Fill in some missing Javadocs.

src/main/java/com/rapportive/storm/spout/AMQPSpout.java

@@ -71,7 +71,12 @@ public class AMQPSpout implements IRichSpout {
     public static final String CONFIG_PREFETCH_COUNT = "amqp.prefetch.count";
     private static final long DEFAULT_PREFETCH_COUNT = 100;
 
-    private static final long WAIT_FOR_NEXT_MESSAGE = 1L;
+    /**
+     * Time in milliseconds to wait for a message from the queue if there is
+     * no message ready when the topology requests a tuple (via
+     * {@link #nextTuple()}).
+     */
+    public static final long WAIT_FOR_NEXT_MESSAGE = 1L;
 
     private final String amqpHost;
     private final int amqpPort;
@@ -120,6 +125,9 @@ public AMQPSpout(String host, int port, String username, String password, String
     }
 
 
+    /**
+     * Acks the message with the AMQP broker.
+     */
     @Override
     public void ack(Object msgId) {
         if (msgId instanceof Long) {
@@ -137,6 +145,9 @@ public void ack(Object msgId) {
     }
 
 
+    /**
+     * Cancels the queue subscription, and disconnects from the AMQP broker.
+     */
     @Override
     public void close() {
         try {
@@ -161,6 +172,15 @@ public void close() {
     }
 
 
+    /**
+     * Tells the AMQP broker to drop (Basic.Reject) the message.
+     *
+     * <p><strong>N.B.</strong> this does <em>not</em> requeue the message:
+     * failed messages will simply be dropped.  This is to prevent infinite
+     * redelivery in the event of non-transient failures (e.g. malformed
+     * messages).  However it means that messages will <em>not</em> be retried
+     * in the event of transient failures.</p>
+     */
     @Override
     public void fail(Object msgId) {
         if (msgId instanceof Long) {
@@ -178,6 +198,13 @@ public void fail(Object msgId) {
     }
 
 
+    /**
+     * Emits the next message from the queue as a tuple.
+     *
+     * <p>If no message is ready to emit, this will wait a short time
+     * ({@link #WAIT_FOR_NEXT_MESSAGE}) for one to arrive on the queue,
+     * to avoid a tight loop in the spout worker.</p>
+     */
     @Override
     public void nextTuple() {
         if (amqpConsumer != null) {
@@ -199,6 +226,10 @@ public void nextTuple() {
     }
 
 
+    /**
+     * Connects to the AMQP broker, declares the queue and subscribes to
+     * incoming messages.
+     */
     @Override
     public void open(@SuppressWarnings("rawtypes") Map config, TopologyContext context, SpoutOutputCollector collector) {
         Long prefetchCount = (Long) config.get(CONFIG_PREFETCH_COUNT);
@@ -243,6 +274,10 @@ private void setupAMQP(int prefetchCount) throws IOException {
     }
 
 
+    /**
+     * Declares the output fields of this spout according to the provided
+     * {@link backtype.storm.spout.Scheme}.
+     */
     @Override
     public void declareOutputFields(OutputFieldsDeclarer declarer) {
         declarer.declare(serialisationScheme.getOutputFields());