added Poison Pill idiom

poison-pill/src/main/java/com/iluwatar/Message.java

@@ -0,0 +1,52 @@
+package com.iluwatar;
+
+import java.util.Map;
+
+/**
+ * Interface that implements the Message pattern and represents an inbound or outbound message as part of an {@link Producer}-{@link Consumer} exchange.
+ */
+public interface Message {
+
+	public static final Message POISON_PILL = new Message() {
+
+		@Override
+		public void addHeader(Headers header, String value) {
+			throw poison();
+		}
+
+		@Override
+		public String getHeader(Headers header) {
+			throw poison();
+		}
+
+		@Override
+		public Map<Headers, String> getHeaders() {
+			throw poison();
+		}
+
+		@Override
+		public void setBody(String body) {
+			throw poison();
+		}
+
+		@Override
+		public String getBody() {
+			throw poison();
+		}
+
+		private RuntimeException poison() {
+			return new UnsupportedOperationException("Poison");
+		}
+
+	};
+
+	public enum Headers {
+		DATE, SENDER
+	}
+
+	public void addHeader(Headers header, String value);
+	public String getHeader(Headers header);
+	public Map<Headers, String> getHeaders();
+	public void setBody(String body);
+	public String getBody();
+}