dependency and we have a terrible problem!
*/
public static class DependentSubjectListener {
private SequenceDependenciesEventPublisher publisher;
/** a monotonically increasing revision number */
int latestRevision = 0;
/** useful for debugging */
private final String name;
/** objects I depend on, must all be consistent for this to be consistent */
List upstreamSubjects = new ArrayList();
/** objects that depend on me */
List downstreamListeners = new ArrayList();
public DependentSubjectListener(String name, SequenceDependenciesEventPublisher publisher) {
this.publisher = publisher;
this.name = name;
}
public String toString() {
return name + ":" + latestRevision;
}
public void increment(int amount) {
this.latestRevision += amount;
this.publisher.fireEvent(this, new Integer(this.latestRevision), DependentSubjectListenerEventFormat.INSTANCE);
}
/**
* Register the listener as dependent on the subject.
*/
public void addListener(DependentSubjectListener listener) {
downstreamListeners.add(listener);
listener.upstreamSubjects.add(this);
listener.latestRevision = Math.max(listener.latestRevision, latestRevision);
this.publisher.addListener(this, listener, DependentSubjectListenerEventFormat.INSTANCE);
}
/**
* Dependencies are satisfied if the latestRevision is at least the
* latestRevision of all upstream {@link DependentSubjectListener}s.
*/
public void assertDependenciesSatisfiedRecursively(DependentSubjectListener notified) {
final Iterator iter = upstreamSubjects.iterator();
while(iter.hasNext()) {
final DependentSubjectListener upstream = iter.next();
upstream.assertDependenciesSatisfiedRecursively(notified);
if(latestRevision < upstream.latestRevision)
throw new IllegalStateException("Dependencies not satisfied for " + notified + ", dependency " + this + " not updated by " + upstream + "!");
}
}
}
/**
* Adapt {@link SimpleSubjectListener} for firing events.
*/
private static class DependentSubjectListenerEventFormat implements SequenceDependenciesEventPublisher.EventFormat {
public static final DependentSubjectListenerEventFormat INSTANCE = new DependentSubjectListenerEventFormat();
public void fire(DependentSubjectListener subject, Integer event, DependentSubjectListener listener) {
// update the listener
boolean incremented = listener.latestRevision < event.intValue();
listener.latestRevision = event.intValue();
// make sure the listener's dependencies were notified first
listener.assertDependenciesSatisfiedRecursively(listener);
// send the event forward
if(incremented) {
listener.increment(0);
}
}
public void postEvent(DependentSubjectListener subject) {
// do nothing
}
public boolean isStale(DependentSubjectListener subject, DependentSubjectListener listener) {
return false;
}
}
/**
* Make sure that when the listener graph changes during an event, it gets
* processed only at the conclusion of that event.
*/
public void testRemovesAndAddsDuringEvent() {
SequenceDependenciesEventPublisher publisher = new SequenceDependenciesEventPublisher();
SimpleSubjectListener a = new SimpleSubjectListener("A", publisher);
SimpleSubjectListener b = new SimpleSubjectListener("B", publisher);
SimpleSubjectListener c = new SimpleSubjectListener("C", publisher);
SimpleSubjectListener d = new SimpleSubjectListener("D", publisher);
a.addListener(b);
// add c as a listener to b, it shouldn't receive the first event
b.setRunOnceRunnable(new AddListenerRunnable(b, c));
a.setValue("Saskatchwan");
assertEquals(1, b.getReceivedEvents().size());
assertEquals(0, c.getReceivedEvents().size());
a.setValue("Tiger-Cats");
assertEquals(2, b.getReceivedEvents().size());
assertEquals(1, c.getReceivedEvents().size());
// remove c as a listener to b, it should still receive the event
b.setRunOnceRunnable(new RemoveListenerRunnable(b, c));
a.setValue("Blue Bombers");
assertEquals(3, b.getReceivedEvents().size());
assertEquals(2, c.getReceivedEvents().size());
a.setValue("Stampeders");
assertEquals(4, b.getReceivedEvents().size());
assertEquals(2, c.getReceivedEvents().size());
// add a completely unrelated listener b to do events for c and d
a.addListener(c);
b.setRunOnceRunnable(new AddListenerRunnable(c, d));
a.setValue("Argonauts");
assertEquals(3, c.getReceivedEvents().size());
assertEquals(0, d.getReceivedEvents().size());
a.setValue("Lions");
assertEquals(4, c.getReceivedEvents().size());
assertEquals(1, d.getReceivedEvents().size());
// remove the unrelated listener b to do events for c and d
b.setRunOnceRunnable(new RemoveListenerRunnable(c, d));
a.setValue("Eskimos");
assertEquals(5, c.getReceivedEvents().size());
assertEquals(2, d.getReceivedEvents().size());
a.setValue("Alouettes");
assertEquals(6, c.getReceivedEvents().size());
assertEquals(2, d.getReceivedEvents().size());
}
/**
* Make sure we throw an exception when attempting to remove something that's
* not a listener.
*/
public void testUnknownRemoveThrowsException() {
SequenceDependenciesEventPublisher publisher = new SequenceDependenciesEventPublisher();
SimpleSubjectListener a = new SimpleSubjectListener("A", publisher);
SimpleSubjectListener b = new SimpleSubjectListener("B", publisher);
SimpleSubjectListener c = new SimpleSubjectListener("C", publisher);
// add a listener
a.addListener(b);
try {
a.removeListener(c);
fail("No exception thrown when removing a non-existent listener");
} catch(IllegalArgumentException e) {
// expected
}
// remove the other listener, this shouldn't throw
a.removeListener(b);
}
/**
* Add a listener when executed.
*/
private static class AddListenerRunnable implements Runnable {
private SimpleSubjectListener subject;
private SimpleSubjectListener listener;
public AddListenerRunnable(SimpleSubjectListener subject, SimpleSubjectListener listener) {
this.subject = subject;
this.listener = listener;
}
public void run() {
subject.addListener(listener);
}
}
/**
* Remove a listener when executed.
*/
private static class RemoveListenerRunnable implements Runnable {
private SimpleSubjectListener subject;
private SimpleSubjectListener listener;
public RemoveListenerRunnable(SimpleSubjectListener subject, SimpleSubjectListener listener) {
this.subject = subject;
this.listener = listener;
}
public void run() {
subject.removeListener(listener);
}
}
/**
* This test currently fails in the graph publisher implementation because
* we don't support merging events in GraphDependenciesListEventPublisher.
*/
public void testMergingListEvents() {
CompositeList compositeList = new CompositeList();
ListConsistencyListener listConsistencyListener = ListConsistencyListener.install(compositeList);
listConsistencyListener.setPreviousElementTracked(false);
EventList source = compositeList.createMemberList();
source.add("C");
source.add("A");
source.add("B");
SortedList forwardSource = SortedList.create(source);
SortedList reverseSource = new SortedList(source, GlazedLists.reverseComparator());
compositeList.addMemberList(forwardSource);
compositeList.addMemberList(source);
compositeList.addMemberList(reverseSource);
assertEquals(compositeList, GlazedListsTests.stringToList("ABCCABCBA"));
source.add(1, "D");
assertEquals(compositeList, GlazedListsTests.stringToList("ABCDCDABDCBA"));
source.removeAll(GlazedListsTests.stringToList("AC"));
assertEquals(compositeList, GlazedListsTests.stringToList("BDDBDB"));
source.clear();
assertEquals(compositeList, GlazedListsTests.stringToList(""));
source.addAll(GlazedListsTests.stringToList("CADB"));
assertEquals(compositeList, GlazedListsTests.stringToList("ABCDCADBDCBA"));
}
/**
* Test that listeners and subjects do not have to use the same identity
* so long as {@link ListEventPublisher#setRelatedSubject} is used.
*/
public void testRelatedSubjects() {
SequenceDependenciesEventPublisher publisher = new SequenceDependenciesEventPublisher();
DetachedSubject a = new DetachedSubject("A", publisher);
DetachedSubject b = new DetachedSubject("B", publisher);
DetachedSubject c = new DetachedSubject("C", publisher);
DetachedSubject d = new DetachedSubject("D", publisher);
DetachedSubject e = new DetachedSubject("E", publisher);
b.addListener(e);
a.addListener(b);
c.addListener(e);
a.addListener(c);
d.addListener(e);
a.addListener(d);
// changing a should impact e, but only after b, c, and d
a.increment(10);
assertEquals(10, a.latestRevision);
assertEquals(10, b.latestRevision);
assertEquals(10, c.latestRevision);
assertEquals(10, d.latestRevision);
assertEquals(10, e.latestRevision);
}
/**
* A subject that listens to another subject via an inner listener class.
* This is used to test that listener identity is not required.
*/
private static class DetachedSubject {
private SequenceDependenciesEventPublisher publisher;
private String name;
private int latestRevision = 0;
private List upstreamSubjects = new ArrayList();
public DetachedSubject(String name, SequenceDependenciesEventPublisher publisher) {
this.name = name;
this.publisher = publisher;
}
public String toString() {
return name;
}
public void addListener(DetachedSubject listener) {
listener.upstreamSubjects.add(this);
Listener innerListener = new Listener(listener);
publisher.setRelatedSubject(innerListener, innerListener.subject);
publisher.addListener(this, innerListener, DetachedSubjectAndListenerEventFormat.INSTANCE);
}
public void increment(int amount) {
this.latestRevision += amount;
publisher.fireEvent(this, new Integer(this.latestRevision), DetachedSubjectAndListenerEventFormat.INSTANCE);
}
/**
* Dependencies are satisfied if the latestRevision is at least the
* latestRevision of all upstream {@link DependentSubjectListener}s.
*/
public void assertDependenciesSatisfiedRecursively(DetachedSubject notified) {
final Iterator iter = upstreamSubjects.iterator();
while(iter.hasNext()) {
final DetachedSubject upstream = iter.next();
upstream.assertDependenciesSatisfiedRecursively(notified);
if(latestRevision < upstream.latestRevision) {
throw new IllegalStateException("Dependencies not satisfied for " + notified + ", dependency " + this + " not updated by " + upstream + "!");
}
}
}
private static class Listener {
private DetachedSubject subject;
public Listener(DetachedSubject subject) {
this.subject = subject;
}
public String toString() {
return "L(" + subject.name + ")";
}
}
}
/**
* Adapt {@link DetachedSubject} and {@link DetachedSubject.Listener} for firing events.
*/
private static class DetachedSubjectAndListenerEventFormat implements SequenceDependenciesEventPublisher.EventFormat {
public static final DetachedSubjectAndListenerEventFormat INSTANCE = new DetachedSubjectAndListenerEventFormat();
public void fire(DetachedSubject subject, Integer event, DetachedSubject.Listener listener) {
boolean changed = listener.subject.latestRevision < event.intValue();
// update the listener
listener.subject.latestRevision = event.intValue();
// make sure the listener's dependencies were notified first
listener.subject.assertDependenciesSatisfiedRecursively(listener.subject);
// send the event forward
if(changed) listener.subject.increment(0);
}
public void postEvent(DetachedSubject subject) {
// do nothing
}
public boolean isStale(DetachedSubject subject, DetachedSubject.Listener listener) {
return false;
}
}
/**
* Test that the ListEvent iterator isn't adjusted by calling
* {@link ListEventAssembler#forwardEvent}.
*/
public void testEventStateAfterForwardEvent() {
EventList source = new BasicEventList();
ListConsistencyListener lcl = ListConsistencyListener.install(source);
source.add("Hello");
assertEquals(1, lcl.getChangeCount(0));
}
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