Java tutorial
/* * Copyright 2002-2019 the original author or authors. * * 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 * * https://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.springframework.integration.channel; import java.util.List; import org.springframework.integration.core.MessageSelector; import org.springframework.lang.Nullable; import org.springframework.messaging.Message; /** * Operations available on a channel that has queuing semantics. * * @author Gary Russell * @author Artem Bilan * * @since 3.0 * */ public interface QueueChannelOperations { /** * Remove all {@link Message Messages} from this channel. * @return The messages that were removed. */ List<Message<?>> clear(); /** * Remove any {@link Message Messages} that are not accepted by the provided selector. * @param selector The message selector. * @return The list of messages that were purged. */ List<Message<?>> purge(@Nullable MessageSelector selector); /** * Obtain the current number of queued {@link Message Messages} in this channel. * @return The current number of queued {@link Message Messages} in this channel. */ int getQueueSize(); /** * Obtain the remaining capacity of this channel. * @return The remaining capacity of this channel. */ int getRemainingCapacity(); }