--- /dev/null
+/*
+ * Copyright 2006 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.wamblee.test;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+/**
+ * Tracks the occurence of certain events in a test environment. Threads in a
+ * test environment tell the event tracker of the occurrence of certain events
+ * using {@link #eventOccurred(String)}. Test code inspects the events sent by
+ * a thread using {@link #isEventSent(Thread, String)}.
+ *
+ * A record is kept of every event which is sent. Therefore, the occurence of a
+ * new event does not erase a previously sent event.
+ *
+ * @param <Event> Type of event sent from test code. Usually String will be sufficient.
+ * The event type must provide a sensible implementation of {@link java.lang.Object#equals(java.lang.Object)}.
+ */
+public class EventTracker<Event> {
+
+ private static final Log LOG = LogFactory.getLog(EventTracker.class);
+
+ /**
+ * Map of Thread object to a list of events.
+ */
+ private Map<Thread, List<Event>> _events;
+
+ /**
+ * Constructs the event tracker.
+ *
+ */
+ public EventTracker() {
+ _events = new HashMap<Thread, List<Event>>();
+ }
+
+ /**
+ * Called by a thread to inform that an event has occurred.
+ *
+ * @param aEvent
+ * Event that was sent.
+ */
+ public synchronized void eventOccurred(Event aEvent) {
+ LOG.info("Event '" + aEvent + "' sent.");
+ Thread current = Thread.currentThread();
+ List<Event> events = _events.get(current);
+ if (events == null) {
+ events = new ArrayList<Event>();
+ _events.put(current, events);
+ }
+ events.add(aEvent);
+ }
+
+ /**
+ * Checks if a specific event has happened in a specific thread.
+ *
+ * @param aThread
+ * Thread to check.
+ * @param aEvent
+ * Event to check for.
+ * @return Whether or not the event was sent.
+ */
+ public synchronized boolean isEventSent(Thread aThread, Event aEvent) {
+ List<Event> events = _events.get(aThread);
+ if (events == null) {
+ return false;
+ }
+ return events.contains(aEvent);
+ }
+
+ /**
+ * Gets the events for a thread in the order they were sent
+ *
+ * @param aThread
+ * Thread to get events for.
+ * @return Events that were sent. A zero-sized array is returned if no
+ * events were sent.
+ */
+ public synchronized List<Event> getEvents(Thread aThread) {
+ List<Event> events = _events.get(aThread);
+ if (events == null) {
+ events = Collections.emptyList();
+ }
+ return Collections.unmodifiableList(events);
+ }
+
+ /**
+ * Gets the number of times an event was sent.
+ *
+ * @param aEvent
+ * Event to check.
+ * @return Number of times it was reached.
+ */
+ public synchronized int getEventCount(Event aEvent) {
+ int count = 0;
+ for (Thread thread : _events.keySet()) {
+ List<Event> events = _events.get(thread);
+ for (Event event : events) {
+ if (event.equals(aEvent)) {
+ count++;
+ }
+ }
+ }
+ return count;
+ }
+}