Updated accumulator documentation and refactored names to remove the event heritage.

Change-Id: I2238ab1215281702e670a406fb901ba8a4ef85ce
diff --git a/utils/misc/src/test/java/org/onlab/util/AbstractAccumulatorTest.java b/utils/misc/src/test/java/org/onlab/util/AbstractAccumulatorTest.java
new file mode 100644
index 0000000..b2b0b1f
--- /dev/null
+++ b/utils/misc/src/test/java/org/onlab/util/AbstractAccumulatorTest.java
@@ -0,0 +1,111 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * 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.onlab.util;
+
+import org.junit.Ignore;
+import org.junit.Test;
+
+import java.util.List;
+import java.util.Timer;
+
+import static org.junit.Assert.*;
+import static org.onlab.junit.TestTools.delay;
+
+/**
+ * Tests the operation of the accumulator.
+ */
+public class AbstractAccumulatorTest {
+
+    private final Timer timer = new Timer();
+
+    @Test
+    public void basics() throws Exception {
+        TestAccumulator accumulator = new TestAccumulator();
+        assertEquals("incorrect timer", timer, accumulator.timer());
+        assertEquals("incorrect max events", 5, accumulator.maxItems());
+        assertEquals("incorrect max ms", 100, accumulator.maxBatchMillis());
+        assertEquals("incorrect idle ms", 50, accumulator.maxIdleMillis());
+    }
+
+    @Test
+    public void eventTrigger() {
+        TestAccumulator accumulator = new TestAccumulator();
+        accumulator.add(new TestItem("a"));
+        accumulator.add(new TestItem("b"));
+        accumulator.add(new TestItem("c"));
+        accumulator.add(new TestItem("d"));
+        assertTrue("should not have fired yet", accumulator.batch.isEmpty());
+        accumulator.add(new TestItem("e"));
+        delay(20);
+        assertFalse("should have fired", accumulator.batch.isEmpty());
+        assertEquals("incorrect batch", "abcde", accumulator.batch);
+    }
+
+    @Ignore("FIXME: timing sensitive test failing randomly.")
+    @Test
+    public void timeTrigger() {
+        TestAccumulator accumulator = new TestAccumulator();
+        accumulator.add(new TestItem("a"));
+        delay(30);
+        assertTrue("should not have fired yet", accumulator.batch.isEmpty());
+        accumulator.add(new TestItem("b"));
+        delay(30);
+        assertTrue("should not have fired yet", accumulator.batch.isEmpty());
+        accumulator.add(new TestItem("c"));
+        delay(30);
+        assertTrue("should not have fired yet", accumulator.batch.isEmpty());
+        accumulator.add(new TestItem("d"));
+        delay(30);
+        assertFalse("should have fired", accumulator.batch.isEmpty());
+        assertEquals("incorrect batch", "abcd", accumulator.batch);
+    }
+
+    @Test
+    public void idleTrigger() {
+        TestAccumulator accumulator = new TestAccumulator();
+        accumulator.add(new TestItem("a"));
+        assertTrue("should not have fired yet", accumulator.batch.isEmpty());
+        accumulator.add(new TestItem("b"));
+        delay(80);
+        assertFalse("should have fired", accumulator.batch.isEmpty());
+        assertEquals("incorrect batch", "ab", accumulator.batch);
+    }
+
+    private class TestItem {
+        private final String s;
+
+        public TestItem(String s) {
+            this.s = s;
+        }
+    }
+
+    private class TestAccumulator extends AbstractAccumulator<TestItem> {
+
+        String batch = "";
+
+        protected TestAccumulator() {
+            super(timer, 5, 100, 50);
+        }
+
+        @Override
+        public void processItems(List<TestItem> items) {
+            for (TestItem item : items) {
+                batch += item.s;
+            }
+        }
+    }
+
+}