Class MultiPart.AbstractContentSource

java.lang.Object
org.eclipse.jetty.http.MultiPart.AbstractContentSource
All Implemented Interfaces:
Closeable, AutoCloseable, Content.Source
Direct Known Subclasses:
MultiPartByteRanges.ContentSource, MultiPartFormData.ContentSource
Enclosing class:
MultiPart
public abstract static class MultiPart.AbstractContentSource extends Object implements Content.Source, Closeable

An asynchronous Content.Source where MultiPart.Parts can be added to it to form a multipart content.

When this Content.Source is read, it will produce the bytes (including boundary separators) in the multipart format.

Subclasses should override customizePartHeaders(Part) to produce the right part headers depending on the specific multipart subtype (for example, multipart/form-data or multipart/byteranges, etc.).

Typical asynchronous usage is the following:

// Create a ContentSource subclass.
ContentSource source = ...;

// Add parts to the ContentSource.
source.addPart(new ByteBufferPart());
source.addPart(new PathPart());

// Close the ContentSource to signal
// that no more parts will be added.
source.close();

// The Sink where this ContentSource is written to.
Content.Sink sink = ...;

// Copy this ContentSource to the Sink.
Content.copy(source, sink, Callback.from(...));

Reading from ContentSource may be performed at any time, even if not all the parts have been added yet.

Adding parts and calling close() may be done asynchronously from other threads.

Eventually, reading from ContentSource will produce a last chunk when all the parts have been added and this ContentSource has been closed.

  • Constructor Details

    • AbstractContentSource

      public AbstractContentSource(String boundary)

  • Method Details

    • getBoundary

      public String getBoundary()
      Returns:
      the boundary string

    • getPartHeadersMaxLength

      public int getPartHeadersMaxLength()
      Returns:
      the max length of a MultiPart.Part headers, in bytes, or -1 for unlimited length

    • setPartHeadersMaxLength

      public void setPartHeadersMaxLength(int partHeadersMaxLength)
      Parameters:
      partHeadersMaxLength - the max length of a MultiPart.Part headers, in bytes, or -1 for unlimited length

    • addPart

      public boolean addPart(MultiPart.Part part)

      Adds, if possible, the given MultiPart.Part to this ContentSource.

      Parts may be added until this ContentSource is closed.

      This method returns true if the part was added, false if the part cannot be added because this ContentSource is already closed, or because it has been failed.

      Parameters:
      part - the MultiPart.Part to add
      Returns:
      whether the part has been added
      See Also:

    • close

      public void close()

      Closes this ContentSource so that no more parts may be added.

      Once this method is called, reading from this ContentSource will eventually produce a terminal multipart/form-data boundary, when all the part bytes have been read.

      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable

    • getLength

      public long getLength()
      Specified by:
      getLength in interface Content.Source
      Returns:
      the content length, if known, or -1 if the content length is unknown

    • read

      public Content.Chunk read()
      Description copied from interface: Content.Source

      Reads a chunk of content.

      See how to use this method idiomatically.

      The returned chunk could be:

      • null, to signal that there isn't a chunk of content available
      • an Content.Chunk instance with non null Content.Chunk.getFailure(), to signal that there was a failure trying to produce a chunk of content, or that the content production has been failed externally
      • a Content.Chunk instance, containing the chunk of content.

      Once a read returns an Content.Chunk instance with non-null Content.Chunk.getFailure() then if the failure is last further reads will continue to return the same failure chunk instance, otherwise further read() operations may return different non-failure chunks.

      Once a read returns a last chunk, further reads will continue to return a last chunk (although the instance may be different).

      The content reader code must ultimately arrange for a call to Retainable.release() on the returned Content.Chunk.

      Additionally, prior to the ultimate call to Retainable.release(), the reader code may make additional calls to Retainable.retain(), that must ultimately be matched by a correspondent number of calls to Retainable.release().

      Concurrent reads from different threads are not recommended, as they are inherently in a race condition.

      Reads performed outside the invocation context of a demand callback are allowed. However, reads performed with a pending demand are inherently in a race condition (the thread that reads with the thread that invokes the demand callback).

      Specified by:
      read in interface Content.Source
      Returns:
      a chunk of content, possibly a failure instance, or null
      See Also:

    • customizePartHeaders

      protected HttpFields customizePartHeaders(MultiPart.Part part)

    • demand

      public void demand(Runnable demandCallback)
      Description copied from interface: Content.Source

      Demands to invoke the given demand callback parameter when a chunk of content is available.

      See how to use this method idiomatically.

      Implementations guarantee that calls to this method are safely reentrant so that stack overflows are avoided in the case of mutual recursion between the execution of the Runnable callback and a call to this method. Invocations of the passed Runnable are serialized and a callback for demand call is not invoked until any previous demand callback has returned. Thus the Runnable should not block waiting for a callback of a future demand call.

      The demand callback may be invoked spuriously: a subsequent call to Content.Source.read() may return null.

      Calling this method establishes a pending demand, which is fulfilled when the demand callback is invoked.

      Calling this method when there is already a pending demand results in an IllegalStateException to be thrown.

      If the invocation of the demand callback throws an exception, then Content.Source.fail(Throwable) is called.

      Specified by:
      demand in interface Content.Source
      Parameters:
      demandCallback - the demand callback to invoke where there is a content chunk available
      See Also:

    • fail

      public void fail(Throwable failure)
      Description copied from interface: Content.Source

      Fails this content source with a last failure chunk, failing and discarding accumulated content chunks that were not yet read.

      The failure may be notified to the content reader at a later time, when the content reader reads a content chunk, via a Content.Chunk instance with a non null Content.Chunk.getFailure().

      If Content.Source.read() has returned a last chunk, this is a no operation.

      Typical failure: the content being aborted by user code, or idle timeouts.

      If this method has already been called, then it is a no operation.

      Specified by:
      fail in interface Content.Source
      Parameters:
      failure - the cause of the failure
      See Also: