bayou.bytes

Class PushbackByteSource

java.lang.Object

bayou.bytes.PushbackByteSource

All Implemented Interfaces:

ByteSource

public class PushbackByteSource
extends Object
implements ByteSource

A ByteSource wrapper that supports unread().

`unread(bb)` stores `bb` internally to be served in the next `read()`. read() will remove the stored `bb`. skip() may also remove the stored `bb`.

At most one ByteBuffer can be stored at a time. Consecutive unread() calls are not supported.

Constructor Summary

Constructors

Constructor and Description
PushbackByteSource(ByteSource origin) Create a PushbackByteSource wrapper of the `origin` ByteSource.

Method Summary

Instance Methods
void	unread(ByteBuffer bb) Unread `bb`.
Async<ByteBuffer>	read() Read the next chunk of bytes.
long	skip(long n) Try to skip forward `n` bytes.
Async<Void>	close() Close this source.

Methods inherited from class java.lang.Object

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

Methods inherited from interface bayou.bytes.ByteSource

asString, asString, readAll, toSink

Constructor Detail

PushbackByteSource

public PushbackByteSource(ByteSource origin)

Create a PushbackByteSource wrapper of the `origin` ByteSource.

Method Detail

unread

public void unread(ByteBuffer bb)
            throws IllegalStateException

Unread `bb`.

`bb` is stored, to be served in then next read().

If there is already a ByteBuffer stored from a previous unread(), this method throws IllegalStateException.

Throws:

IllegalStateException - if there is already a ByteBuffer stored from a previous unread(); or if this source has been closed.

read

public Async<ByteBuffer> read()
                       throws IllegalStateException

Read the next chunk of bytes.

If there is a `bb` stored from a previous unread(), it's removed, and this read() action succeeds immediately with that `bb`. Otherwise, this call is equivalent to `origin.read()`.

Specified by:

read in interface ByteSource

Throws:

IllegalStateException - if this source is closed.

skip

public long skip(long n)
          throws IllegalArgumentException,
                 IllegalStateException

Try to skip forward `n` bytes.

If there is a `bb` stored from a previous unread(), its position may be adjusted, or it may be removed entirely.

Specified by:

skip in interface ByteSource

Parameters:

n - number of bytes to skip; n >= 0.

Returns:

number of bytes (m) actually skipped. 0 <= m <= n.

Throws:

IllegalStateException - if this source is closed.

IllegalArgumentException - if n < 0.

close

public Async<Void> close()

Close this source.

Specified by:

close in interface ByteSource