/*
 * 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.http.client.support;

import java.io.IOException;
import java.net.URI;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.logging.Log;

import org.springframework.core.annotation.AnnotationAwareOrderComparator;
import org.springframework.http.HttpLogging;
import org.springframework.http.HttpMethod;
import org.springframework.http.client.ClientHttpRequest;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.ClientHttpRequestInitializer;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.util.Assert;

Base class for RestTemplate and other HTTP accessing gateway helpers, defining common properties such as the ClientHttpRequestFactory to operate on. 
Not intended to be used directly.
See RestTemplate for an entry point. 
Author:
Arjen Poutsma, Juergen Hoeller, Phillip Webb
See Also:
ClientHttpRequestFactory
RestTemplate
Since:
3.0/**
 * Base class for {@link org.springframework.web.client.RestTemplate}
 * and other HTTP accessing gateway helpers, defining common properties
 * such as the {@link ClientHttpRequestFactory} to operate on.
 *
 * <p>Not intended to be used directly.
 *
 * <p>See {@link org.springframework.web.client.RestTemplate} for an entry point.
 *
 * @author Arjen Poutsma
 * @author Juergen Hoeller
 * @author Phillip Webb
 * @since 3.0
 * @see ClientHttpRequestFactory
 * @see org.springframework.web.client.RestTemplate
 */
public abstract class HttpAccessor {

	
Logger available to subclasses. /** Logger available to subclasses. */
	protected final Log logger = HttpLogging.forLogName(getClass());

	private ClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();

	private final List<ClientHttpRequestInitializer> clientHttpRequestInitializers = new ArrayList<>();


	
Set the request factory that this accessor uses for obtaining client request handles.
The default is a SimpleClientHttpRequestFactory based on the JDK's own HTTP libraries (HttpURLConnection). 
Note that the standard JDK HTTP library does not support the HTTP PATCH method.
Configure the Apache HttpComponents or OkHttp request factory to enable PATCH.
See Also:
createRequest(URI, HttpMethod)
SimpleClientHttpRequestFactory
HttpComponentsAsyncClientHttpRequestFactory
OkHttp3ClientHttpRequestFactory/**
	 * Set the request factory that this accessor uses for obtaining client request handles.
	 * <p>The default is a {@link SimpleClientHttpRequestFactory} based on the JDK's own
	 * HTTP libraries ({@link java.net.HttpURLConnection}).
	 * <p><b>Note that the standard JDK HTTP library does not support the HTTP PATCH method.
	 * Configure the Apache HttpComponents or OkHttp request factory to enable PATCH.</b>
	 * @see #createRequest(URI, HttpMethod)
	 * @see SimpleClientHttpRequestFactory
	 * @see org.springframework.http.client.HttpComponentsAsyncClientHttpRequestFactory
	 * @see org.springframework.http.client.OkHttp3ClientHttpRequestFactory
	 */
	public void setRequestFactory(ClientHttpRequestFactory requestFactory) {
		Assert.notNull(requestFactory, "ClientHttpRequestFactory must not be null");
		this.requestFactory = requestFactory;
	}

	
Return the request factory that this accessor uses for obtaining client request handles.
/**
	 * Return the request factory that this accessor uses for obtaining client request handles.
	 */
	public ClientHttpRequestFactory getRequestFactory() {
		return this.requestFactory;
	}


	
Set the request initializers that this accessor should use.
The initializers will get immediately sorted according to their order. 
Since:
5.2/**
	 * Set the request initializers that this accessor should use.
	 * <p>The initializers will get immediately sorted according to their
	 * {@linkplain AnnotationAwareOrderComparator#sort(List) order}.
	 * @since 5.2
	 */
	public void setClientHttpRequestInitializers(
			List<ClientHttpRequestInitializer> clientHttpRequestInitializers) {

		if (this.clientHttpRequestInitializers != clientHttpRequestInitializers) {
			this.clientHttpRequestInitializers.clear();
			this.clientHttpRequestInitializers.addAll(clientHttpRequestInitializers);
			AnnotationAwareOrderComparator.sort(this.clientHttpRequestInitializers);
		}
	}

	
Get the request initializers that this accessor uses.
The returned List is active and may be modified. Note, however, that the initializers will not be resorted according to their order before the ClientHttpRequest is initialized. 
See Also:
setClientHttpRequestInitializers(List<ClientHttpRequestInitializer>)
Since:
5.2/**
	 * Get the request initializers that this accessor uses.
	 * <p>The returned {@link List} is active and may be modified. Note,
	 * however, that the initializers will not be resorted according to their
	 * {@linkplain AnnotationAwareOrderComparator#sort(List) order} before the
	 * {@link ClientHttpRequest} is initialized.
	 * @since 5.2
	 * @see #setClientHttpRequestInitializers(List)
	 */
	public List<ClientHttpRequestInitializer> getClientHttpRequestInitializers() {
		return this.clientHttpRequestInitializers;
	}

	
Create a new ClientHttpRequest via this template's ClientHttpRequestFactory. 
Params:
url – the URL to connect to
method – the HTTP method to execute (GET, POST, etc)
Throws:
IOException – in case of I/O errors
See Also:
getRequestFactory()
ClientHttpRequestFactory.createRequest(URI, HttpMethod)
Returns:
the created request/**
	 * Create a new {@link ClientHttpRequest} via this template's {@link ClientHttpRequestFactory}.
	 * @param url the URL to connect to
	 * @param method the HTTP method to execute (GET, POST, etc)
	 * @return the created request
	 * @throws IOException in case of I/O errors
	 * @see #getRequestFactory()
	 * @see ClientHttpRequestFactory#createRequest(URI, HttpMethod)
	 */
	protected ClientHttpRequest createRequest(URI url, HttpMethod method) throws IOException {
		ClientHttpRequest request = getRequestFactory().createRequest(url, method);
		initialize(request);
		if (logger.isDebugEnabled()) {
			logger.debug("HTTP " + method.name() + " " + url);
		}
		return request;
	}

	private void initialize(ClientHttpRequest request) {
		this.clientHttpRequestInitializers.forEach(initializer -> initializer.initialize(request));
	}

}