001/* 002 * Copyright 2002-2019 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.handler; 018 019import java.util.Collection; 020import java.util.StringJoiner; 021 022import org.springframework.lang.Nullable; 023 024/** 025 * Base class for {@code MessageCondition's} that pre-declares abstract methods 026 * {@link #getContent()} and {@link #getToStringInfix()} in order to provide 027 * implementations of {@link #equals(Object)}, {@link #hashCode()}, and 028 * {@link #toString()}. 029 * 030 * @author Rossen Stoyanchev 031 * @since 4.0 032 * @param <T> the kind of condition that this condition can be combined with or compared to 033 */ 034public abstract class AbstractMessageCondition<T extends AbstractMessageCondition<T>> implements MessageCondition<T> { 035 036 @Override 037 public boolean equals(@Nullable Object other) { 038 if (this == other) { 039 return true; 040 } 041 if (other == null || getClass() != other.getClass()) { 042 return false; 043 } 044 return getContent().equals(((AbstractMessageCondition<?>) other).getContent()); 045 } 046 047 @Override 048 public int hashCode() { 049 return getContent().hashCode(); 050 } 051 052 @Override 053 public String toString() { 054 StringJoiner joiner = new StringJoiner(getToStringInfix(), "[", "]"); 055 for (Object expression : getContent()) { 056 joiner.add(expression.toString()); 057 } 058 return joiner.toString(); 059 } 060 061 062 /** 063 * Return the collection of objects the message condition is composed of 064 * (e.g. destination patterns), never {@code null}. 065 */ 066 protected abstract Collection<?> getContent(); 067 068 /** 069 * The notation to use when printing discrete items of content. 070 * For example " || " for URL patterns or " && " for param expressions. 071 */ 072 protected abstract String getToStringInfix(); 073 074}