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.core; import org.springframework.lang.Nullable; import org.springframework.messaging.Message; /** * Base interface for any source of {@link Message Messages} that can be polled. * * @author Mark Fisher */ @FunctionalInterface public interface MessageSource<T> { /** * Retrieve the next available message from this source. * Returns <code>null</code> if no message is available. * @return The message or null. */ @Nullable Message<T> receive(); }