org.eclipse.swt.internal

Class Compatibility

java.lang.Object

org.eclipse.swt.internal.Compatibility

public final class Compatibility
extends Object

This class is a placeholder for utility methods commonly used on J2SE platforms but not supported on some J2ME profiles.

It is part of our effort to provide support for both J2SE and J2ME platforms.

IMPORTANT: some of the methods have been modified from their J2SE parents. Refer to the description of each method for specific changes.

• Exceptions thrown may differ since J2ME's set of exceptions is a subset of J2SE's one.
• The range of the mathematic functions is subject to change.

Constructor Summary

Constructors

Constructor and Description
Compatibility()

Method Summary

Modifier and Type	Method and Description
static int	ceil(int p, int q) Answers the most negative (i.e.
static void	exec(String[] prog, String[] envp, String workingDir) Execute prog[0] in a separate platform process if the underlying platform supports this.
static boolean	fileExists(String parent, String child) Answers whether the indicated file exists or not.
static String	getMessage(String key) Returns the NLS'ed message for the given argument.
static String	getMessage(String key, Object[] args)
static int	pow2(int n) Returns 2 raised to the power of the argument.
static int	round(int p, int q) Answers the result of rounding to the closest integer the number obtained by dividing the first argument p by the second argument q.

Methods inherited from class java.lang.Object

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

Constructor Detail

Compatibility

public Compatibility()

Method Detail

ceil

public static int ceil(int p,
                       int q)

Answers the most negative (i.e. closest to negative infinity) integer value which is greater than or equal to the number obtained by dividing the first argument p by the second argument q.

Parameters:

p - numerator

q - denominator (must be different from zero)

Returns:

the ceiling of the rational number p / q.

fileExists

public static boolean fileExists(String parent,
                                 String child)

Answers whether the indicated file exists or not.

Parameters:

parent - the file's parent directory

child - the file's name

Returns:

true if the file exists

round

public static int round(int p,
                        int q)

Answers the result of rounding to the closest integer the number obtained by dividing the first argument p by the second argument q.

IMPORTANT: the j2me version has an additional restriction on the arguments. p must be within the range 0 - 32767 (inclusive). q must be within the range 1 - 32767 (inclusive).

Parameters:

p - numerator

q - denominator (must be different from zero)

Returns:

the closest integer to the rational number p / q

pow2

public static int pow2(int n)

Returns 2 raised to the power of the argument.

Parameters:

n - an int value between 0 and 30 (inclusive)

Returns:

2 raised to the power of the argument

Throws:

IllegalArgumentException -

• ERROR_INVALID_RANGE - if the argument is not between 0 and 30 (inclusive)

exec

public static void exec(String[] prog,
                        String[] envp,
                        String workingDir)
                 throws IOException

Execute prog[0] in a separate platform process if the underlying platform supports this.

The new process inherits the environment of the caller.

Parameters:

prog - array containing the program to execute and its arguments

envp - array of strings, each element of which has environment variable settings in the format name=value

workingDir - the working directory of the new process, or null if the new process should inherit the working directory of the caller

Throws:

IOException - if the program cannot be executed

SecurityException - if the current SecurityManager disallows program execution

Since:

3.6

getMessage

public static String getMessage(String key)

Returns the NLS'ed message for the given argument. This is only being called from SWT.

Parameters:

key - the key to look up

Returns:

the message for the given key

See Also:

SWT.getMessage(String)

getMessage

public static String getMessage(String key,
                                Object[] args)