Class ResponseEntity

  • All Implemented Interfaces:
    Message, Response, ResponseHeader, StatusLine

    class ResponseEntity
    extends ResponseMessage
    implements Response
    This is used to represent the HTTP response. This provides methods that can be used to set various characteristics of the response. The OutputStream of the Response can be retrieved from this interface as can the I.P address of the client that will be receiving the Response. The attributes of the connection can be retrieved also. This provides a set of methods that can be used to set the attributes of the stream so the Response can be transported properly. The headers can be set and will be sent once a commit is made, or when there is content sent over the output stream.

    This should never allow the message body be sent if it should not be sent with the headers as of RFC 2616 rules for the presence of a message body. A message body must not be included with a HEAD request or with a 304 or a 204 response. A proper implementation of this will prevent a message body being sent if the response is to a HEAD request of if there is a 304 or 204 response code.

    It is important to note that the Response controls the processing of the HTTP pipeline. The next HTTP request is not processed until the response has committed. The response is committed once the commit method is invoked if there is NO content body. Committing with a content body is done only if correct content is given. The OutputStream acts as a client and commits the response once the specified content has been written to the issued OutputStream.

    • Field Detail

      • observer

        private BodyObserver observer
        This is the observer that is used to monitor the response.
      • buffer

        private ResponseBuffer buffer
        This is used to buffer the bytes that are sent to the client.
      • support

        private Conversation support
        This is the conversation used to determine connection type.
      • channel

        private Channel channel
        This is the underlying channel for the connected pipeline.
      • sender

        private ByteWriter sender
        This is the sender object used to deliver to response data.
      • trace

        private Trace trace
        This is used to trace events that occur with the response
    • Constructor Detail

      • ResponseEntity

        public ResponseEntity​(BodyObserver observer,
                              Request request,
                              Entity entity)
        Constructor for the ResponseEntity object. This is used to create a response instance using the provided request, entity, and monitor object. To ensure that the response is compatible with client the Request is used. Also to ensure the next request can be processed the provided monitor is used to signal response events to the server kernel.
        Parameters:
        observer - this is the observer used to signal events
        request - this is the request that was sent by the client
        entity - this is the entity that contains the channel
    • Method Detail

      • getResponseTime

        public long getResponseTime()
        This represents the time at which the response has fully written. Because the response is delivered asynchronously to the client this response time does not represent the time to last byte. It simply represents the time at which the response has been fully generated and written to the output buffer or queue. This returns zero if the response has not finished.
        Specified by:
        getResponseTime in interface Response
        Returns:
        this is the time taken to complete the response
      • getAttribute

        public java.lang.Object getAttribute​(java.lang.Object name)
        This is used as a shortcut for acquiring attributes for the response. This avoids acquiring the Attributes in order to retrieve the attribute directly from that object. The attributes contain data specific to the response.
        Parameters:
        name - this is the name of the attribute to acquire
        Returns:
        this returns the attribute for the specified name
      • getAttributes

        public java.util.Map getAttributes()
        This can be used to retrieve certain attributes about this Response. The attributes contains certain properties about the Response. For example if this Response goes over a secure line then there may be any arbitrary attributes.
        Returns:
        the response attributes of that have been set
      • setContentLength

        public void setContentLength​(long length)
        This should be used when the size of the message body is known. For performance reasons this should be used so the length of the output is known. This ensures that Persistent HTTP (PHTTP) connections can be maintained for both HTTP/1.0 and HTTP/1.1 clients. If the length of the output is not known HTTP/1.0 clients will require a connection close, which reduces performance (see RFC 2616).

        This removes any previous Content-Length headers from the message header. This will then set the appropriate Content-Length header with the correct length. If a the Connection header is set with the close token then the semantics of the connection are such that the server will close it once the OutputStream.close is used.

        Specified by:
        setContentLength in interface Response
        Parameters:
        length - this is the length of the HTTP message body
      • setContentType

        public void setContentType​(java.lang.String type)
        This is used to set the content type for the response. Typically a response will contain a message body of some sort. This is used to conveniently set the type for that response. Setting the content type can also be done explicitly if desired.
        Specified by:
        setContentType in interface Response
        Parameters:
        type - this is the type that is to be set in the response
      • getCharset

        private java.lang.String getCharset()
        This determines the charset for PrintStream objects returned from the getPrintStream method. This will return a valid charset regardless of whether the Content-Type header has been set, set without a charset, or not set at all. If unspecified, the charset returned is ISO-8859-1, as suggested by RFC 2616, section 3.7.1.
        Returns:
        returns the charset used by this response object
      • getOutputStream

        public java.io.OutputStream getOutputStream()
                                             throws java.io.IOException
        Used to write a message body with the Response. The semantics of this OutputStream will be determined by the HTTP version of the client, and whether or not the content length has been set, through the setContentLength method. If the length of the output is not known then the output is chunked for HTTP/1.1 clients and closed for HTTP/1.0 clients.
        Specified by:
        getOutputStream in interface Response
        Returns:
        an output stream object used to write the message body
        Throws:
        java.io.IOException
      • getOutputStream

        public java.io.OutputStream getOutputStream​(int size)
                                             throws java.io.IOException
        Used to write a message body with the Response. The semantics of this OutputStream will be determined by the HTTP version of the client, and whether or not the content length has been set, through the setContentLength method. If the length of the output is not known then the output is chunked for HTTP/1.1 clients and closed for HTTP/1.0 clients.

        This will ensure that there is buffering done so that the output can be reset using the reset method. This will enable the specified number of bytes to be written without committing the response. This specified size is the minimum size that the response buffer must be.

        Specified by:
        getOutputStream in interface Response
        Parameters:
        size - the minimum size that the response buffer must be
        Returns:
        an output stream object used to write the message body
        Throws:
        java.io.IOException
      • getPrintStream

        public java.io.PrintStream getPrintStream()
                                           throws java.io.IOException
        This method is provided for convenience so that the HTTP content can be written using the print methods provided by the PrintStream. This will basically wrap the getOutputStream with a buffer size of zero.

        The retrieved PrintStream uses the charset used to describe the content, with the Content-Type header. This will check the charset parameter of the contents MIME type. So if the Content-Type was text/plain; charset=UTF-8 the resulting PrintStream would encode the written data using the UTF-8 encoding scheme. Care must be taken to ensure that bytes written to the stream are correctly encoded.

        Specified by:
        getPrintStream in interface Response
        Returns:
        a print stream object used to write the message body
        Throws:
        java.io.IOException
      • getPrintStream

        public java.io.PrintStream getPrintStream​(int size)
                                           throws java.io.IOException
        This method is provided for convenience so that the HTTP content can be written using the print methods provided by the PrintStream. This will basically wrap the getOutputStream with a specified buffer size.

        The retrieved PrintStream uses the charset used to describe the content, with the Content-Type header. This will check the charset parameter of the contents MIME type. So if the Content-Type was text/plain; charset=UTF-8 the resulting PrintStream would encode the written data using the UTF-8 encoding scheme. Care must be taken to ensure that bytes written to the stream are correctly encoded.

        Specified by:
        getPrintStream in interface Response
        Parameters:
        size - the minimum size that the response buffer must be
        Returns:
        a print stream object used to write the message body
        Throws:
        java.io.IOException
      • getPrintStream

        private java.io.PrintStream getPrintStream​(int size,
                                                   java.lang.String charset)
                                            throws java.io.IOException
        This is used to wrap the getOutputStream object in a PrintStream, which will write content using a specified charset. The PrintStream created will not buffer the content, it will write directly to the underlying OutputStream where it is buffered (if there is a buffer size greater than zero specified). In future the buffer of the PrintStream may be usable.
        Parameters:
        size - the minimum size that the response buffer must be
        charset - this is the charset used by the resulting stream
        Returns:
        a print stream that encodes in the given charset
        Throws:
        java.io.IOException
      • getByteChannel

        public java.nio.channels.WritableByteChannel getByteChannel()
                                                             throws java.io.IOException
        Used to write a message body with the Response. The semantics of this WritableByteChannel are determined by the HTTP version of the client, and whether or not the content length has been set, through the setContentLength method. If the length of the output is not known then the output is chunked for HTTP/1.1 clients and closed for HTTP/1.0 clients.
        Specified by:
        getByteChannel in interface Response
        Returns:
        a writable byte channel used to write the message body
        Throws:
        java.io.IOException
      • getByteChannel

        public java.nio.channels.WritableByteChannel getByteChannel​(int size)
                                                             throws java.io.IOException
        Used to write a message body with the Response. The semantics of this WritableByteChannel are determined by the HTTP version of the client, and whether or not the content length has been set, through the setContentLength method. If the length of the output is not known then the output is chunked for HTTP/1.1 clients and closed for HTTP/1.0 clients.

        This will ensure that there is buffering done so that the output can be reset using the reset method. This will enable the specified number of bytes to be written without committing the response. This specified size is the minimum size that the response buffer must be.

        Specified by:
        getByteChannel in interface Response
        Parameters:
        size - the minimum size that the response buffer must be
        Returns:
        a writable byte channel used to write the message body
        Throws:
        java.io.IOException
      • isKeepAlive

        public boolean isKeepAlive()
        This is used to determine if the HTTP response message is a keep alive message or if the underlying socket was closed. Even if the client requests a connection keep alive and supports persistent connections, the response can still be closed by the server. This can be explicitly indicated by the presence of the Connection HTTP header, it can also be implicitly indicated by using version HTTP/1.0.
        Specified by:
        isKeepAlive in interface Response
        Returns:
        this returns true if the connection was closed
      • isCommitted

        public boolean isCommitted()
        This can be used to determine whether the Response has been committed. This is true if the Response was committed, either due to an explicit invocation of the commit method or due to the writing of content. If the Response has committed the reset method will not work in resetting content already written.
        Specified by:
        isCommitted in interface Response
        Returns:
        true if the response has been fully committed
      • commit

        public void commit()
                    throws java.io.IOException
        This is used to write the headers that where given to the Response. Any further attempts to give headers to the Response will be futile as only the headers that were given at the time of the first commit will be used in the message header.

        This also performs some final checks on the headers submitted. This is done to determine the optimal performance of the output. If no specific Connection header has been specified this will set the connection so that HTTP/1.0 closes by default.

        Specified by:
        commit in interface Response
        Throws:
        java.io.IOException - thrown if there was a problem writing
      • reset

        public void reset()
                   throws java.io.IOException
        This can be used to determine whether the Response has been committed. This is true if the Response was committed, either due to an explicit invocation of the commit method or due to the writing of content. If the Response has committed the reset method will not work in resetting content already written.
        Specified by:
        reset in interface Response
        Throws:
        java.io.IOException - thrown if there is a problem resetting
      • close

        public void close()
                   throws java.io.IOException
        This is used to close the connection and commit the request. This provides the same semantics as closing the output stream and ensures that the HTTP response is committed. This will throw an exception if the response can not be committed.
        Specified by:
        close in interface Response
        Throws:
        java.io.IOException - thrown if there is a problem writing