saker.util Documentation TaskDoc JavaDoc Packages
public class ConcatInputStream extends InputStream
Input stream class for concatenating the data of multiple input streams into one stream.

Important: This class doesn't close the streams that were passed to it. Each stream should be closed by the caller after the ConcatInputStream instance is closed.

This stream takes multiple InputStreams during its construction, and it will iterate over them when read operations are performed.

When a reading operation is performed, the class will try to read from the first input stream. When a stream returns zero bytes from a read operation, the class will move to the next stream and try reading from that. This repeats until no more streams are available, in which case the class will return end of stream for the reading operations.

This input stream class is not thread safe.

Constructors
public
ConcatInputStream(Iterable<extends InputStream> inputstreams)
Creates a new instance for the given input streams.
public
ConcatInputStream(Iterator<extends InputStream> streamiterator)
Creates a new instance for the given input streams specified by an iterator.
public
Creates a new instance for the given input streams.
Methods
public int
Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next invocation of a method for this input stream.
public void
Closes this input stream and releases any system resources associated with the stream.
public int
Reads the next byte of data from the input stream.
public int
read(byte[] b, int off, int len)
Reads up to len bytes of data from the input stream into an array of bytes.
public long
skip(long n)
Skips over and discards n bytes of data from this input stream.
public ConcatInputStream(Iterable<extends InputStream> inputstreams) throws NullPointerException
Creates a new instance for the given input streams.

null InputStreams in the argument iterable will be skipped.

inputstreamsAn iterable of input streams.
NullPointerExceptionIf the argument is null.
public ConcatInputStream(Iterator<extends InputStream> streamiterator) throws NullPointerException
Creates a new instance for the given input streams specified by an iterator.

null InputStreams in the argument iterator will be skipped.

streamiteratorAn iterator for input streams.
NullPointerExceptionIf the iterator is null.
public ConcatInputStream(InputStream... inputstreams) throws NullPointerException
Creates a new instance for the given input streams.

Modifying the argument array externally may result in incorrect operation.

null InputStreams in the argument array will be skipped.

inputstreamsThe input streams.
NullPointerExceptionIf the argument array is null.
public int available() throws IOException
Overridden from: InputStream
Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next invocation of a method for this input stream. The next invocation might be 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' implementation of this method may choose to throw an IOException if this input stream has been closed by invoking the InputStream.close() method.

The available method for class InputStream always returns 0.

This method should be overridden by subclasses.

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.
IOExceptionif an I/O error occurs.
public void close() throws IOException
Overridden from: InputStream
Closes this input stream and releases any system resources associated with the stream.

The close method of InputStream does nothing.

IOExceptionif an I/O error occurs.
public int read() throws IOException
Overridden from: InputStream
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.

A subclass must provide an implementation of this method.

the next byte of data, or -1 if the end of the stream is reached.
IOExceptionif an I/O error occurs.
public int read(byte[] b, int off, int len) throws IOException
Overridden from: InputStream
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] and elements b[off+len] through b[b.length-1] are unaffected.

The read(b, off, len) method for class InputStream simply calls the method read() repeatedly. If the first such call results in an IOException, that exception is returned from the call to the read(b, off, len) method. If any subsequent call to read() results in a IOException, the exception is caught and treated as if it were end of file; the bytes read up to that point are stored into b and the number of bytes read before the exception occurred is returned. The default implementation of this method blocks until the requested amount of input data len has been read, end of file is detected, or an exception is thrown. Subclasses are encouraged to provide a more efficient implementation of this method.

bthe buffer into which the data is read.
offthe start offset in array b at which the data is written.
lenthe maximum number of bytes to read.
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.
IOExceptionIf 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.
public long skip(long n) throws IOException
Overridden from: InputStream
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.

The skip method of this class creates a byte array and then repeatedly reads into it until n bytes have been read or the end of the stream has been reached. Subclasses are encouraged to provide a more efficient implementation of this method. For instance, the implementation may depend on the ability to seek.

nthe number of bytes to be skipped.
the actual number of bytes skipped.
IOExceptionif the stream does not support seek, or if some other I/O error occurs.