HttpComponentsHttpInvokerRequestExecutor (Spring Framework 3.2.1.RELEASE API)
Date: 2013-01-24

org.springframework.remoting.httpinvoker

## Class HttpComponentsHttpInvokerRequestExecutor

- java.lang.Object
- - org.springframework.remoting.httpinvoker.AbstractHttpInvokerRequestExecutor
  - - org.springframework.remoting.httpinvoker.HttpComponentsHttpInvokerRequestExecutor

- All Implemented Interfaces:
    Aware, BeanClassLoaderAware, HttpInvokerRequestExecutor

      public class HttpComponentsHttpInvokerRequestExecutor
      extends AbstractHttpInvokerRequestExecutor

  `HttpInvokerRequestExecutor` implementation that uses Apache HttpComponents HttpClient to execute POST requests.

  Allows to use a pre-configured `HttpClient` instance, potentially with authentication, HTTP connection pooling, etc. Also designed for easy subclassing, providing specific template methods.

  As of Spring 3.2, this request executor requires Apache HttpComponents 4.2 or higher.

  Since:
    3.1
  Author:
    Juergen Hoeller
  See Also:
    `SimpleHttpInvokerRequestExecutor`

- - ### Field Summary

    - ### Fields inherited from class org.springframework.remoting.httpinvoker.AbstractHttpInvokerRequestExecutor

      `CONTENT_TYPE_SERIALIZED_OBJECT, ENCODING_GZIP, HTTP_HEADER_ACCEPT_ENCODING, HTTP_HEADER_ACCEPT_LANGUAGE, HTTP_HEADER_CONTENT_ENCODING, HTTP_HEADER_CONTENT_LENGTH, HTTP_HEADER_CONTENT_TYPE, HTTP_METHOD_POST, logger`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `HttpComponentsHttpInvokerRequestExecutor()` Create a new instance of the HttpComponentsHttpInvokerRequestExecutor with a default `HttpClient` that uses a default `PoolingClientConnectionManager`.
    `HttpComponentsHttpInvokerRequestExecutor(org.apache.http.client.HttpClient httpClient)` Create a new instance of the HttpComponentsClientHttpRequestFactory with the given `HttpClient` instance.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `protected org.apache.http.client.methods.HttpPost` | `createHttpPost(HttpInvokerClientConfiguration config)` Create a HttpPost for the given configuration.
    `protected RemoteInvocationResult` | `doExecuteRequest(HttpInvokerClientConfiguration config, ByteArrayOutputStream baos)` Execute the given request through the HttpClient.
    `protected org.apache.http.HttpResponse` | `executeHttpPost(HttpInvokerClientConfiguration config, org.apache.http.client.HttpClient httpClient, org.apache.http.client.methods.HttpPost httpPost)` Execute the given HttpPost instance.
    `org.apache.http.client.HttpClient` | `getHttpClient()` Return the `HttpClient` instance that this request executor uses.
    `protected InputStream` | `getResponseBody(HttpInvokerClientConfiguration config, org.apache.http.HttpResponse httpResponse)` Extract the response body from the given executed remote invocation request.
    `protected boolean` | `isGzipResponse(org.apache.http.HttpResponse httpResponse)` Determine whether the given response indicates a GZIP response.
    `void` | `setConnectTimeout(int timeout)` Set the connection timeout for the underlying HttpClient.
    `void` | `setHttpClient(org.apache.http.client.HttpClient httpClient)` Set the `HttpClient` instance to use for this request executor.
    `void` | `setReadTimeout(int timeout)` Set the socket read timeout for the underlying HttpClient.
    `protected void` | `setRequestBody(HttpInvokerClientConfiguration config, org.apache.http.client.methods.HttpPost httpPost, ByteArrayOutputStream baos)` Set the given serialized remote invocation as request body.
    `protected void` | `validateResponse(HttpInvokerClientConfiguration config, org.apache.http.HttpResponse response)` Validate the given response as contained in the HttpPost object, throwing an exception if it does not correspond to a successful HTTP response.

    - ### Methods inherited from class org.springframework.remoting.httpinvoker.AbstractHttpInvokerRequestExecutor

      `createObjectInputStream, decorateInputStream, decorateOutputStream, doReadRemoteInvocationResult, doWriteRemoteInvocation, executeRequest, getBeanClassLoader, getByteArrayOutputStream, getContentType, isAcceptGzipEncoding, readRemoteInvocationResult, setAcceptGzipEncoding, setBeanClassLoader, setContentType, writeRemoteInvocation`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### HttpComponentsHttpInvokerRequestExecutor

          public HttpComponentsHttpInvokerRequestExecutor()

      Create a new instance of the HttpComponentsHttpInvokerRequestExecutor with a default `HttpClient` that uses a default `PoolingClientConnectionManager`.

    - #### HttpComponentsHttpInvokerRequestExecutor

          public HttpComponentsHttpInvokerRequestExecutor(org.apache.http.client.HttpClient httpClient)

      Create a new instance of the HttpComponentsClientHttpRequestFactory with the given `HttpClient` instance.
      Parameters:
        `httpClient` - the HttpClient instance to use for this request executor

  - ### Method Detail

    - #### setHttpClient

          public void setHttpClient(org.apache.http.client.HttpClient httpClient)

      Set the `HttpClient` instance to use for this request executor.

    - #### getHttpClient

          public org.apache.http.client.HttpClient getHttpClient()

      Return the `HttpClient` instance that this request executor uses.

    - #### setConnectTimeout

          public void setConnectTimeout(int timeout)

      Set the connection timeout for the underlying HttpClient. A timeout value of 0 specifies an infinite timeout.
      Parameters:
        `timeout` - the timeout value in milliseconds

    - #### setReadTimeout

          public void setReadTimeout(int timeout)

      Set the socket read timeout for the underlying HttpClient. A timeout value of 0 specifies an infinite timeout.
      Parameters:
        `timeout` - the timeout value in milliseconds
      See Also:
        `DEFAULT_READ_TIMEOUT_MILLISECONDS`

    - #### doExecuteRequest

          protected RemoteInvocationResult doExecuteRequest(HttpInvokerClientConfiguration config,
                                                ByteArrayOutputStream baos)
                                                     throws IOException,
                                                            ClassNotFoundException

      Execute the given request through the HttpClient.

      This method implements the basic processing workflow: The actual work happens in this class's template methods.

      Specified by:
        `doExecuteRequest` in class `AbstractHttpInvokerRequestExecutor`
      Parameters:
        `config` - the HTTP invoker configuration that specifies the target service
        `baos` - the ByteArrayOutputStream that contains the serialized RemoteInvocation object
      Returns:
        the RemoteInvocationResult object
      Throws:
        `IOException` - if thrown by I/O operations
        `ClassNotFoundException` - if thrown during deserialization
      See Also:
        `createHttpPost(org.springframework.remoting.httpinvoker.HttpInvokerClientConfiguration)`, `setRequestBody(org.springframework.remoting.httpinvoker.HttpInvokerClientConfiguration, org.apache.http.client.methods.HttpPost, java.io.ByteArrayOutputStream)`, `executeHttpPost(org.springframework.remoting.httpinvoker.HttpInvokerClientConfiguration, org.apache.http.client.HttpClient, org.apache.http.client.methods.HttpPost)`, `validateResponse(org.springframework.remoting.httpinvoker.HttpInvokerClientConfiguration, org.apache.http.HttpResponse)`, `getResponseBody(org.springframework.remoting.httpinvoker.HttpInvokerClientConfiguration, org.apache.http.HttpResponse)`

    - #### createHttpPost

          protected org.apache.http.client.methods.HttpPost createHttpPost(HttpInvokerClientConfiguration config)
                                                                    throws IOException

      Create a HttpPost for the given configuration.

      The default implementation creates a standard HttpPost with "application/x-java-serialized-object" as "Content-Type" header.

      Parameters:
        `config` - the HTTP invoker configuration that specifies the target service
      Returns:
        the HttpPost instance
      Throws:
        `IOException` - if thrown by I/O methods

    - #### setRequestBody

          protected void setRequestBody(HttpInvokerClientConfiguration config,
                            org.apache.http.client.methods.HttpPost httpPost,
                            ByteArrayOutputStream baos)
                                 throws IOException

      Set the given serialized remote invocation as request body.

      The default implementation simply sets the serialized invocation as the HttpPost's request body. This can be overridden, for example, to write a specific encoding and to potentially set appropriate HTTP request headers.

      Parameters:
        `config` - the HTTP invoker configuration that specifies the target service
        `httpPost` - the HttpPost to set the request body on
        `baos` - the ByteArrayOutputStream that contains the serialized RemoteInvocation object
      Throws:
        `IOException` - if thrown by I/O methods

    - #### executeHttpPost

          protected org.apache.http.HttpResponse executeHttpPost(HttpInvokerClientConfiguration config,
                                                     org.apache.http.client.HttpClient httpClient,
                                                     org.apache.http.client.methods.HttpPost httpPost)
                                                          throws IOException

      Execute the given HttpPost instance.
      Parameters:
        `config` - the HTTP invoker configuration that specifies the target service
        `httpClient` - the HttpClient to execute on
        `httpPost` - the HttpPost to execute
      Returns:
        the resulting HttpResponse
      Throws:
        `IOException` - if thrown by I/O methods

    - #### validateResponse

          protected void validateResponse(HttpInvokerClientConfiguration config,
                              org.apache.http.HttpResponse response)
                                   throws IOException

      Validate the given response as contained in the HttpPost object, throwing an exception if it does not correspond to a successful HTTP response.

      Default implementation rejects any HTTP status code beyond 2xx, to avoid parsing the response body and trying to deserialize from a corrupted stream.

      Parameters:
        `config` - the HTTP invoker configuration that specifies the target service
        `response` - the resulting HttpResponse to validate
      Throws:
        `IOException` - if validation failed

    - #### getResponseBody

          protected InputStream getResponseBody(HttpInvokerClientConfiguration config,
                                    org.apache.http.HttpResponse httpResponse)
                                         throws IOException

      Extract the response body from the given executed remote invocation request.

      The default implementation simply fetches the HttpPost's response body stream. If the response is recognized as GZIP response, the InputStream will get wrapped in a GZIPInputStream.

      Parameters:
        `config` - the HTTP invoker configuration that specifies the target service
        `httpResponse` - the resulting HttpResponse to read the response body from
      Returns:
        an InputStream for the response body
      Throws:
        `IOException` - if thrown by I/O methods
      See Also:
        `isGzipResponse(org.apache.http.HttpResponse)`, `GZIPInputStream`

    - #### isGzipResponse

          protected boolean isGzipResponse(org.apache.http.HttpResponse httpResponse)

      Determine whether the given response indicates a GZIP response.

      The default implementation checks whether the HTTP "Content-Encoding" header contains "gzip" (in any casing).

      Parameters:
        `httpResponse` - the resulting HttpResponse to check
      Returns:
        whether the given response indicates a GZIP response