/*
* Copyright (C) 2011 Red Hat, Inc. and/or its affiliates.
*
* 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.jboss.errai.bus.client.api.messaging;
// TODO create tests for usage of this interface
/**
* Callback interface for observing every message on the bus before that message
* is sent to any {@link MessageCallback message callbacks}. A MessageListener
* can cancel delivery of a message.
* <p>
* If your goal is to implement security policies around messages to a
* particular subject, {@link org.jboss.errai.bus.client.api.BooleanRoutingRule} is a better choice than
* MessageListener.
*/
public interface MessageListener {
/**
* Called by the Message Bus before the given message is routed to any
* MessageListeners.
*
* @param message
* The message being processed by the bus.
* @return true if delivery of {@code message} should be allowed to proceed;
* false if {@code message} must not be delivered.
*/
public boolean handleMessage(Message message);
}