001/* 002 * Copyright 2002-2015 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.context; 018 019import org.springframework.core.ResolvableType; 020import org.springframework.core.ResolvableTypeProvider; 021import org.springframework.util.Assert; 022 023/** 024 * An {@link ApplicationEvent} that carries an arbitrary payload. 025 * 026 * <p>Mainly intended for internal use within the framework. 027 * 028 * @author Stephane Nicoll 029 * @since 4.2 030 * @param <T> the payload type of the event 031 */ 032@SuppressWarnings("serial") 033public class PayloadApplicationEvent<T> extends ApplicationEvent implements ResolvableTypeProvider { 034 035 private final T payload; 036 037 038 /** 039 * Create a new PayloadApplicationEvent. 040 * @param source the object on which the event initially occurred (never {@code null}) 041 * @param payload the payload object (never {@code null}) 042 */ 043 public PayloadApplicationEvent(Object source, T payload) { 044 super(source); 045 Assert.notNull(payload, "Payload must not be null"); 046 this.payload = payload; 047 } 048 049 050 @Override 051 public ResolvableType getResolvableType() { 052 return ResolvableType.forClassWithGenerics(getClass(), ResolvableType.forInstance(getPayload())); 053 } 054 055 /** 056 * Return the payload of the event. 057 */ 058 public T getPayload() { 059 return this.payload; 060 } 061 062}