com.wl4g.component.common.remoting.AbstractAsyncClientHttpRequest Maven / Gradle / Ivy
/*
* Copyright 2017 ~ 2025 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
*
* http://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 com.wl4g.component.common.remoting;
import java.io.IOException;
import java.io.OutputStream;
import com.google.common.util.concurrent.ListenableFuture;
import com.wl4g.component.common.lang.Assert2;
import com.wl4g.component.common.remoting.parse.HttpOutputMessage;
import com.wl4g.component.common.remoting.standard.HttpHeaders;
/**
* Abstract base for {@link AsyncClientHttpRequest} that makes sure that headers
* and body are not written multiple times.
* Represents a client-side asynchronous HTTP request. Created via an
* implementation of the {@link AsyncClientHttpRequestFactory}.
*
*
* A {@code AsyncHttpRequest} can be {@linkplain #executeAsync() executed},
* getting a future {@link ClientHttpResponse} which can be read from.
*
* @see AsyncClientHttpRequestFactory#createAsyncRequest
*/
abstract class AbstractAsyncClientHttpRequest implements HttpRequest, HttpOutputMessage {
private final HttpHeaders headers = new HttpHeaders();
private boolean executed = false;
@Override
public final HttpHeaders getHeaders() {
return (this.executed ? HttpHeaders.readOnlyHttpHeaders(headers) : headers);
}
@Override
public final OutputStream getBody() throws IOException {
assert2NotExecuted();
return getBodyInternal(headers);
}
/**
* Execute this request asynchronously, resulting in a Future handle.
* {@link ClientHttpResponse} that can be read.
*
* @return the future response result of the execution
* @throws java.io.IOException
* in case of I/O errors
*/
public ListenableFuture executeAsync() throws IOException {
assert2NotExecuted();
ListenableFuture result = executeInternal(headers);
this.executed = true;
return result;
}
/**
* Assert2s that this request has not been {@linkplain #executeAsync()
* executed} yet.
*
* @throws IllegalStateException
* if this request has been executed
*/
protected void assert2NotExecuted() {
Assert2.state(!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 ListenableFuture executeInternal(HttpHeaders headers) throws IOException;
}