Package com.norconex.commons.lang

Class SystemUtil

java.lang.Object

com.norconex.commons.lang.SystemUtil

public final class SystemUtil
extends Object

System-related convenience methods.

Since:

2.0.0

Author:

Pascal Essiembre

Method Summary

Modifier and Type	Method	Description
static <T> T	callWithProperty(String name, String value, Callable<T> callable)	Executes the supplied Callable after setting the system property and then resets that system property.
static String	getEnvironment(String name)	Gets the value of the specified environment variable matching the exact name, or a supported variant.
static String	getEnvironmentOrProperty(String name)	Gets the environment variable or system property matching the exact name, or a supported variant.
static String	getProperty(String name)	Gets the value of the system property matching the exact name, or a supported variant.
static String	getPropertyOrEnvironment(String name)	Gets the system property or environment variable matching the exact name, or a supported variant.
static void	runWithProperty(String name, String value, Runnable runnable)	Executes the supplied Runnable after setting the system property and then resets that system property.

Methods inherited from class java.lang.Object

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

Method Details

runWithProperty

public static void runWithProperty(String name,
 String value,
 Runnable runnable)

Executes the supplied Runnable after setting the system property and then resets that system property. This method is synchronized to make sure setting the property does not affect other threads. The system property is restored to its original value (if any) after execution. Useful when the invoked code expects a system property that is configurable and may change from one thread to another.

null handling

This method is null-safe. If the runnable is null, invoking this method has no effect. If the property name is null, the runnable is invoked without setting any property beforehand. If the property value is null, it will temporary clear any existing system property with the same name (if any) for the duration of the execution.

Parameters:

name - system property name

value - system property value

runnable - code to run with the system property set

callWithProperty

public static <T> T callWithProperty(String name,
 String value,
 Callable<T> callable)
                              throws Exception

Executes the supplied Callable after setting the system property and then resets that system property. This method is synchronized to make sure setting the property does not affect other threads. The system property is restored to its original value (if any) after execution. Useful when the invoked code expects a system property that is configurable and may change from one thread to another.

null handling

This method is null-safe. If the callable is null, invoking this method returns null. If the property name is null, the runnable is invoked without setting any property beforehand. If the property value is null, it will temporary clear any existing system property with the same name (if any) for the duration of the execution.

Type Parameters:

T - class type of return value

Parameters:

name - system property name

value - system property value

callable - code to run with the system property set

Returns:

the callable return value

Throws:

Exception - any exception the callable may throw

getEnvironmentOrProperty

public static String getEnvironmentOrProperty(String name)

Gets the environment variable or system property matching the exact name, or a supported variant. Same as invoking getEnvironment(String) and if null, invoking getProperty(String).

Parameters:

name - property or environment name

Returns:

property or environment value

getPropertyOrEnvironment

public static String getPropertyOrEnvironment(String name)

Gets the system property or environment variable matching the exact name, or a supported variant. Same as invoking getProperty(String) and if null, invoking getEnvironment(String).

Parameters:

name - environment or property name

Returns:

environment or property value

getEnvironment

public static String getEnvironment(String name)

Gets the value of the specified environment variable matching the exact name, or a supported variant. First, it looks for a direct environment variable name match, as with System.getenv(String). If no matches are found, it will iterate through all environment variables names and compare them all with the requested name, but only after stripping all non alpha-numeric characters and ignoring case.

Parameters:

name - the name of the environment variable

Returns:

environment variable value

getProperty

public static String getProperty(String name)

Gets the value of the system property matching the exact name, or a supported variant. First, it looks for a direct property name match, as with System.getProperty(String). If no matches are found, it will iterate through all system property names and compare them all with the requested name, but only after stripping all non alpha-numeric characters and ignoring case.

Parameters:

name - the name of the system property

Returns:

system property value