PushbackInputStream JDK 1.6)

Methods

public int available () throws IOException [Overrides FilterInputStream]

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.

publicsynchronized void close () throws IOException [Overrides FilterInputStream]

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

publicsynchronized void mark (int readlimit) [Overrides FilterInputStream]

Marks the current position in this input stream.

public boolean markSupported () [Overrides FilterInputStream]

Tests if this input stream supports the mark and reset methods, which it does not.

Tests if this input stream supports the mark and
reset methods, which it does not.
Returns: false, since this class does not support the mark and reset methods.
See Also: InputStream.mark(int), InputStream.reset(),

public int read () throws IOException [Overrides FilterInputStream] [Specified in InputStream]

Reads the next byte of data from this input stream.

Reads the next byte of data from this 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.

This method returns the most recently pushed-back byte, if there is one, and otherwise calls the read method of its underlying input stream and returns whatever value that method returns.
Returns: the next byte of data, or -1 if the end of the stream has been reached.
Throws:
- IOException - if this input stream has been closed by invoking its {@link #close()} method, or an I/O error occurs.
See Also: InputStream.read(),

public int read (byte[] b) throws IOException [Inherited From FilterInputStream]

Reads up to byte.length bytes of data from this input stream into an array of bytes.

Reads up to byte.length bytes of data from this input stream into an array of bytes. This method blocks until some input is available.

This method simply performs the call read(b, 0, b.length) and returns the result. It is important that it does not do in.read(b) instead; certain subclasses of FilterInputStream depend on the implementation strategy actually used.
Returns: 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.
Parameters:
- b - the buffer into which the data is read.
Throws:
- IOException - if an I/O error occurs.
See Also: FilterInputStream.read(byte[], int, int),

public int read (byte[] b, int off, int len) throws IOException [Overrides FilterInputStream]

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

Reads up to len bytes of data from this input stream into
an array of bytes. This method first reads any pushed-back bytes; after
that, if fewer than len bytes have been read then it
reads from the underlying input stream. If len is not zero, the method
blocks until at least 1 byte of input is available; otherwise, no
bytes are read and 0 is returned.
Returns: 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.
Parameters:
- b - the buffer into which the data is read.
- off - the start offset in the destination array b
- len - the maximum number of bytes read.
Throws:
- NullPointerException - If b is null.
- IndexOutOfBoundsException - If off is negative, len is negative, or len is greater than b.length - off
- IOException - if this input stream has been closed by invoking its {@link #close()} method, or an I/O error occurs.
See Also: InputStream.read(byte[], int, int),

publicsynchronized void reset () throws IOException [Overrides FilterInputStream]

Repositions this stream to the position at the time the mark method was last called on this input stream.

The method reset for class PushbackInputStream does nothing except throw an IOException.
Throws:
- IOException - if this method is invoked.
See Also: InputStream.mark(int), IOException,

public long skip (long n) throws IOException [Overrides FilterInputStream]

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

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 zero. If n is negative, no bytes are skipped.

The skip method of PushbackInputStream first skips over the bytes in the pushback buffer, if any. It then calls the skip method of the underlying input stream if more bytes need to be skipped. The actual number of bytes skipped is returned.
Returns: {@inheritDoc}
Parameters:
- n - {@inheritDoc}
Throws:
- IOException - if the stream does not support seek, or the stream has been closed by invoking its {@link #close()} method, or an I/O error occurs.
Since: 1.2
See Also: FilterInputStream.in, InputStream.skip(long n),

public void unread (byte[] b) throws IOException

Pushes back an array of bytes by copying it to the front of the pushback buffer.

Pushes back an array of bytes by copying it to the front of the
pushback buffer. After this method returns, the next byte to be read
will have the value b[0], the byte after that will have the
value b[1], and so forth.
Parameters:
- b - the byte array to push back
Throws:
- IOException - If there is not enough room in the pushback buffer for the specified number of bytes, or this input stream has been closed by invoking its {@link #close()} method.
Since: JDK1.1

public void unread (byte[] b, int off, int len) throws IOException

Pushes back a portion of an array of bytes by copying it to the front of the pushback buffer.

Pushes back a portion of an array of bytes by copying it to the front
of the pushback buffer. After this method returns, the next byte to be
read will have the value b[off], the byte after that will
have the value b[off+1], and so forth.
Parameters:
- b - the byte array to push back.
- off - the start offset of the data.
- len - the number of bytes to push back.
Throws:
- IOException - If there is not enough room in the pushback buffer for the specified number of bytes, or this input stream has been closed by invoking its {@link #close()} method.
Since: JDK1.1

public void unread (int b) throws IOException

Pushes back a byte by copying it to the front of the pushback buffer.

Pushes back a byte by copying it to the front of the pushback buffer.
After this method returns, the next byte to be read will have the value
(byte)b.
Parameters:
- b - the int value whose low-order byte is to be pushed back.
Throws:
- IOException - If there is not enough room in the pushback buffer for the byte, or this input stream has been closed by invoking its {@link #close()} method.