001/* 002 * Copyright 2002-2013 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.messaging; 018 019/** 020 * A {@link MessageChannel} from which messages may be actively received through polling. 021 * 022 * @author Mark Fisher 023 * @since 4.0 024 */ 025public interface PollableChannel extends MessageChannel { 026 027 /** 028 * Receive a message from this channel, blocking indefinitely if necessary. 029 * @return the next available {@link Message} or {@code null} if interrupted 030 */ 031 Message<?> receive(); 032 033 /** 034 * Receive a message from this channel, blocking until either a message is available 035 * or the specified timeout period elapses. 036 * @param timeout the timeout in milliseconds or {@link MessageChannel#INDEFINITE_TIMEOUT}. 037 * @return the next available {@link Message} or {@code null} if the specified timeout 038 * period elapses or the message reception is interrupted 039 */ 040 Message<?> receive(long timeout); 041 042}