spring CompositeRequestCondition 源码

spring CompositeRequestCondition 代码

文件路径：/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/CompositeRequestCondition.java

/*
 * Copyright 2002-2021 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.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

import jakarta.servlet.http.HttpServletRequest;

import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;

/**
 * Implements the {@link RequestCondition} contract by delegating to multiple
 * {@code RequestCondition} types and using a logical conjunction ({@code ' && '}) to
 * ensure all conditions match a given request.
 *
 * <p>When {@code CompositeRequestCondition} instances are combined or compared
 * they are expected to (a) contain the same number of conditions and (b) that
 * conditions in the respective index are of the same type. It is acceptable to
 * provide {@code null} conditions or no conditions at all to the constructor.
 *
 * @author Rossen Stoyanchev
 * @since 3.2
 */
public class CompositeRequestCondition extends AbstractRequestCondition<CompositeRequestCondition> {

	private final RequestConditionHolder[] requestConditions;


	/**
	 * Create an instance with 0 or more {@code RequestCondition} types. It is
	 * important to create {@code CompositeRequestCondition} instances with the
	 * same number of conditions so they may be compared and combined.
	 * It is acceptable to provide {@code null} conditions.
	 */
	public CompositeRequestCondition(RequestCondition<?>... requestConditions) {
		this.requestConditions = wrap(requestConditions);
	}

	private CompositeRequestCondition(RequestConditionHolder[] requestConditions) {
		this.requestConditions = requestConditions;
	}


	private RequestConditionHolder[] wrap(RequestCondition<?>... rawConditions) {
		RequestConditionHolder[] wrappedConditions = new RequestConditionHolder[rawConditions.length];
		for (int i = 0; i < rawConditions.length; i++) {
			wrappedConditions[i] = new RequestConditionHolder(rawConditions[i]);
		}
		return wrappedConditions;
	}

	/**
	 * Whether this instance contains 0 conditions or not.
	 */
	@Override
	public boolean isEmpty() {
		return ObjectUtils.isEmpty(this.requestConditions);
	}

	/**
	 * Return the underlying conditions (possibly empty but never {@code null}).
	 */
	public List<RequestCondition<?>> getConditions() {
		return unwrap();
	}

	private List<RequestCondition<?>> unwrap() {
		List<RequestCondition<?>> result = new ArrayList<>();
		for (RequestConditionHolder holder : this.requestConditions) {
			result.add(holder.getCondition());
		}
		return result;
	}

	@Override
	protected Collection<?> getContent() {
		return (!isEmpty() ? getConditions() : Collections.emptyList());
	}

	@Override
	protected String getToStringInfix() {
		return " && ";
	}

	private int getLength() {
		return this.requestConditions.length;
	}

	/**
	 * If one instance is empty, return the other.
	 * If both instances have conditions, combine the individual conditions
	 * after ensuring they are of the same type and number.
	 */
	@Override
	public CompositeRequestCondition combine(CompositeRequestCondition other) {
		if (isEmpty() && other.isEmpty()) {
			return this;
		}
		else if (other.isEmpty()) {
			return this;
		}
		else if (isEmpty()) {
			return other;
		}
		else {
			assertNumberOfConditions(other);
			RequestConditionHolder[] combinedConditions = new RequestConditionHolder[getLength()];
			for (int i = 0; i < getLength(); i++) {
				combinedConditions[i] = this.requestConditions[i].combine(other.requestConditions[i]);
			}
			return new CompositeRequestCondition(combinedConditions);
		}
	}

	private void assertNumberOfConditions(CompositeRequestCondition other) {
		Assert.isTrue(getLength() == other.getLength(),
				"Cannot combine CompositeRequestConditions with a different number of conditions. " +
				ObjectUtils.nullSafeToString(this.requestConditions) + " and  " +
				ObjectUtils.nullSafeToString(other.requestConditions));
	}

	/**
	 * Delegate to <em>all</em> contained conditions to match the request and return the
	 * resulting "matching" condition instances.
	 * <p>An empty {@code CompositeRequestCondition} matches to all requests.
	 */
	@Override
	@Nullable
	public CompositeRequestCondition getMatchingCondition(HttpServletRequest request) {
		if (isEmpty()) {
			return this;
		}
		RequestConditionHolder[] matchingConditions = new RequestConditionHolder[getLength()];
		for (int i = 0; i < getLength(); i++) {
			matchingConditions[i] = this.requestConditions[i].getMatchingCondition(request);
			if (matchingConditions[i] == null) {
				return null;
			}
		}
		return new CompositeRequestCondition(matchingConditions);
	}

	/**
	 * If one instance is empty, the other "wins". If both instances have
	 * conditions, compare them in the order in which they were provided.
	 */
	@Override
	public int compareTo(CompositeRequestCondition other, HttpServletRequest request) {
		if (isEmpty() && other.isEmpty()) {
			return 0;
		}
		else if (isEmpty()) {
			return 1;
		}
		else if (other.isEmpty()) {
			return -1;
		}
		else {
			assertNumberOfConditions(other);
			for (int i = 0; i < getLength(); i++) {
				int result = this.requestConditions[i].compareTo(other.requestConditions[i], request);
				if (result != 0) {
					return result;
				}
			}
			return 0;
		}
	}

}

相关信息

spring 源码目录

相关文章

spring AbstractMediaTypeExpression 源码

spring AbstractNameValueExpression 源码

spring AbstractRequestCondition 源码

spring ConsumesRequestCondition 源码

spring HeadersRequestCondition 源码

spring MediaTypeExpression 源码

spring NameValueExpression 源码

spring ParamsRequestCondition 源码

spring PathPatternsRequestCondition 源码

spring PatternsRequestCondition 源码