Package org.eclipse.jetty.proxy

Class AfterContentTransformer

java.lang.Object

org.eclipse.jetty.proxy.AfterContentTransformer

All Implemented Interfaces:

AsyncMiddleManServlet.ContentTransformer, Destroyable

public abstract class AfterContentTransformer
extends Object
implements AsyncMiddleManServlet.ContentTransformer, Destroyable

A specialized transformer for AsyncMiddleManServlet that performs the transformation when the whole content has been received.

The content is buffered in memory up to a configurable maximum size, after which it is overflown to a file on disk. The overflow file is saved in the overflow directory as a temporary file with a name starting with the input prefix and default suffix.

Application must implement the transformation method to transform the content.

The transformed content is buffered in memory up to a configurable maximum size after which it is overflown to a file on disk. The overflow file is saved in the overflow directory as a temporary file with a name starting with the getOutputFilePrefix() output prefix} and default suffix.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	AfterContentTransformer.Sink	The target to where the transformed content is written after the transformation.
class	AfterContentTransformer.Source	The source from where the original content is read to be transformed.

Field Summary

Fields inherited from interface org.eclipse.jetty.proxy.AsyncMiddleManServlet.ContentTransformer

IDENTITY

Constructor Summary

Constructors

Constructor	Description
AfterContentTransformer()

Method Summary

Modifier and Type	Method	Description
void	destroy()
String	getInputFilePrefix()
long	getMaxInputBufferSize()	Returns the maximum input buffer size, after which the input is overflown to disk.
long	getMaxOutputBufferSize()	Returns the maximum output buffer size, after which the output is overflown to disk.
String	getOutputFilePrefix()
Path	getOverflowDirectory()	Returns the directory where input and output are overflown to temporary files if they exceed, respectively, the max input size or the max output size.
void	setInputFilePrefix(String inputFilePrefix)
void	setMaxInputBufferSize(long maxInputBufferSize)
void	setMaxOutputBufferSize(long maxOutputBufferSize)
void	setOutputFilePrefix(String outputFilePrefix)
void	setOverflowDirectory(Path overflowDirectory)
final void	transform(ByteBuffer input, boolean finished, List<ByteBuffer> output)	Transforms the given input byte buffers into (possibly multiple) byte buffers.
abstract boolean	transform(AfterContentTransformer.Source source, AfterContentTransformer.Sink sink)	Transforms the original content read from the source into transformed content written to the sink.

Methods inherited from class java.lang.Object

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

Constructor Details

AfterContentTransformer

public AfterContentTransformer()

Method Details

getOverflowDirectory

public Path getOverflowDirectory()

Returns the directory where input and output are overflown to temporary files if they exceed, respectively, the max input size or the max output size.

Defaults to the directory pointed by the java.io.tmpdir system property.

Returns:

the overflow directory path

See Also:

• setOverflowDirectory(Path)

setOverflowDirectory

public void setOverflowDirectory(Path overflowDirectory)

Parameters:

overflowDirectory - the overflow directory path

See Also:

• getOverflowDirectory()

getInputFilePrefix

public String getInputFilePrefix()

Returns:

the prefix of the input overflow temporary files

See Also:

• setInputFilePrefix(String)

setInputFilePrefix

public void setInputFilePrefix(String inputFilePrefix)

Parameters:

inputFilePrefix - the prefix of the input overflow temporary files

See Also:

• getInputFilePrefix()

getMaxInputBufferSize

public long getMaxInputBufferSize()

Returns the maximum input buffer size, after which the input is overflown to disk.

Defaults to 1 MiB, i.e. 1048576 bytes.

Returns:

the max input buffer size

See Also:

• setMaxInputBufferSize(long)

setMaxInputBufferSize

public void setMaxInputBufferSize(long maxInputBufferSize)

Parameters:

maxInputBufferSize - the max input buffer size

See Also:

• getMaxInputBufferSize()

getOutputFilePrefix

public String getOutputFilePrefix()

Returns:

the prefix of the output overflow temporary files

See Also:

• setOutputFilePrefix(String)

setOutputFilePrefix

public void setOutputFilePrefix(String outputFilePrefix)

Parameters:

outputFilePrefix - the prefix of the output overflow temporary files

See Also:

• getOutputFilePrefix()

getMaxOutputBufferSize

public long getMaxOutputBufferSize()

Returns the maximum output buffer size, after which the output is overflown to disk.

Defaults to 1 MiB, i.e. 1048576 bytes.

Returns:

the max output buffer size

See Also:

• setMaxOutputBufferSize(long)

setMaxOutputBufferSize

public void setMaxOutputBufferSize(long maxOutputBufferSize)

Parameters:

maxOutputBufferSize - the max output buffer size

transform

public final void transform(ByteBuffer input,
 boolean finished,
 List<ByteBuffer> output)
                     throws IOException

Description copied from interface: AsyncMiddleManServlet.ContentTransformer

Transforms the given input byte buffers into (possibly multiple) byte buffers.

The transformation must happen synchronously in the context of a call to this method (it is not supported to perform the transformation in another thread spawned during the call to this method). The transformation may happen or not, depending on the transformer implementation. For example, a buffering transformer may buffer the input aside, and only perform the transformation when the whole input is provided (by looking at the finished flag).

The input buffer will be cleared and reused after the call to this method. Implementations that want to buffer aside the input (or part of it) must copy the input bytes that they want to buffer.

Typical implementations:

 // Identity transformation (no transformation, the input is copied to the output)
 public void transform(ByteBuffer input, boolean finished, List<ByteBuffer> output)
 {
     output.add(input);
 }

 // Discard transformation (all input is discarded)
 public void transform(ByteBuffer input, boolean finished, List<ByteBuffer> output)
 {
     // Empty
 }

 // Buffering identity transformation (all input is buffered aside until it is finished)
 public void transform(ByteBuffer input, boolean finished, List<ByteBuffer> output)
 {
     ByteBuffer copy = ByteBuffer.allocate(input.remaining());
     copy.put(input).flip();
     store(copy);

     if (finished)
     {
         List<ByteBuffer> copies = retrieve();
         output.addAll(copies);
     }
 }
 

Specified by:

transform in interface AsyncMiddleManServlet.ContentTransformer

Parameters:

input - the input content to transform (may be of length zero)

finished - whether the input content is finished or more will come

output - where to put the transformed output content

Throws:

IOException - in case of transformation failures

transform

public abstract boolean transform(AfterContentTransformer.Source source,
 AfterContentTransformer.Sink sink)
                           throws IOException

Transforms the original content read from the source into transformed content written to the sink.

The transformation must happen synchronously in the context of a call to this method (it is not supported to perform the transformation in another thread spawned during the call to this method).

Differently from transform(ByteBuffer, boolean, List), this method is invoked only when the whole content is available, and offers a blocking API via the InputStream and OutputStream that can be obtained from AfterContentTransformer.Source and AfterContentTransformer.Sink respectively.

Implementations may read the source, inspect the input bytes and decide that no transformation is necessary, and therefore the source must be copied unchanged to the sink. In such case, the implementation must return false to indicate that it wishes to just pipe the bytes from the source to the sink.

Typical implementations:

 // Identity transformation (no transformation, the input is copied to the output)
 public boolean transform(Source source, Sink sink)
 {
     org.eclipse.jetty.util.IO.copy(source.getInputStream(), sink.getOutputStream());
     return true;
 }
 

Parameters:

source - where the original content is read

sink - where the transformed content is written

Returns:

true if the transformation happened and the transformed bytes have been written to the sink, false if no transformation happened and the source must be copied to the sink.

Throws:

IOException - if the transformation fails

destroy

public void destroy()

Specified by:

destroy in interface Destroyable