/*
 * Copyright 2002-2020 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.http.client.support;

import java.util.ArrayList;
import java.util.List;

import org.springframework.core.annotation.AnnotationAwareOrderComparator;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.ClientHttpRequestInterceptor;
import org.springframework.http.client.InterceptingClientHttpRequestFactory;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;

Base class for RestTemplate and other HTTP accessing gateway helpers, adding interceptor-related properties to HttpAccessor's common properties. 
Not intended to be used directly. See RestTemplate for an entry point. 
Author:
Arjen Poutsma, Juergen Hoeller
See Also:
ClientHttpRequestInterceptor
InterceptingClientHttpRequestFactory
RestTemplate
Since:
3.0/**
 * Base class for {@link org.springframework.web.client.RestTemplate}
 * and other HTTP accessing gateway helpers, adding interceptor-related
 * properties to {@link HttpAccessor}'s common properties.
 *
 * <p>Not intended to be used directly.
 * See {@link org.springframework.web.client.RestTemplate} for an entry point.
 *
 * @author Arjen Poutsma
 * @author Juergen Hoeller
 * @since 3.0
 * @see ClientHttpRequestInterceptor
 * @see InterceptingClientHttpRequestFactory
 * @see org.springframework.web.client.RestTemplate
 */
public abstract class InterceptingHttpAccessor extends HttpAccessor {

	private final List<ClientHttpRequestInterceptor> interceptors = new ArrayList<>();

	@Nullable
	private volatile ClientHttpRequestFactory interceptingRequestFactory;


	
Set the request interceptors that this accessor should use.
The interceptors will get immediately sorted according to their order. 
See Also:
getRequestFactory()
AnnotationAwareOrderComparator/**
	 * Set the request interceptors that this accessor should use.
	 * <p>The interceptors will get immediately sorted according to their
	 * {@linkplain AnnotationAwareOrderComparator#sort(List) order}.
	 * @see #getRequestFactory()
	 * @see AnnotationAwareOrderComparator
	 */
	public void setInterceptors(List<ClientHttpRequestInterceptor> interceptors) {
		Assert.noNullElements(interceptors, "'interceptors' must not contain null elements");
		// Take getInterceptors() List as-is when passed in here
		if (this.interceptors != interceptors) {
			this.interceptors.clear();
			this.interceptors.addAll(interceptors);
			AnnotationAwareOrderComparator.sort(this.interceptors);
		}
	}

	
Get the request interceptors that this accessor uses.
The returned List is active and may be modified. Note, however, that the interceptors will not be resorted according to their order before the ClientHttpRequestFactory is built. /**
	 * Get the request interceptors that this accessor uses.
	 * <p>The returned {@link List} is active and may be modified. Note,
	 * however, that the interceptors will not be resorted according to their
	 * {@linkplain AnnotationAwareOrderComparator#sort(List) order} before the
	 * {@link ClientHttpRequestFactory} is built.
	 */
	public List<ClientHttpRequestInterceptor> getInterceptors() {
		return this.interceptors;
	}

	
{@inheritDoc}
/**
	 * {@inheritDoc}
	 */
	@Override
	public void setRequestFactory(ClientHttpRequestFactory requestFactory) {
		super.setRequestFactory(requestFactory);
		this.interceptingRequestFactory = null;
	}

	
Overridden to expose an InterceptingClientHttpRequestFactory if necessary. 
See Also:
getInterceptors()/**
	 * Overridden to expose an {@link InterceptingClientHttpRequestFactory}
	 * if necessary.
	 * @see #getInterceptors()
	 */
	@Override
	public ClientHttpRequestFactory getRequestFactory() {
		List<ClientHttpRequestInterceptor> interceptors = getInterceptors();
		if (!CollectionUtils.isEmpty(interceptors)) {
			ClientHttpRequestFactory factory = this.interceptingRequestFactory;
			if (factory == null) {
				factory = new InterceptingClientHttpRequestFactory(super.getRequestFactory(), interceptors);
				this.interceptingRequestFactory = factory;
			}
			return factory;
		}
		else {
			return super.getRequestFactory();
		}
	}

}