File	Doc	Category	Size	Date	Package
SequenceInputStream.java	API Doc	Java SE 6 API	7219	Tue Jun 10 00:25:34 BST 2008	java.io

SequenceInputStream

• java.lang.Object
  • java.io.InputStream

Fields Summary
Enumeration	e
InputStream	in

Constructors Summary
public SequenceInputStream(Enumeration e) Initializes a newly created SequenceInputStream by remembering the argument, which must be an Enumeration that produces objects whose run-time type is InputStream. The input streams that are produced by the enumeration will be read, in order, to provide the bytes to be read from this SequenceInputStream. After each input stream from the enumeration is exhausted, it is closed by calling its close method. param e an enumeration of input streams. see java.util.Enumeration this.e = e; try { nextStream(); } catch (IOException ex) { // This should never happen throw new Error("panic"); }
public SequenceInputStream(InputStream s1, InputStream s2) Initializes a newly created SequenceInputStream by remembering the two arguments, which will be read in order, first s1 and then s2, to provide the bytes to be read from this SequenceInputStream. param s1 the first input stream to read. param s2 the second input stream to read. Vector v = new Vector(2); v.addElement(s1); v.addElement(s2); e = v.elements(); try { nextStream(); } catch (IOException ex) { // This should never happen throw new Error("panic"); }

Methods Summary
public int	available() Returns an estimate of the number of bytes that can be read (or skipped over) from the current underlying input stream without blocking by the next invocation of a method for the current underlying 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. This method simply calls {@code available} of the current underlying input stream and returns the result. return an estimate of the number of bytes that can be read (or skipped over) from the current underlying input stream without blocking or {@code 0} if this input stream has been closed by invoking its {@link #close()} method exception IOException if an I/O error occurs. since JDK1.1 if(in == null) { return 0; // no way to signal EOF from available() } return in.available();
public void	close() Closes this input stream and releases any system resources associated with the stream. A closed SequenceInputStream cannot perform input operations and cannot be reopened. If this stream was created from an enumeration, all remaining elements are requested from the enumeration and closed before the close method returns. exception IOException if an I/O error occurs. do { nextStream(); } while (in != null);
final void	nextStream() Continues reading in the next stream if an EOF is reached. if (in != null) { in.close(); } if (e.hasMoreElements()) { in = (InputStream) e.nextElement(); if (in == null) throw new NullPointerException(); } else in = null;
public int	read() Reads the next byte of data from this input stream. The 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 tries to read one character from the current substream. If it reaches the end of the stream, it calls the close method of the current substream and begins reading from the next substream. return the next byte of data, or -1 if the end of the stream is reached. exception IOException if an I/O error occurs. if (in == null) { return -1; } int c = in.read(); if (c == -1) { nextStream(); return read(); } return c;
public int	read(byte[] b, int off, int len) Reads up to len bytes of data from this input stream into an array of bytes. 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. The read method of SequenceInputStream tries to read the data from the current substream. If it fails to read any characters because the substream has reached the end of the stream, it calls the close method of the current substream and begins reading from the next substream. param b the buffer into which the data is read. param off the start offset in array b at which the data is written. param len the maximum number of bytes read. return int the number of bytes read. exception NullPointerException If b is null. exception IndexOutOfBoundsException If off is negative, len is negative, or len is greater than b.length - off exception IOException if an I/O error occurs. if (in == null) { return -1; } else if (b == null) { throw new NullPointerException(); } else if (off < 0 || len < 0 || len > b.length - off) { throw new IndexOutOfBoundsException(); } else if (len == 0) { return 0; } int n = in.read(b, off, len); if (n <= 0) { nextStream(); return read(b, off, len); } return n;