Add EmptyMessage class that was missing from previous commit.

src/com/google/bitcoin/core/EmptyMessage.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2011 Steve Coughlan.
+ *
+ * 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 com.google.bitcoin.core;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+/**
+ * Parent class for header only messages that don't have a payload.
+ * Currently this includes getaddr, ping, verack as well as the special bitcoinj class UnknownMessage
+ *
+ * @author Steve Coughlan
+ */
+public abstract class EmptyMessage extends Message {
+
+	public EmptyMessage() {
+	}
+
+	public EmptyMessage(NetworkParameters params) {
+		super(params);
+	}
+
+	public EmptyMessage(NetworkParameters params, byte[] msg, int offset) throws ProtocolException {
+		super(params, msg, offset);
+	}
+
+	@Override
+	final protected void bitcoinSerializeToStream(OutputStream stream) throws IOException {
+	}
+
+	@Override
+	int getMessageSize() {
+		return 0;
+	}
+
+	/* (non-Javadoc)
+	 * @see com.google.bitcoin.core.Message#parse()
+	 */
+	@Override
+	void parse() throws ProtocolException {
+	}
+}