org.apache.camel

Interface StreamCache

All Known Implementing Classes:

ByteArrayInputStreamCache, FileInputStreamCache, InputStreamCache, ReaderCache, SourceCache, StreamSourceCache

public interface StreamCache

Tagging interface to indicate that a type is capable of caching the underlying data stream.

This is a useful feature for avoiding message re-readability issues. This interface is mainly used by the StreamCachingStrategy for determining if/how to wrap a stream-based message.

The Camel routing engine uses the CamelInternalProcessor.StreamCachingAdvice to apply the stream cache during routing.

It is recommended in the copy() method to let the copied stream start from the start. If the implementation does not support copy, then return null.

Version:

Field Summary

Fields

Modifier and Type	Field and Description
static long	DEFAULT_SPOOL_THRESHOLD

Method Summary

Methods

Modifier and Type	Method and Description
StreamCache	copy() Create a copy of the stream.
boolean	inMemory() Whether this StreamCache is in memory only or spooled to persistent storage such as files.
long	length() Gets the length of the cached stream.
void	reset() Resets the StreamCache for a new stream consumption.
void	writeTo(OutputStream os) Writes the stream to the given output

Field Detail

DEFAULT_SPOOL_THRESHOLD

static final long DEFAULT_SPOOL_THRESHOLD

See Also:

Constant Field Values

Method Detail

reset

void reset()

Resets the StreamCache for a new stream consumption.

writeTo

void writeTo(OutputStream os)
             throws IOException

Writes the stream to the given output

Parameters:

os - the destination to write to

Throws:

IOException - is thrown if write fails

copy

StreamCache copy()
                 throws IOException

Create a copy of the stream. If possible use the same cached data in the copied instance.

This method is useful for parallel processing.

Implementations note: A copy of the stream is recommended to read from the start of the stream.

Returns:

a copy, or null if copy is not possible

Throws:

IOException - is thrown if the copy fails

inMemory

boolean inMemory()

Whether this StreamCache is in memory only or spooled to persistent storage such as files.

length

long length()

Gets the length of the cached stream.

The implementation may return 0 in cases where the length cannot be computed, or if the implementation does not support this.

Returns:

number of bytes in the cache.