Package it.unimi.di.law.bubing.util

Class Util

java.lang.Object

it.unimi.di.law.bubing.util.Util

public class Util
extends java.lang.Object

Generic static utility method container.

Constructor Summary

Constructors

Constructor	Description
Util()

Method Summary

Modifier and Type	Method	Description
static java.io.File	createHierarchicalTempFile(java.io.File baseDirectory, int pathElements, java.lang.String prefix, java.lang.String suffix)	Creates a temporary file with a random hierachical path.
static boolean	parseBoolean(java.lang.String s)	Parses a Boolean value reliably, throwing an exception if the argument is not true or false (case insensitively).
static byte[]	readByteArray(java.io.ObjectInputStream s)	Reads a byte array prefixed by its length encoded using vByte.
static int	readVByte(java.io.InputStream is)	Decodes a natural number from an InputStream using vByte.
static byte[]	toByteArray(java.lang.String s)	Returns a byte-array representation of an ASCII string.
static ByteArrayList	toByteArrayList(java.lang.String s, ByteArrayList list)	Writes an ASCII string in a ByteArrayList.
static java.io.OutputStream	toOutputStream(java.lang.String s, java.io.OutputStream os)	Writes a string to an output stream, discarding higher order bits.
static java.lang.String	toString(byte[] byteArray)	Returns a string representation of an ASCII byte array.
static java.lang.String	toString(byte[] byteArray, int offset, int length)	Returns a string representation of an ASCII byte-array fragment.
static java.lang.String	toString(ByteArrayList byteArrayList)	Returns a string representation of an ASCII byte array.
static int	vByteLength(int x)	Returns the length of the vByte encoding of a natural number.
static void	writeByteArray(byte[] a, java.io.ObjectOutputStream s)	Writes a byte array prefixed by its length encoded using vByte.
static int	writeVByte(int x, java.io.OutputStream os)	Encodes a natural number to an OutputStream using vByte.

Methods inherited from class java.lang.Object

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

Constructor Detail

Util

public Util()

Method Detail

parseBoolean

public static boolean parseBoolean(java.lang.String s)

Parses a Boolean value reliably, throwing an exception if the argument is not true or false (case insensitively).

Parameters:

s - a string containing true or false.

Returns:

true or false, depending on the content of s.

createHierarchicalTempFile

public static java.io.File createHierarchicalTempFile(java.io.File baseDirectory,
                                                      int pathElements,
                                                      java.lang.String prefix,
                                                      java.lang.String suffix)
                                               throws java.io.IOException

Creates a temporary file with a random hierachical path.

A random hierarchical path of n path elements is a sequence of n directories of two hexadecimal digits each, followed by a filename created by File.createTempFile(String, String, File).

This method creates an empty file having a random hierarchical path of the specified number of path elements under a given base directory, creating all needed directories along the hierarchical path (whereas the base directory is expected to already exist).

Parameters:

baseDirectory - the base directory (it must exist).

pathElements - the number of path elements (filename excluded), must be in [0,8]

prefix - will be passed to File.createTempFile(String, String, File)

suffix - will be passed to File.createTempFile(String, String, File)

Returns:

the temporary file.

Throws:

java.io.IOException

vByteLength

public static final int vByteLength(int x)

Returns the length of the vByte encoding of a natural number.

Parameters:

x - a natural number.

Returns:

the length of the vByte encoding of x.

writeVByte

public static int writeVByte(int x,
                             java.io.OutputStream os)
                      throws java.io.IOException

Encodes a natural number to an OutputStream using vByte.

Parameters:

x - a natural number.

os - an output stream.

Returns:

the number of bytes written.

Throws:

java.io.IOException

readVByte

public static int readVByte(java.io.InputStream is)
                     throws java.io.IOException

Decodes a natural number from an InputStream using vByte.

Parameters:

is - an input stream.

Returns:

a natural number decoded from is using vByte.

Throws:

java.io.IOException

writeByteArray

public static final void writeByteArray(byte[] a,
                                        java.io.ObjectOutputStream s)
                                 throws java.io.IOException

Writes a byte array prefixed by its length encoded using vByte.

Parameters:

a - the array to be written.

s - the stream where the array should be written.

Throws:

java.io.IOException

readByteArray

public static final byte[] readByteArray(java.io.ObjectInputStream s)
                                  throws java.io.IOException

Reads a byte array prefixed by its length encoded using vByte.

Parameters:

s - the stream from which the array should be read.

Returns:

the array.

Throws:

java.io.IOException

toByteArray

public static byte[] toByteArray(java.lang.String s)

Returns a byte-array representation of an ASCII string.

This method is significantly faster than those relying on character encoders, and it allocates just one object—the resulting byte array.

Parameters:

s - an ASCII string.

Returns:

a byte-array representation of s.

Throws:

java.lang.AssertionError - if assertions are enabled and some character of s is not ASCII.

toOutputStream

public static java.io.OutputStream toOutputStream(java.lang.String s,
                                                  java.io.OutputStream os)
                                           throws java.io.IOException

Writes a string to an output stream, discarding higher order bits.

This method is significantly faster than those relying on character encoders, and it does not allocate any object.

Parameters:

s - a string.

os - an output stream.

Returns:

os.

Throws:

java.lang.AssertionError - if assertions are enabled and some character of s does not fit a byte.

java.io.IOException

toByteArrayList

public static ByteArrayList toByteArrayList(java.lang.String s,
                                            ByteArrayList list)

Writes an ASCII string in a ByteArrayList.

Parameters:

s - an ASCII string.

list - a byte list that will contain the byte representation of s.

Returns:

list.

Throws:

java.lang.AssertionError - if assertions are enabled and some character of s is not ASCII.

toString

public static java.lang.String toString(ByteArrayList byteArrayList)

Returns a string representation of an ASCII byte array.

This method is significantly faster than those relying on character encoders, and it allocates just one object—the resulting string.

Parameters:

byteArrayList - an ASCII byte-array list.

Returns:

a string representation of byteArrayList.

Throws:

java.lang.AssertionError - if assertions are enabled and some character of byteArrayList is not ASCII.

toString

public static java.lang.String toString(byte[] byteArray)

Returns a string representation of an ASCII byte array.

This method is significantly faster than those relying on character encoders, and it allocates just one object—the resulting string.

Parameters:

byteArray - an ASCII byte array.

Returns:

a string representation of byteArray.

Throws:

java.lang.AssertionError - if assertions are enabled and some character of byteArray is not ASCII.

toString

public static java.lang.String toString(byte[] byteArray,
                                        int offset,
                                        int length)

Returns a string representation of an ASCII byte-array fragment.

This method is significantly faster than those relying on character encoders, and it allocates just one object—the resulting string.

Parameters:

byteArray - an ASCII byte array.

Returns:

a string representation of byteArray.

Throws:

java.lang.AssertionError - if assertions are enabled and some character of byteArray is not ASCII.