SystemUtil (checker-framework 3.6.0 API)

java.lang.Object
- org.checkerframework.javacutil.SystemUtil

```
public class SystemUtil
extends Object
```
This file contains basic utility functions.

Constructor Summary

Constructors
Constructor and Description

SystemUtil()

Constructors
Constructor and Description
`SystemUtil()`

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static <T> T[]`	`concatenate(T[] array1, T... array2)` Concatenates two arrays.
`static boolean`	`getBooleanSystemProperty(String key)` Return true if the system property is set to "true".
`static boolean`	`getBooleanSystemProperty(String key, boolean defaultValue)` Return its boolean value if the system property is set.
`static int`	`getJreVersion()` Returns the major JRE version.
`static @Nullable String`	`getReleaseValue(ProcessingEnvironment env)` Returns the release value passed to the compiler or null if release was not passed.
`static @Nullable String`	`getToolsJar()` Returns the pathname to the tools.jar file, or null if it does not exist.
`static String`	`join(CharSequence delimiter, @Nullable Iterable<?> values)` Returns a new String composed of the string representations of the elements joined together with a copy of the specified delimiter.
`static <T> String`	`join(CharSequence delimiter, T[] objs)` Returns a new String composed of the string representations of the elements joined together with a copy of the specified delimiter.
`static String`	`joinLines(@Nullable Iterable<? extends Object> v)` Concatenate the string representations of the objects, placing the system-specific line separator between them.
`static <T> String`	`joinLines(T... a)` Concatenate the string representations of the objects, placing the system-specific line separator between them.
`static List<String>`	`readFile(File argFile)` Return a list of Strings, one per line of the file.
`static void`	`sleep(long millis)` Like Thread.sleep, but does not throw any exceptions, so it is easier for clients to use.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - SystemUtil
```
public SystemUtil()
```
- Method Detail
  - readFile
```
public static List<String> readFile(File argFile)
                             throws IOException
```
    Return a list of Strings, one per line of the file.
    
    Parameters:
    
    argFile - argument file
    
    Returns:
    
    a list of Strings, one per line of the file
    
    Throws:
    
    IOException - when reading the argFile
  - join
```
public static <T> String join(CharSequence delimiter,
                              T[] objs)
```
    Returns a new String composed of the string representations of the elements joined together with a copy of the specified delimiter.
    
    Type Parameters:
    
    T - the type of array elements
    
    Parameters:
    
    delimiter - the delimiter that separates each element
    
    objs - the values whose string representations to join together
    
    Returns:
    
    a new string that concatenates the string representations of the elements
  - join
```
public static String join(CharSequence delimiter,
                          @Nullable Iterable<?> values)
```
    Returns a new String composed of the string representations of the elements joined together with a copy of the specified delimiter.
    
    Parameters:
    
    delimiter - the delimiter that separates each element
    
    values - the values whose string representations to join together
    
    Returns:
    
    a new string that concatenates the string representations of the elements
  - joinLines
```
@SafeVarargs
public static <T> String joinLines(T... a)
```
    Concatenate the string representations of the objects, placing the system-specific line separator between them.
    
    Type Parameters:
    
    T - the type of array elements
    
    Parameters:
    
    a - array of values to concatenate
    
    Returns:
    
    the concatenation of the string representations of the values, each on its own line
  - joinLines
```
public static String joinLines(@Nullable Iterable<? extends Object> v)
```
    Concatenate the string representations of the objects, placing the system-specific line separator between them.
    
    Parameters:
    
    v - list of values to concatenate
    
    Returns:
    
    the concatenation of the string representations of the values, each on its own line
  - getBooleanSystemProperty
```
public static boolean getBooleanSystemProperty(String key)
```
    Return true if the system property is set to "true". Return false if the system property is not set or is set to "false". Otherwise, errs.
    
    Parameters:
    
    key - system property to check
    
    Returns:
    
    true if the system property is set to "true". Return false if the system property is not set or is set to "false". Otherwise, errs.
  - getBooleanSystemProperty
```
public static boolean getBooleanSystemProperty(String key,
                                               boolean defaultValue)
```
    Return its boolean value if the system property is set. Return defaultValue if the system property is not set. Errs if the system property is set to a non-boolean value.
    
    Parameters:
    
    key - system property to check
    
    defaultValue - value to use if the property is not set
    
    Returns:
    
    the boolean value of key or defaultValue if key is not set
  - getJreVersion
```
public static int getJreVersion()
```
    Returns the major JRE version.
    This is different from the version passed to the compiler via --release; use getReleaseValue(ProcessingEnvironment) to get that version.
    Extract the major version number from the "java.version" system property. Two possible formats are considered. Up to Java 8, from a version string like `1.8.whatever`, this method extracts 8. Since Java 9, from a version string like `11.0.1`, this method extracts 11.
    
    Returns:
    
    the major version number from "java.version"
  - getReleaseValue
```
public static @Nullable String getReleaseValue(ProcessingEnvironment env)
```
    Returns the release value passed to the compiler or null if release was not passed.
    
    Parameters:
    
    env - the ProcessingEnvironment
    
    Returns:
    
    the release value or null if none was passed
  - getToolsJar
```
public static @Nullable String getToolsJar()
```
    Returns the pathname to the tools.jar file, or null if it does not exist. Returns null on Java 9 and later.
    
    Returns:
    
    the pathname to the tools.jar file, or null
  - concatenate
```
public static <T> T[] concatenate(T[] array1,
                                  T... array2)
```
    Concatenates two arrays. Can be invoked varargs-style.
    
    Type Parameters:
    
    T - the type of the array elements
    
    Parameters:
    
    array1 - the first array
    
    array2 - the second array
    
    Returns:
    
    a new array containing the contents of the given arrays, in order
  - sleep
```
public static void sleep(long millis)
```
    Like Thread.sleep, but does not throw any exceptions, so it is easier for clients to use. Causes the currently executing thread to sleep (temporarily cease execution) for the specified number of milliseconds.
    
    Parameters:
    
    millis - the length of time to sleep in milliseconds

Class SystemUtil

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

SystemUtil

Method Detail

readFile

join

join

joinLines

joinLines

getBooleanSystemProperty

getBooleanSystemProperty

getJreVersion

getReleaseValue

getToolsJar

concatenate

sleep