uk.ac.starlink.util

Class IOUtils

java.lang.Object

uk.ac.starlink.util.IOUtils

public class IOUtils
extends java.lang.Object

Provides static methods which do miscellaneous input/output tasks.

Method Summary

Modifier and Type	Method and Description
static void	copy(java.io.InputStream in, java.io.OutputStream out) Copies all the bytes from a given input stream to a given output stream.
static byte[]	getLineSeparatorBytes() Returns the platform's line separator as a byte array given the platform's default encoding.
static java.lang.String	getResourceContents(java.lang.Class<?> clazz, java.lang.String name, java.util.logging.Level level) Reads a static resource and returns the contents as a string.
static void	println(java.io.OutputStream out, java.lang.String line) Writes a string to an output stream followed by a new line.
static byte[]	readBytes(java.io.InputStream in, int maxLeng) Reads a number of bytes from a stream.
static void	skip(java.io.InputStream strm, long nskip) Skips over a number of bytes in an InputStream This is implemented using InputStream.skip(long) but differs from it in that it guarantees to skip the bytes as specified, or to throw an exception.
static void	skipBytes(java.io.DataInput strm, long nskip) Skips over a number of bytes in a DataInput.

Methods inherited from class java.lang.Object

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

Method Detail

skipBytes

public static void skipBytes(java.io.DataInput strm,
                             long nskip)
                      throws java.io.IOException

Skips over a number of bytes in a DataInput. This is implemented using DataInput.skipBytes(int) but differs from it in that it guarantees to skip the bytes as specified, or to throw an exception.

Parameters:

strm - the stream to skip through

nskip - the number of bytes to skip

Throws:

java.io.EOFException - if the end of file is reached

java.io.IOException - if an I/O error occurs

java.lang.IllegalArgumentException - if nskip<0

skip

public static void skip(java.io.InputStream strm,
                        long nskip)
                 throws java.io.IOException

Skips over a number of bytes in an InputStream This is implemented using InputStream.skip(long) but differs from it in that it guarantees to skip the bytes as specified, or to throw an exception.

Parameters:

strm - the stream to skip through

nskip - the number of bytes to skip

Throws:

java.io.EOFException - if the end of file is reached

java.io.IOException - if an I/O error occurs

java.lang.IllegalArgumentException - if nskip<0

getResourceContents

public static java.lang.String getResourceContents(java.lang.Class<?> clazz,
                                                   java.lang.String name,
                                                   java.util.logging.Level level)

Reads a static resource and returns the contents as a string. The resource is read using clazz.getResourceAsStream(name) and is assumed to have ASCII content. The result is cached so that subsequent calls will return the same value. If it can't be read, "?" is returned, and a message is written through the logging system at the requested level. This is intended for short files such as version strings.

Parameters:

clazz - class defining relative location of resource

name - resource name relative to clazz

level - logging level for failure; if null a default value is used (currently WARNING)

Returns:

resource content string

See Also:

Class.getResourceAsStream(java.lang.String)

println

public static void println(java.io.OutputStream out,
                           java.lang.String line)
                    throws java.io.IOException

Writes a string to an output stream followed by a new line. Unlike PrintStream.println(), an IOException may be thrown.

Parameters:

out - destination stream

line - line to write

Throws:

java.io.IOException

getLineSeparatorBytes

public static byte[] getLineSeparatorBytes()

Returns the platform's line separator as a byte array given the platform's default encoding. May or may not be equal to {'\n'}.

Returns:

line separator byte sequence

copy

public static void copy(java.io.InputStream in,
                        java.io.OutputStream out)
                 throws java.io.IOException

Copies all the bytes from a given input stream to a given output stream. Neither stream is closed following the copy.

Parameters:

in - source

out - destination

Throws:

java.io.IOException

readBytes

public static byte[] readBytes(java.io.InputStream in,
                               int maxLeng)
                        throws java.io.IOException

Reads a number of bytes from a stream. The specified number of bytes or the whole of the file is read, whichever is shorter.

Parameters:

in - input stream

maxLeng - maximum number of bytes to read

Returns:

buffer of bytes containing maxLeng bytes read from in, or fewer if the stream ended early

Throws:

java.io.IOException