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.web.servlet.mvc.condition; import java.util.Collection; import java.util.StringJoiner; import org.springframework.lang.Nullable; /** * A base class for {@link RequestCondition} types providing implementations of * {@link #equals(Object)}, {@link #hashCode()}, and {@link #toString()}. * * @author Rossen Stoyanchev * @since 3.1 * @param <T> the type of objects that this RequestCondition can be combined * with and compared to */ public abstract class AbstractRequestCondition<T extends AbstractRequestCondition<T>> implements RequestCondition<T> { /** * Indicates whether this condition is empty, i.e. whether or not it * contains any discrete items. * @return {@code true} if empty; {@code false} otherwise */ public boolean isEmpty() { return getContent().isEmpty(); } /** * Return the discrete items a request condition is composed of. * <p>For example URL patterns, HTTP request methods, param expressions, etc. * @return a collection of objects (never {@code null}) */ protected abstract Collection<?> getContent(); /** * The notation to use when printing discrete items of content. * <p>For example {@code " || "} for URL patterns or {@code " && "} * for param expressions. */ protected abstract String getToStringInfix(); @Override public boolean equals(@Nullable Object other) { if (this == other) { return true; } if (other == null || getClass() != other.getClass()) { return false; } return getContent().equals(((AbstractRequestCondition<?>) other).getContent()); } @Override public int hashCode() { return getContent().hashCode(); } @Override public String toString() { String infix = getToStringInfix(); StringJoiner joiner = new StringJoiner(infix, "[", "]"); for (Object expression : getContent()) { joiner.add(expression.toString()); } return joiner.toString(); } }