Class ResponseWrapper

java.lang.Object
org.simpleframework.http.ResponseWrapper
All Implemented Interfaces:
Response, ResponseHeader, StatusLine
public class ResponseWrapper extends Object implements Response
The ResponseWrapper object is used so that the original Response object can be wrapped in a filtering proxy object. This allows a container to interact with an implementation of this with overridden methods providing specific functionality. the Response object in a concurrent environment. 

   public void handle(Request req, Response resp) {
      handler.handle(req, new ZipResponse(resp));
   }
The above is an example of how the ResponseWrapper can be used to provide extra functionality to a Response in a transparent manner. Such an implementation could apply a Content-Encoding header and compress the response for performance over a slow network. Filtering can be applied with the use of layered Container objects.
Author:
Niall Gallagher
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected Response
    response
    This is the response instance that is being wrapped.

  • Constructor Summary

    Constructors
    Constructor
    Description
    ResponseWrapper(Response response)
    Constructor for ResponseWrapper object.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    add(String name, int value)
    This can be used to add a HTTP message header to this object.
    void
    add(String name, String value)
    This can be used to add a HTTP message header to this object.
    void
    addDate(String name, long date)
    This is used as a convenience method for adding a header that needs to be parsed into a HTTPdate string.
    void
    close()
    This is used to close the connection and commit the request.
    void
    commit()
    This is used to write the headers that where given to the Response.
    boolean
    contains(String name)
    This is used to see if there is a HTTP message header with the given name in this container.
    WritableByteChannel
    getByteChannel()
    Used to write a message body with the Response.
    WritableByteChannel
    getByteChannel(int size)
    Used to write a message body with the Response.
    int
    getCode()
    This represents the status code of the HTTP response.
    int
    getContentLength()
    This is a convenience method that can be used to determine the length of the message body.
    ContentType
    getContentType()
    This is a convenience method that can be used to determine the content type of the message body.
    Cookie
    getCookie(String name)
    This returns the Cookie object stored under the specified name.
    List<Cookie>
    getCookies()
    This returns all Cookie objects stored under the specified name.
    long
    getDate(String name)
    This can be used to get the value of the first message header that has the specified name.
    int
    getInteger(String name)
    This can be used to get the value of the first message header that has the specified name.
    int
    getMajor()
    This can be used to get the major number from a HTTP version.
    int
    getMinor()
    This can be used to get the minor number from a HTTP version.
    List<String>
    getNames()
    This is used to acquire the names of the of the headers that have been set in the response.
    OutputStream
    getOutputStream()
    Used to write a message body with the Response.
    OutputStream
    getOutputStream(int size)
    Used to write a message body with the Response.
    PrintStream
    getPrintStream()
    This method is provided for convenience so that the HTTP content can be written using the print methods provided by the PrintStream.
    PrintStream
    getPrintStream(int size)
    This method is provided for convenience so that the HTTP content can be written using the print methods provided by the PrintStream.
    String
    getText()
    This can be used to retrieve the text of a HTTP status line.
    String
    getTransferEncoding()
    This is a convenience method that can be used to determine the content type of the message body.
    String
    getValue(String name)
    This can be used to get the value of the first message header that has the specified name.
    List<String>
    getValues(String name)
    This can be used to get the values of HTTP message headers that have the specified name.
    boolean
    isCommitted()
    This can be used to determine whether the Response has been committed.
    void
    remove(String name)
    This is used to remove the named header from the response.
    void
    reset()
    This can be used to determine whether the Response has been committed.
    void
    set(String name, int value)
    This can be used to set a HTTP message header to this object.
    void
    set(String name, String value)
    This can be used to set a HTTP message header to this object.
    void
    setCode(int code)
    This method allows the status for the response to be changed.
    void
    setContentLength(int length)
    This should be used when the size of the message body is known.
    Cookie
    setCookie(String name, String value)
    The setCookie method is used to set a cookie value with the cookie name.
    Cookie
    setCookie(Cookie cookie)
    The setCookie method is used to set a cookie value with the cookie name.
    void
    setDate(String name, long date)
    This is used as a convenience method for adding a header that needs to be parsed into a HTTP date string.
    void
    setMajor(int major)
    This can be used to set the major number from a HTTP version.
    void
    setMinor(int minor)
    This can be used to get the minor number from a HTTP version.
    void
    setText(String text)
    This is used to set the text of the HTTP status line.

    Methods inherited from class Object

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

  • Field Details

    • response

      protected Response response
      This is the response instance that is being wrapped.

  • Constructor Details

    • ResponseWrapper

      public ResponseWrapper(Response response)
      Constructor for ResponseWrapper object. This allows the original Response object to be wrapped so that adjustments to the behavior of a request object handed to the container can be provided by a subclass implementation.
      Parameters:
      response - the response object that is being wrapped

  • Method Details

    • getCode

      public int getCode()
      This represents the status code of the HTTP response. The response code represents the type of message that is being sent to the client. For a description of the codes see RFC 2616 section 10, Status Code Definitions.
      Specified by:
      getCode in interface StatusLine
      Returns:
      the status code that this HTTP response has

    • setCode

      public void setCode(int code)
      This method allows the status for the response to be changed. This MUST be reflected the the response content given to the client. For a description of the codes see RFC 2616 section 10, Status Code Definitions.
      Specified by:
      setCode in interface StatusLine
      Parameters:
      code - the new status code for the HTTP response

    • getText

      public String getText()
      This can be used to retrieve the text of a HTTP status line. This is the text description for the status code. This should match the status code specified by the RFC.
      Specified by:
      getText in interface StatusLine
      Returns:
      the message description of the response

    • setText

      public void setText(String text)
      This is used to set the text of the HTTP status line. This should match the status code specified by the RFC.
      Specified by:
      setText in interface StatusLine
      Parameters:
      text - the descriptive text message of the status

    • getMajor

      public int getMajor()
      This can be used to get the major number from a HTTP version. The major version corresponds to the major type that is the 1 of a HTTP/1.0 version string.
      Specified by:
      getMajor in interface StatusLine
      Returns:
      the major version number for the request message

    • setMajor

      public void setMajor(int major)
      This can be used to set the major number from a HTTP version. The major version corresponds to the major type that is the 1 of a HTTP/1.0 version string.
      Specified by:
      setMajor in interface StatusLine
      Parameters:
      major - the major version number for the request message

    • getMinor

      public int getMinor()
      This can be used to get the minor number from a HTTP version. The minor version corresponds to the major type that is the 0 of a HTTP/1.0 version string. This is used to determine if the request message has keep alive semantics.
      Specified by:
      getMinor in interface StatusLine
      Returns:
      the minor version number for the request message

    • setMinor

      public void setMinor(int minor)
      This can be used to get the minor number from a HTTP version. The minor version corresponds to the major type that is the 0 of a HTTP/1.0 version string. This is used to determine if the request message has keep alive semantics.
      Specified by:
      setMinor in interface StatusLine
      Parameters:
      minor - the minor version number for the request message

    • getNames

      public List<String> getNames()
      This is used to acquire the names of the of the headers that have been set in the response. This can be used to acquire all header values by name that have been set within the response. If no headers have been set this will return an empty list.
      Specified by:
      getNames in interface ResponseHeader
      Returns:
      a list of strings representing the set header names

    • add

      public void add(String name, String value)
      This can be used to add a HTTP message header to this object. The name and value of the HTTP message header will be used to create a HTTP message header object which can be retrieved using the getValue in combination with the get methods.
      Specified by:
      add in interface ResponseHeader
      Parameters:
      name - the name of the HTTP message header to be added
      value - the value the HTTP message header will have

    • add

      public void add(String name, int value)
      This can be used to add a HTTP message header to this object. The name and value of the HTTP message header will be used to create a HTTP message header object which can be retrieved using the getInteger in combination with the get methods.
      Specified by:
      add in interface ResponseHeader
      Parameters:
      name - the name of the HTTP message header to be added
      value - the value the HTTP message header will have

    • addDate

      public void addDate(String name, long date)
      This is used as a convenience method for adding a header that needs to be parsed into a HTTPdate string. This will convert the date given into a date string defined in RFC 2616 sec 3.3.1.
      Specified by:
      addDate in interface ResponseHeader
      Parameters:
      name - the name of the HTTP message header to be added
      date - the value constructed as an RFC 1123 date string

    • set

      public void set(String name, String value)
      This can be used to set a HTTP message header to this object. The name and value of the HTTP message header will be used to create a HTTP message header object which can be retrieved using the getValue in combination with the get methods. This will perform a remove using the issued header name before the header value is set.
      Specified by:
      set in interface ResponseHeader
      Parameters:
      name - the name of the HTTP message header to be added
      value - the value the HTTP message header will have

    • set

      public void set(String name, int value)
      This can be used to set a HTTP message header to this object. The name and value of the HTTP message header will be used to create a HTTP message header object which can be retrieved using the getValue in combination with the get methods. This will perform a remove using the issued header name before the header value is set.
      Specified by:
      set in interface ResponseHeader
      Parameters:
      name - the name of the HTTP message header to be added
      value - the value the HTTP message header will have

    • setDate

      public void setDate(String name, long date)
      This is used as a convenience method for adding a header that needs to be parsed into a HTTP date string. This will convert the date given into a date string defined in RFC 2616 sec 3.3.1. This will perform a remove using the issued header name before the header value is set.
      Specified by:
      setDate in interface ResponseHeader
      Parameters:
      name - the name of the HTTP message header to be added
      date - the value constructed as an RFC 1123 date string

    • remove

      public void remove(String name)
      This is used to remove the named header from the response. This removes all header values assigned to the specified name. If it does not exist then this will return without modifying the HTTP response. Headers names removed are case insensitive.
      Specified by:
      remove in interface ResponseHeader
      Parameters:
      name - the HTTP message header to remove from the response

    • contains

      public boolean contains(String name)
      This is used to see if there is a HTTP message header with the given name in this container. If there is a HTTP message header with the specified name then this returns true otherwise false.
      Specified by:
      contains in interface ResponseHeader
      Parameters:
      name - the HTTP message header to get the value from
      Returns:
      this returns true if the HTTP message header exists

    • getValue

      public String getValue(String name)
      This can be used to get the value of the first message header that has the specified name. This will return the full string representing the named header value. If the named header does not exist then this will return a null value.
      Specified by:
      getValue in interface ResponseHeader
      Parameters:
      name - the HTTP message header to get the value from
      Returns:
      this returns the value that the HTTP message header

    • getInteger

      public int getInteger(String name)
      This can be used to get the value of the first message header that has the specified name. This will return the integer representing the named header value. If the named header does not exist then this will return a value of minus one, -1.
      Specified by:
      getInteger in interface ResponseHeader
      Parameters:
      name - the HTTP message header to get the value from
      Returns:
      this returns the value that the HTTP message header

    • getDate

      public long getDate(String name)
      This can be used to get the value of the first message header that has the specified name. This will return the long value representing the named header value. If the named header does not exist then this will return a value of minus one, -1.
      Specified by:
      getDate in interface ResponseHeader
      Parameters:
      name - the HTTP message header to get the value from
      Returns:
      this returns the value that the HTTP message header

    • getValues

      public List<String> getValues(String name)
      This can be used to get the values of HTTP message headers that have the specified name. This is a convenience method that will present that values as tokens extracted from the header. This has obvious performance benefits as it avoids having to deal with substring and trim calls.

      The tokens returned by this method are ordered according to there HTTP quality values, or "q" values, see RFC 2616 section 3.9. This also strips out the quality parameter from tokens returned. So "image/html; q=0.9" results in "image/html". If there are no "q" values present then order is by appearance.

      The result from this is either the trimmed header value, that is, the header value with no leading or trailing whitespace or an array of trimmed tokens ordered with the most preferred in the lower indexes, so index 0 is has highest preference.

      Specified by:
      getValues in interface ResponseHeader
      Parameters:
      name - the name of the headers that are to be retrieved
      Returns:
      ordered list of tokens extracted from the header(s)

    • setCookie

      public Cookie setCookie(Cookie cookie)
      The setCookie method is used to set a cookie value with the cookie name. This will add a cookie to the response stored under the name of the cookie, when this is committed it will be added as a Set-Cookie header to the resulting response.
      Specified by:
      setCookie in interface ResponseHeader
      Parameters:
      cookie - this is the cookie to be added to the response
      Returns:
      returns the cookie that has been set in the response

    • setCookie

      public Cookie setCookie(String name, String value)
      The setCookie method is used to set a cookie value with the cookie name. This will add a cookie to the response stored under the name of the cookie, when this is committed it will be added as a Set-Cookie header to the resulting response. This is a convenience method that avoids cookie creation.
      Specified by:
      setCookie in interface ResponseHeader
      Parameters:
      name - this is the cookie to be added to the response
      value - this is the cookie value that is to be used
      Returns:
      returns the cookie that has been set in the response

    • getCookie

      public Cookie getCookie(String name)
      This returns the Cookie object stored under the specified name. This is used to retrieve cookies that have been set with the setCookie methods. If the cookie does not exist under the specified name this will return null.
      Specified by:
      getCookie in interface ResponseHeader
      Parameters:
      name - this is the name of the cookie to be retrieved
      Returns:
      returns the cookie object send with the request

    • getCookies

      public List<Cookie> getCookies()
      This returns all Cookie objects stored under the specified name. This is used to retrieve cookies that have been set with the setCookie methods. If there are no cookies then this will return an empty list.
      Specified by:
      getCookies in interface ResponseHeader
      Returns:
      returns all the cookie objects for this response

    • getContentType

      public ContentType getContentType()
      This is a convenience method that can be used to determine the content type of the message body. This will determine whether there is a Content-Type header, if there is then this will parse that header and represent it as a typed object which will expose the various parts of the HTTP header.
      Specified by:
      getContentType in interface ResponseHeader
      Returns:
      this returns the content type value if it exists

    • getTransferEncoding

      public String getTransferEncoding()
      This is a convenience method that can be used to determine the content type of the message body. This will determine whether there is a Transfer-Encoding header, if there is then this will parse that header and return the first token in the comma separated list of values, which is the primary value.
      Specified by:
      getTransferEncoding in interface ResponseHeader
      Returns:
      this returns the transfer encoding value if it exists

    • getContentLength

      public int getContentLength()
      This is a convenience method that can be used to determine the length of the message body. This will determine if there is a Content-Length header, if it does then the length can be determined, if not then this returns -1.
      Specified by:
      getContentLength in interface ResponseHeader
      Returns:
      content length, or -1 if it cannot be determined

    • setContentLength

      public void setContentLength(int 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

    • getOutputStream

      public OutputStream getOutputStream() throws 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. The OutputStream issued must be thread safe so that it can be used in a concurrent environment.
      Specified by:
      getOutputStream in interface Response
      Returns:
      an output stream used to write the response body
      Throws:
      IOException - this is thrown if there was an I/O error

    • getOutputStream

      public OutputStream getOutputStream(int size) throws 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. The OutputStream issued must be thread safe so that it can be used in a concurrent environment.

      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 used to write the response body
      Throws:
      IOException - this is thrown if there was an I/O error

    • getPrintStream

      public PrintStream getPrintStream() throws 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.

      Implementations of the Response must guarantee that this can be invoked repeatedly without effecting any issued OutputStream or PrintStream object.

      Specified by:
      getPrintStream in interface Response
      Returns:
      a print stream used for writing the response body
      Throws:
      IOException - this is thrown if there was an I/O error

    • getPrintStream

      public PrintStream getPrintStream(int size) throws 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.

      Implementations of the Response must guarantee that this can be invoked repeatedly without effecting any issued OutputStream or PrintStream object.

      Specified by:
      getPrintStream in interface Response
      Parameters:
      size - the minimum size that the response buffer must be
      Returns:
      a print stream used for writing the response body
      Throws:
      IOException - this is thrown if there was an I/O error

    • getByteChannel

      public WritableByteChannel getByteChannel() throws 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:
      IOException

    • getByteChannel

      public WritableByteChannel getByteChannel(int size) throws 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:
      IOException

    • 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 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:
      IOException - thrown if there was a problem writing

    • reset

      public void reset() throws 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:
      IOException - thrown if there is a problem resetting

    • close

      public void close() throws 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:
      IOException - thrown if there is a problem writing