org.springframework.http.client.AbstractClientHttpRequest Maven / Gradle / Ivy
/*
* 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;
import java.io.IOException;
import java.io.OutputStream;
import org.springframework.http.HttpHeaders;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
/**
* Abstract base for {@link ClientHttpRequest} that makes sure that headers
* and body are not written multiple times.
*
* @author Arjen Poutsma
* @since 3.0
*/
public abstract class AbstractClientHttpRequest implements ClientHttpRequest {
private final HttpHeaders headers = new HttpHeaders();
private boolean executed = false;
@Nullable
private HttpHeaders readOnlyHeaders;
@Override
public final HttpHeaders getHeaders() {
if (this.readOnlyHeaders != null) {
return this.readOnlyHeaders;
}
else if (this.executed) {
this.readOnlyHeaders = HttpHeaders.readOnlyHttpHeaders(this.headers);
return this.readOnlyHeaders;
}
else {
return this.headers;
}
}
@Override
public final OutputStream getBody() throws IOException {
assertNotExecuted();
return getBodyInternal(this.headers);
}
@Override
public final ClientHttpResponse execute() throws IOException {
assertNotExecuted();
ClientHttpResponse result = executeInternal(this.headers);
this.executed = true;
return result;
}
/**
* Assert that this request has not been {@linkplain #execute() executed} yet.
* @throws IllegalStateException if this request has been executed
*/
protected void assertNotExecuted() {
Assert.state(!this.executed, "ClientHttpRequest already executed");
}
/**
* Abstract template method that returns the body.
* @param headers the HTTP headers
* @return the body output stream
*/
protected abstract OutputStream getBodyInternal(HttpHeaders headers) throws IOException;
/**
* Abstract template method that writes the given headers and content to the HTTP request.
* @param headers the HTTP headers
* @return the response object for the executed request
*/
protected abstract ClientHttpResponse executeInternal(HttpHeaders headers) throws IOException;
}