Top Description Fields Constructors Methods
org.eclipse.jgit.util.io

public Class UnionInputStream

extends InputStream
Class Inheritance
Imports
java.io.IOException, .InputStream, java.util.ArrayDeque, .Deque
An InputStream which reads from one or more InputStreams.

This stream may enter into an EOF state, returning -1 from any of the read methods, and then later successfully read additional bytes if a new InputStream is added after reaching EOF.

Currently this stream does not support the mark/reset APIs. If mark and later reset functionality is needed the caller should wrap this stream with a java.io.BufferedInputStream.

Field Summary

Modifier and TypeField and Description
private static final InputStream
EOF

private final Deque<InputStream>
streams

Constructor Summary

AccessConstructor and Description
public
UnionInputStream()

Create an empty InputStream that is currently at EOF state.

public
UnionInputStream(InputStream...
streams to be pushed onto this stream.
inputStreams)

Create an InputStream that is a union of the individual streams.

Method Summary

Modifier and TypeMethod and Description
public void
add(InputStream
the stream to add; must not be null.
in)

Add the given InputStream onto the end of the stream queue.

public int
available()

Overrides java.io.InputStream.available.

Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking, which may be 0, or 0 when end of stream is detected.

public void
close()

Overrides java.io.InputStream.close.

Implements java.io.Closeable.close.

Closes this input stream and releases any system resources associated with the stream.

private InputStream
head()

public boolean

Returns:

true if there are no more streams to read from.
isEmpty()

Returns true if there are no more InputStreams in the stream queue.

private void
pop()

public int
read()

Implements abstract java.io.InputStream.read.

Reads the next byte of data from the input stream.

public int
read(byte[]
the buffer into which the data is read.
b, int
the start offset in array b at which the data is written.
off, int
the maximum number of bytes to read.
len)

Overrides java.io.InputStream.read.

Reads up to len bytes of data from the input stream into an array of bytes.

public long
skip(long
the number of bytes to be skipped.
count)

Overrides java.io.InputStream.skip.

Skips over and discards n bytes of data from this input stream.

Inherited from java.io.InputStream:
markmarkSupportednullInputStreamreadreadAllBytesreadNBytesreadNBytesresetskipNBytestransferTo

Field Detail

EOFback to summary
private static final InputStream EOF
streamsback to summary
private final Deque<InputStream> streams

Constructor Detail

UnionInputStreamback to summary
public UnionInputStream()

Create an empty InputStream that is currently at EOF state.

UnionInputStreamback to summary
public UnionInputStream(InputStream... inputStreams)

Create an InputStream that is a union of the individual streams.

As each stream reaches EOF, it will be automatically closed before bytes from the next stream are read.

Parameters
inputStreams:InputStream[]

streams to be pushed onto this stream.

Method Detail

addback to summary
public void add(InputStream in)

Add the given InputStream onto the end of the stream queue.

When the stream reaches EOF it will be automatically closed.

Parameters
in:InputStream

the stream to add; must not be null.

availableback to summary
public int available() throws IOException

Overrides java.io.InputStream.available.

Doc from java.io.InputStream.available.

Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking, which may be 0, or 0 when end of stream is detected. The read might be on the same thread or another thread. A single read or skip of this many bytes will not block, but may read or skip fewer bytes.

Note that while some implementations of InputStream will return the total number of bytes in the stream, many will not. It is never correct to use the return value of this method to allocate a buffer intended to hold all data in this stream.

A subclass's implementation of this method may choose to throw an IOException if this input stream has been closed by invoking the close() method.

Returns:int

an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking or 0 when it reaches the end of the input stream.

Annotations
@Override
Exceptions
IOException:
if an I/O error occurs.
closeback to summary
public void close() throws IOException

Overrides java.io.InputStream.close.

Implements java.io.Closeable.close.

Doc from java.io.InputStream.close.

Closes this input stream and releases any system resources associated with the stream.

Annotations
@Override
Exceptions
IOException:
if an I/O error occurs.
headback to summary
private InputStream head()
isEmptyback to summary
public boolean isEmpty()

Returns true if there are no more InputStreams in the stream queue.

If this method returns true then all read methods will signal EOF by returning -1, until another InputStream has been pushed into the queue with add(InputStream).

Returns:boolean

true if there are no more streams to read from.

popback to summary
private void pop() throws IOException
readback to summary
public int read() throws IOException

Implements abstract java.io.InputStream.read.

Doc from java.io.InputStream.read.

Reads the next byte of data from the input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

Returns:int

the next byte of data, or -1 if the end of the stream is reached.

Annotations
@Override
Exceptions
IOException:
if an I/O error occurs.
readback to summary
public int read(byte[] b, int off, int len) throws IOException

Overrides java.io.InputStream.read.

Doc from java.io.InputStream.read.

Reads up to len bytes of data from the input stream into an array of bytes. An attempt is made to read as many as len bytes, but a smaller number may be read. The number of bytes actually read is returned as an integer.

This method blocks until input data is available, end of file is detected, or an exception is thrown.

If len is zero, then no bytes are read and 0 is returned; otherwise, there is an attempt to read at least one byte. If no byte is available because the stream is at end of file, the value -1 is returned; otherwise, at least one byte is read and stored into b.

The first byte read is stored into element b[off], the next one into b[off+1], and so on. The number of bytes read is, at most, equal to len. Let k be the number of bytes actually read; these bytes will be stored in elements b[off] through b[off+k-1], leaving elements b[off+k] through b[off+len-1] unaffected.

In every case, elements b[0] through b[off-1] and elements b[off+len] through b[b.length-1] are unaffected.

Parameters
b:byte[]

the buffer into which the data is read.

off:int

the start offset in array b at which the data is written.

len:int

the maximum number of bytes to read.

Returns:int

the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.

Annotations
@Override
Exceptions
IOException:
If the first byte cannot be read for any reason other than end of file, or if the input stream has been closed, or if some other I/O error occurs.
skipback to summary
public long skip(long count) throws IOException

Overrides java.io.InputStream.skip.

Doc from java.io.InputStream.skip.

Skips over and discards n bytes of data from this input stream. The skip method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly 0. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. The actual number of bytes skipped is returned. If n is negative, the skip method for class InputStream always returns 0, and no bytes are skipped. Subclasses may handle the negative value differently.

Parameters
count:long

the number of bytes to be skipped.

Returns:long

the actual number of bytes skipped which might be zero.

Annotations
@Override
Exceptions
IOException:
if an I/O error occurs.