Package wt.util

Class MPInputStream

java.lang.Object
java.io.InputStream
java.io.FilterInputStream
wt.util.MPInputStream
All Implemented Interfaces:
Closeable, AutoCloseable, wt.util.MPInputStreamIfc
public class MPInputStream extends FilterInputStream implements wt.util.MPInputStreamIfc
A MP input stream is a filter that allows a business class to read consecutive multipart data object bodies whilst alleviating the associated pain. It does this by parsing out object body headers and values, and reading the input stream for the business class whilst checking for the encapsulation boundaries. Analagous to other input streams, MP will respond to read requests as long as there is data in the present object body. Once the end of the data for said object body is reached, a negative one is returned on the next read.

The only required steps are to instantiate a new MPInputStream (passing in the HTTPRequest's input stream and CGI_MULTIPART_BOUNDARY), and to call MP's hasMoreObjectBodies method. Provided the the instantiation succeeds and the return value of the hasMoreObjectBodies method call is true, the business class is free to proceed with reading of the first object body.

Upon receipt of a negative one from a read request, said object body is finished. The return value of another call to hasMoreObjectBodies will indicate if another object body is available for reading.

Note that this input stream filter reads the object body data as bytes, and thus does not impinge any format nor conversion upon the data therein. Thus if the object body data is, for example, base64 encoded, the resultant reads of the business class will get base64 encoded data. It is in this way, that this filter can operate independant of the data enclosed in the object body. It is therefore incumbant on the business class to perform any post processing of the data that may be necessary.

Supported API: true
Extendable: false

  • Constructor Details

    • MPInputStream

      public MPInputStream(InputStream in, String boundary)
      Creates a new MPInputStream initialized with the specified input stream and object body boundary

      Supported API: true
      Parameters:
      in - the input stream
      boundary - the encapsulation boundary string

  • Method Details

    • setEncoding

      public void setEncoding(String encoding)
      Set character encoding to be returned by getEncoding method. Useful if the creator of a MPInputStream want to communicate a known character encoding to a body part processing method.

      Supported API: true
      Specified by:
      setEncoding in interface wt.util.MPInputStreamIfc
      Parameters:
      encoding - the character encoding

    • getEncoding

      public String getEncoding(String encoding)
      Deprecated.


      Supported API: true
      get the character encoding set by setEncoding method. Returns null if not encoding has been set for this MPInputStream.
      Returns:
      encoding the character encoding

    • getEncoding

      public String getEncoding()
      get the character encoding set by setEncoding method. Returns null if not encoding has been set for this MPInputStream.

      Supported API: true
      Specified by:
      getEncoding in interface wt.util.MPInputStreamIfc
      Returns:
      encoding the character encoding

    • hasMoreObjectBodies

      public boolean hasMoreObjectBodies() throws IOException
      Setup read of next object body if one is available. Accomplished by checking that the encapsulation boundary at the top of the header is what we expect, generate a hashtable of the object body headers for later retrieval, and set the stream to the top of the body data for subsequent reads.

      Supported API: true

      Specified by:
      hasMoreObjectBodies in interface wt.util.MPInputStreamIfc
      Throws:
      IOException - is thrown if error on reading object body header(s) or encapsulation boundary doesn't match that which was passed into the constructor, of read from the boundary object body header.

      Note: this method must be called and a value of true returned prior to getBodyHeaders() and/or getBodyHeader(String s) calls.

    • getBodyHeaders

      public Enumeration getBodyHeaders()
      Public accessor to Object Body Headers and values.

      Supported API: true
      Specified by:
      getBodyHeaders in interface wt.util.MPInputStreamIfc

    • getBodyHeader

      public String getBodyHeader(String s)
      Public accessor to specific Object Body Header.

      Supported API: true
      Specified by:
      getBodyHeader in interface wt.util.MPInputStreamIfc
      Parameters:
      s - string key for which to get value.

    • containsBodyHeader

      public boolean containsBodyHeader(String s)
      Public checker for specific Object Body Header.

      Supported API: true
      Specified by:
      containsBodyHeader in interface wt.util.MPInputStreamIfc
      Parameters:
      s - string key for which to get value.

    • read

      public final int read() throws IOException
      Reads a byte of data. The method will block if no input is available.

      Supported API: true
      Specified by:
      read in interface wt.util.MPInputStreamIfc
      Overrides:
      read in class FilterInputStream
      Returns:
      the byte read, or -1 if the end of the stream is reached.
      Throws:
      IOException - If an I/O error has occurred. We are overriding this to return 0 bytes for now. Should just call read (byte[], 0, 1)...maybe?

    • read

      public final int read(byte[] b) throws IOException
      Reads up to b.length bytes of data from this input stream into an array of bytes.

      The read method of MPInputStream calls the read method of three arguments with the arguments b, 0, and b.length.

      Supported API: true

      Specified by:
      read in interface wt.util.MPInputStreamIfc
      Overrides:
      read in class FilterInputStream
      Parameters:
      b - the buffer into which the data is read.
      Returns:
      the total number of bytes read into the buffer, or -1 is there is no more data because the end of the stream has been reached.
      Throws:
      IOException - if an I/O error occurs.
      Since:
      JDK1.0
      See Also:

    • read

      public final int read(byte[] b, int off, int len) throws IOException
      Reads up to len bytes of data from this MP input stream into an array of bytes. This method blocks until some input is available.

      This read method of MPInputStream reads bytes out of an internal buffer.

      Supported API: true

      Specified by:
      read in interface wt.util.MPInputStreamIfc
      Overrides:
      read in class FilterInputStream
      Parameters:
      b - the buffer into which the data is read.
      off - the start offset of the data.
      len - the maximum number of bytes read.
      Returns:
      the total number of bytes read into the buffer, or -1 if there is no more data because the end of the object body has been reached.
      Throws:
      IOException - if an I/O error occurs.

    • skip

      public long skip(long n) throws IOException
      Skips bytes of input.

      Supported API: true
      Specified by:
      skip in interface wt.util.MPInputStreamIfc
      Overrides:
      skip in class FilterInputStream
      Parameters:
      n - bytes to be skipped
      Returns:
      actual number of bytes skipped
      Throws:
      IOException - If an I/O error has occurred.

    • available

      public int available()
      Returns the number of bytes that can be read without blocking. Returns number of bytes body bytes already read into local buffer.

      Supported API: true
      Specified by:
      available in interface wt.util.MPInputStreamIfc
      Overrides:
      available in class FilterInputStream
      Returns:
      number of bytes available

    • readString

      public String readString() throws IOException
      Reads the remainder of the current body part into a string.

      Supported API: true
      Specified by:
      readString in interface wt.util.MPInputStreamIfc
      Returns:
      String read using the encoding set for this stream
      Throws:
      IOException - if an I/O error occurs.