vona.compat

Class Compat

java.lang.Object

vona.compat.Compat

public class Compat
extends java.lang.Object

Vona's java compatibility utilities.

Copyright (C) 2005, Marsette A. Vona, III

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

Author:

Marsette (Marty) A. Vona, III

Field Summary

Fields

Modifier and Type	Field and Description
private static boolean	checked15 Memo for is15().
private static boolean	checked16 Memo for is16().
private static boolean	checkedLinux Memo for isLinux().
private static boolean	checkedOSX Memo for isOSX().
private static boolean	checkedWindows Memo for isWindows().
static java.lang.ClassLoader	classLoader The class loader to use, if null then Class.forName().
private static java.lang.String	cvsid CVS id.
private static boolean	osLinux Memo for isLinux().
private static boolean	osOSX Memo for isOSX().
private static boolean	osWindows Memo for isWindows().
private static java.io.File	tempDir Memo for getTempDir().
private static boolean	version15 Memo for is15().
private static boolean	version16 Memo for is16().

Constructor Summary

Constructors

Constructor and Description
Compat()

Method Summary

Methods

Modifier and Type	Method and Description
static java.lang.Object	construct(java.lang.String className) Covers construct(String, Object[]), calls the no-arg constructor.
static java.lang.Object	construct(java.lang.String className, java.lang.Object[] arg) Covers construct(String, Object[], String[]), infers argument types.
static java.lang.Object	construct(java.lang.String className, java.lang.Object[] arg, java.lang.String[] argTypeName) Attempt to make an instance of a class that may or may not exist and which may or may not have a constructor matching the specified arguments.
static java.lang.Object	constructSafely(java.lang.String className) Covers construct(String), swallows exceptions, returns null on failure.
static java.lang.Object	constructSafely(java.lang.String className, java.lang.Object[] arg) Covers construct(String, Object[]), swallows exceptions, returns null on failure.
static java.lang.Object	constructSafely(java.lang.String className, java.lang.Object[] arg, java.lang.String[] argTypeName) Covers construct(String, Object[], String[]), swallows exceptions, returns null on failure.
static void	dumpPlatformProperties() dumpPlatformProperties(PrintStream) to System.out.
static void	dumpPlatformProperties(java.io.PrintStream out) Dump the platform identifying system properties.
static java.lang.String	getPropertySafely(java.lang.String key) Get a system property, handling any runtime exception.
static java.lang.String	getSimpleName(java.lang.Class clazz) Get the simple name of a class.
static java.io.File	getTempDir() Get the temp dir on this platform.
static java.lang.Object	invoke(java.lang.Object obj, java.lang.String methodName) Covers invoke(Object, String, Object[]), uses no arguments.
static java.lang.Object	invoke(java.lang.Object obj, java.lang.String methodName, java.lang.Object[] arg) Covers invoke(Object, String, Object[], String[]), infers argument types.
static java.lang.Object	invoke(java.lang.Object obj, java.lang.String methodName, java.lang.Object[] arg, java.lang.String[] argTypeName) Covers invoke(String, Object, String, Object[], String[]), infers class name from obj.
protected static java.lang.Object	invoke(java.lang.String className, java.lang.Object obj, java.lang.String methodName, java.lang.Object[] arg, java.lang.String[] argTypeName) Attempt to call a static or instance method that may or may not exist.
static java.lang.Object	invoke(java.lang.String className, java.lang.String methodName) Covers invoke(String, String, Object[]), uses no arguments.
static java.lang.Object	invoke(java.lang.String className, java.lang.String methodName, java.lang.Object[] arg) Covers invoke(String, String, Object[], String[]), infers argument types.
static java.lang.Object	invoke(java.lang.String className, java.lang.String methodName, java.lang.Object[] arg, java.lang.String[] argTypeName) Covers invoke(String, Object, String, Object[], String[]), uses null obj, thus calling a static method.
static java.lang.Object	invokeSafely(java.lang.Object obj, java.lang.String methodName) Covers invoke(Object, String), swallows exceptions, returns null on failure.
static java.lang.Object	invokeSafely(java.lang.Object obj, java.lang.String methodName, java.lang.Object[] arg) Covers invoke(Object, String, Object[]), swallows exceptions, returns null on failure.
static java.lang.Object	invokeSafely(java.lang.Object obj, java.lang.String methodName, java.lang.Object[] arg, java.lang.String[] argTypeName) Covers invoke(Object, String, Object[], String[]), swallows exceptions, returns null on failure.
static java.lang.Object	invokeSafely(java.lang.String className, java.lang.String methodName) Covers invoke(String, String) swallows exceptions, returns null on failure.
static java.lang.Object	invokeSafely(java.lang.String className, java.lang.String methodName, java.lang.Object[] arg) Covers invoke(String, String, Object[]) swallows exceptions, returns null on failure.
static java.lang.Object	invokeSafely(java.lang.String className, java.lang.String methodName, java.lang.Object[] arg, java.lang.String[] argTypeName) Covers invoke(String, String, Object[], String[]) swallows exceptions, returns null on failure.
static boolean	is15() Check if we're running with a 1.5 JRE.
static boolean	is16() Check if we're running with a 1.6 JRE.
static boolean	isLinux() Check if we're running on Linux.
static boolean	isOSX() Check if we're running on OS X.
static boolean	isWindows() Check if we're running on Windows.
static void	main(java.lang.String[] arg) Test driver dumps dbg to System.out.
protected static java.lang.Class[]	makeArgType(java.lang.Object[] arg, java.lang.String[] argTypeName) Collect argument types.
static void	setLocationByPlatform(java.awt.Window window, boolean value) Request a change to the location-by-platform status of a frame.

Methods inherited from class java.lang.Object

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

Field Detail

cvsid

private static final java.lang.String cvsid

CVS id.

See Also:

Constant Field Values

checkedLinux

private static boolean checkedLinux

Memo for isLinux().

osLinux

private static boolean osLinux

Memo for isLinux().

checkedWindows

private static boolean checkedWindows

Memo for isWindows().

osWindows

private static boolean osWindows

Memo for isWindows().

checkedOSX

private static boolean checkedOSX

Memo for isOSX().

osOSX

private static boolean osOSX

Memo for isOSX().

checked15

private static boolean checked15

Memo for is15().

version15

private static boolean version15

Memo for is15().

checked16

private static boolean checked16

Memo for is16().

version16

private static boolean version16

Memo for is16().

tempDir

private static java.io.File tempDir

Memo for getTempDir().

.

classLoader

public static java.lang.ClassLoader classLoader

The class loader to use, if null then Class.forName().

Constructor Detail

Compat

public Compat()

Method Detail

construct

public static java.lang.Object construct(java.lang.String className)
                                  throws java.lang.reflect.InvocationTargetException

Covers construct(String, Object[]), calls the no-arg constructor.

Throws:

java.lang.reflect.InvocationTargetException

constructSafely

public static java.lang.Object constructSafely(java.lang.String className)

Covers construct(String), swallows exceptions, returns null on failure.

construct

public static java.lang.Object construct(java.lang.String className,
                         java.lang.Object[] arg)
                                  throws java.lang.reflect.InvocationTargetException

Covers construct(String, Object[], String[]), infers argument types.

Throws:

java.lang.reflect.InvocationTargetException

constructSafely

public static java.lang.Object constructSafely(java.lang.String className,
                               java.lang.Object[] arg)

Covers construct(String, Object[]), swallows exceptions, returns null on failure.

construct

public static java.lang.Object construct(java.lang.String className,
                         java.lang.Object[] arg,
                         java.lang.String[] argTypeName)
                                  throws java.lang.reflect.InvocationTargetException

Attempt to make an instance of a class that may or may not exist and which may or may not have a constructor matching the specified arguments.

Parameters:

className - the full name (i.e. with package) of the class to instantiate, not null. Resolved to a class via Class.forName(), unless classLoader is non-null.

arg - see makeArgType(java.lang.Object[], java.lang.String[])

argTypeName - see makeArgType(java.lang.Object[], java.lang.String[])

Returns:

an instance of the requested class

Throws:

java.lang.reflect.InvocationTargetException - wrapping another exception if the class was not found or was inaccessible, did not have a matching constructor, an argument type was not found, or the constructor threw an exception

constructSafely

public static java.lang.Object constructSafely(java.lang.String className,
                               java.lang.Object[] arg,
                               java.lang.String[] argTypeName)

Covers construct(String, Object[], String[]), swallows exceptions, returns null on failure.

makeArgType

protected static java.lang.Class[] makeArgType(java.lang.Object[] arg,
                            java.lang.String[] argTypeName)
                                        throws java.lang.reflect.InvocationTargetException

Collect argument types.

Parameters:

arg - the list of arguments, if null a zero-length argument list is implied. If non-null, all elements must be non-null.

argTypeName - the full names of the types of the arguments, to be resolved by Class.forName(), unless classLoader is non-null. If argTypeName is null the argument types will be inferred from the types of the elements of arg, but in that case all the latter must be non-null (arg itself may still be null, indicating no arguments)

Returns:

the types of the arguments

Throws:

java.lang.reflect.InvocationTargetException - wrapping a ClassNotFoundException if any of the argument classes could not be found

invoke

public static java.lang.Object invoke(java.lang.Object obj,
                      java.lang.String methodName)
                               throws java.lang.reflect.InvocationTargetException

Covers invoke(Object, String, Object[]), uses no arguments.

Throws:

java.lang.reflect.InvocationTargetException

invokeSafely

public static java.lang.Object invokeSafely(java.lang.Object obj,
                            java.lang.String methodName)

Covers invoke(Object, String), swallows exceptions, returns null on failure.

invoke

public static java.lang.Object invoke(java.lang.Object obj,
                      java.lang.String methodName,
                      java.lang.Object[] arg)
                               throws java.lang.reflect.InvocationTargetException

Covers invoke(Object, String, Object[], String[]), infers argument types.

Throws:

java.lang.reflect.InvocationTargetException

invokeSafely

public static java.lang.Object invokeSafely(java.lang.Object obj,
                            java.lang.String methodName,
                            java.lang.Object[] arg)

Covers invoke(Object, String, Object[]), swallows exceptions, returns null on failure.

invoke

public static java.lang.Object invoke(java.lang.Object obj,
                      java.lang.String methodName,
                      java.lang.Object[] arg,
                      java.lang.String[] argTypeName)
                               throws java.lang.reflect.InvocationTargetException

Covers invoke(String, Object, String, Object[], String[]), infers class name from obj.

Throws:

java.lang.reflect.InvocationTargetException

invokeSafely

public static java.lang.Object invokeSafely(java.lang.Object obj,
                            java.lang.String methodName,
                            java.lang.Object[] arg,
                            java.lang.String[] argTypeName)

Covers invoke(Object, String, Object[], String[]), swallows exceptions, returns null on failure.

invoke

protected static java.lang.Object invoke(java.lang.String className,
                      java.lang.Object obj,
                      java.lang.String methodName,
                      java.lang.Object[] arg,
                      java.lang.String[] argTypeName)
                                  throws java.lang.reflect.InvocationTargetException

Attempt to call a static or instance method that may or may not exist.

Parameters:

className - the full name (i.e. with package) of the class on which to call the method. If null then inferred from obj, which must not be null in that case. Resolved to a class via Class.forName(), unless classLoader is non-null.

obj - the object against which to call an instance method. If null then a static method is called, and in that case className must be non-null. If both className and obj are specified they must be consistent.

methodName - the name of the method to call, not null

arg - see makeArgType(java.lang.Object[], java.lang.String[])

argTypeName - see makeArgType(java.lang.Object[], java.lang.String[])

Returns:

the return value of the method

Throws:

java.lang.reflect.InvocationTargetException - wrapping another exception if the class was not found or was inaccessible, did not have a matching method, an argument type was not found, or the method threw an exception

invoke

public static java.lang.Object invoke(java.lang.String className,
                      java.lang.String methodName)
                               throws java.lang.reflect.InvocationTargetException

Covers invoke(String, String, Object[]), uses no arguments.

Throws:

java.lang.reflect.InvocationTargetException

invokeSafely

public static java.lang.Object invokeSafely(java.lang.String className,
                            java.lang.String methodName)

Covers invoke(String, String) swallows exceptions, returns null on failure.

invoke

public static java.lang.Object invoke(java.lang.String className,
                      java.lang.String methodName,
                      java.lang.Object[] arg)
                               throws java.lang.reflect.InvocationTargetException

Covers invoke(String, String, Object[], String[]), infers argument types.

Throws:

java.lang.reflect.InvocationTargetException

invokeSafely

public static java.lang.Object invokeSafely(java.lang.String className,
                            java.lang.String methodName,
                            java.lang.Object[] arg)

Covers invoke(String, String, Object[]) swallows exceptions, returns null on failure.

invoke

public static java.lang.Object invoke(java.lang.String className,
                      java.lang.String methodName,
                      java.lang.Object[] arg,
                      java.lang.String[] argTypeName)
                               throws java.lang.reflect.InvocationTargetException

Covers invoke(String, Object, String, Object[], String[]), uses null obj, thus calling a static method.

Throws:

java.lang.reflect.InvocationTargetException

invokeSafely

public static java.lang.Object invokeSafely(java.lang.String className,
                            java.lang.String methodName,
                            java.lang.Object[] arg,
                            java.lang.String[] argTypeName)

Covers invoke(String, String, Object[], String[]) swallows exceptions, returns null on failure.

isLinux

public static boolean isLinux()

Check if we're running on Linux.

Memoized.

Returns:

true iff we're running on Linux

isWindows

public static boolean isWindows()

Check if we're running on Windows.

Memoized.

Returns:

true iff we're running on Windows

isOSX

public static boolean isOSX()

Check if we're running on OS X.

Memoized.

Returns:

true iff we're running on OS X

is15

public static boolean is15()

Check if we're running with a 1.5 JRE.

Memoized.

Returns:

true iff we're running with a 1.5 JRE

is16

public static boolean is16()

Check if we're running with a 1.6 JRE.

Memoized.

Returns:

true iff we're running with a 1.6 JRE

getSimpleName

public static java.lang.String getSimpleName(java.lang.Class clazz)

Get the simple name of a class.

This is a new API in 1.5.

The simple name is the class name without any package.

Parameters:

clazz - the Class

Returns:

the simple name of clazz

setLocationByPlatform

public static void setLocationByPlatform(java.awt.Window window,
                         boolean value)

Request a change to the location-by-platform status of a frame.

This is a new API in 1.5.

If the runtime JRE is not 1.5 then this call will have no effect.

Parameters:

window - the window for which to change the location-by-platform status

value - the new status

dumpPlatformProperties

public static void dumpPlatformProperties()

dumpPlatformProperties(PrintStream) to System.out.

dumpPlatformProperties

public static void dumpPlatformProperties(java.io.PrintStream out)

Dump the platform identifying system properties.

Parameters:

out - the dump destination

getPropertySafely

public static java.lang.String getPropertySafely(java.lang.String key)

Get a system property, handling any runtime exception.

Parameters:

key - the property key

Returns:

the property value or an error message

getTempDir

public static java.io.File getTempDir()

Get the temp dir on this platform.

Attempts to return the persistent temp dir (i.e. /var/tmp) when possible.

Attempts to verify that the returned directory exists and is writeable; however if the runtime security manager doesn't allow this to be determined it makes a best guess.

Returns:

the temp dir on this platform

main

public static void main(java.lang.String[] arg)

Test driver dumps dbg to System.out.