Tools (onlab-misc 1.3.0 API)

java.lang.Object
- org.onlab.util.Tools

public abstract class Tools
extends Object

Miscellaneous utility methods.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static byte[]`	`byteBuffertoArray(ByteBuffer buffer)` Returns the contents of `ByteBuffer` as byte array.
`static void`	`copyDirectory(File src, File dst)` Copies the specified directory path. Use with great caution since no attempt is made to check for symbolic links, which could result in copy of unintended files.
`static void`	`copyDirectory(String src, String dst)` Copies the specified directory path. Use with great caution since no attempt is made to check for symbolic links, which could result in copy of unintended files.
`static byte[]`	`copyOf(byte[] original)` Returns a copy of the input byte array.
`static void`	`delay(int ms)` Suspends the current thread for a specified number of millis.
`static void`	`delay(int ms, int nanos)` Suspends the current thread for a specified number of millis and nanos.
`static <T> CompletableFuture<T>`	`exceptionalFuture(Throwable t)` Returns a future that is completed exceptionally.
`static long`	`fromHex(String string)` Converts a string from hex to long.
`static <T> T`	`futureGetOrElse(Future<T> future, long timeout, TimeUnit timeUnit, T defaultValue)` Returns the future value when complete or if future completes exceptionally returns the defaultValue.
`static <T> T`	`futureGetOrElse(Future<T> future, T defaultValue)` Returns the future value when complete or if future completes exceptionally returns the defaultValue.
`static String`	`get(Dictionary<?,?> properties, String propertyName)` Get property as a string value.
`static ThreadFactory`	`groupedThreads(String groupName, String pattern)` Returns a thread factory that produces threads named according to the supplied name pattern and from the specified thread-group.
`static boolean`	`isNullOrEmpty(Collection collection)` Returns true if the collection is null or is empty.
`static ThreadFactory`	`minPriority(ThreadFactory factory)` Returns a thread factory that produces threads with MIN_PRIORITY.
`static ThreadFactory`	`namedThreads(String pattern)` Returns a thread factory that produces threads named according to the supplied name pattern.
`static <T> T`	`nullIsIllegal(T item, String message)` Returns the specified item if that item is not null; otherwise throws bad argument exception.
`static <T> T`	`nullIsNotFound(T item, String message)` Returns the specified item if that item is not null; otherwise throws not found exception.
`static void`	`randomDelay(int ms)` Suspends the current thread for a random number of millis between 0 and the indicated limit.
`static void`	`removeDirectory(File dir)` Purges the specified directory path. Use with great caution since no attempt is made to check for symbolic links, which could result in deletion of unintended files.
`static void`	`removeDirectory(String path)` Purges the specified directory path. Use with great caution since no attempt is made to check for symbolic links, which could result in deletion of unintended files.
`static <U,V> java.util.function.Function<U,V>`	`retryable(java.util.function.Function<U,V> base, Class<? extends Throwable> exceptionClass, int maxRetries, int maxDelayBetweenRetries)` Returns a function that retries execution on failure.
`static <V> java.util.function.Supplier<V>`	`retryable(java.util.function.Supplier<V> base, Class<? extends Throwable> exceptionClass, int maxRetries, int maxDelayBetweenRetries)` Returns a Supplier that retries execution on failure.
`static List<String>`	`slurp(File path)` Slurps the contents of a file into a list of strings, one per line.
`static <T> java.util.stream.Stream<T>`	`stream(Iterable<T> it)` Converts an iterable to a stream.
`static String`	`timeAgo(long unixTime)` Returns a human friendly time ago string for a specified system time.
`static String`	`toHex(long value)` Converts a long value to hex string; 16 wide and sans 0x.
`static String`	`toHex(long value, int width)` Converts a long value to hex string; 16 wide and sans 0x.

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

- Method Detail
  - namedThreads
```
public static ThreadFactory namedThreads(String pattern)
```
    Returns a thread factory that produces threads named according to the supplied name pattern.
    
    Parameters:
    
    pattern - name pattern
    
    Returns:
    
    thread factory
  - groupedThreads
```
public static ThreadFactory groupedThreads(String groupName,
                                           String pattern)
```
    Returns a thread factory that produces threads named according to the supplied name pattern and from the specified thread-group. The thread group name is expected to be specified in slash-delimited format, e.g. onos/intent. The thread names will be produced by converting the thread group name into dash-delimited format and pre-pended to the specified pattern.
    
    Parameters:
    
    groupName - group name in slash-delimited format to indicate hierarchy
    
    pattern - name pattern
    
    Returns:
    
    thread factory
  - minPriority
```
public static ThreadFactory minPriority(ThreadFactory factory)
```
    Returns a thread factory that produces threads with MIN_PRIORITY.
    
    Parameters:
    
    factory - backing ThreadFactory
    
    Returns:
    
    thread factory
  - isNullOrEmpty
```
public static boolean isNullOrEmpty(Collection collection)
```
    Returns true if the collection is null or is empty.
    
    Parameters:
    
    collection - collection to test
    
    Returns:
    
    true if null or empty; false otherwise
  - nullIsNotFound
```
public static <T> T nullIsNotFound(T item,
                                   String message)
```
    Returns the specified item if that item is not null; otherwise throws not found exception.
    
    Type Parameters:
    
    T - item type
    
    Parameters:
    
    item - item to check
    
    message - not found message
    
    Returns:
    
    item if not null
    
    Throws:
    
    ItemNotFoundException - if item is null
  - nullIsIllegal
```
public static <T> T nullIsIllegal(T item,
                                  String message)
```
    Returns the specified item if that item is not null; otherwise throws bad argument exception.
    
    Type Parameters:
    
    T - item type
    
    Parameters:
    
    item - item to check
    
    message - not found message
    
    Returns:
    
    item if not null
    
    Throws:
    
    IllegalArgumentException - if item is null
  - fromHex
```
public static long fromHex(String string)
```
    Converts a string from hex to long.
    
    Parameters:
    
    string - hex number in string form; sans 0x
    
    Returns:
    
    long value
  - toHex
```
public static String toHex(long value)
```
    Converts a long value to hex string; 16 wide and sans 0x.
    
    Parameters:
    
    value - long value
    
    Returns:
    
    hex string
  - toHex
```
public static String toHex(long value,
                           int width)
```
    Converts a long value to hex string; 16 wide and sans 0x.
    
    Parameters:
    
    value - long value
    
    width - string width; zero padded
    
    Returns:
    
    hex string
  - copyOf
```
public static byte[] copyOf(byte[] original)
```
    Returns a copy of the input byte array.
    
    Parameters:
    
    original - input
    
    Returns:
    
    copy of original
  - get
```
public static String get(Dictionary<?,?> properties,
                         String propertyName)
```
    Get property as a string value.
    
    Parameters:
    
    properties - properties to be looked up
    
    propertyName - the name of the property to look up
    
    Returns:
    
    value when the propertyName is defined or return null
  - delay
```
public static void delay(int ms)
```
    Suspends the current thread for a specified number of millis.
    
    Parameters:
    
    ms - number of millis
  - retryable
```
public static <U,V> java.util.function.Function<U,V> retryable(java.util.function.Function<U,V> base,
                                                               Class<? extends Throwable> exceptionClass,
                                                               int maxRetries,
                                                               int maxDelayBetweenRetries)
```
    Returns a function that retries execution on failure.
    
    Type Parameters:
    
    U - type of function input
    
    V - type of function output
    
    Parameters:
    
    base - base function
    
    exceptionClass - type of exception for which to retry
    
    maxRetries - max number of retries before giving up
    
    maxDelayBetweenRetries - max delay between successive retries. The actual delay is randomly picked from the interval (0, maxDelayBetweenRetries]
    
    Returns:
    
    function
  - retryable
```
public static <V> java.util.function.Supplier<V> retryable(java.util.function.Supplier<V> base,
                                                           Class<? extends Throwable> exceptionClass,
                                                           int maxRetries,
                                                           int maxDelayBetweenRetries)
```
    Returns a Supplier that retries execution on failure.
    
    Type Parameters:
    
    V - type of supplied result
    
    Parameters:
    
    base - base supplier
    
    exceptionClass - type of exception for which to retry
    
    maxRetries - max number of retries before giving up
    
    maxDelayBetweenRetries - max delay between successive retries. The actual delay is randomly picked from the interval (0, maxDelayBetweenRetries]
    
    Returns:
    
    supplier
  - randomDelay
```
public static void randomDelay(int ms)
```
    Suspends the current thread for a random number of millis between 0 and the indicated limit.
    
    Parameters:
    
    ms - max number of millis
  - delay
```
public static void delay(int ms,
                         int nanos)
```
    Suspends the current thread for a specified number of millis and nanos.
    
    Parameters:
    
    ms - number of millis
    
    nanos - number of nanos
  - slurp
```
public static List<String> slurp(File path)
```
    Slurps the contents of a file into a list of strings, one per line.
    
    Parameters:
    
    path - file path
    
    Returns:
    
    file contents
  - removeDirectory
```
public static void removeDirectory(String path)
                            throws IOException
```
    Purges the specified directory path. Use with great caution since no attempt is made to check for symbolic links, which could result in deletion of unintended files.
    
    Parameters:
    
    path - directory to be removed
    
    Throws:
    
    IOException - if unable to remove contents
  - removeDirectory
```
public static void removeDirectory(File dir)
                            throws IOException
```
    Purges the specified directory path. Use with great caution since no attempt is made to check for symbolic links, which could result in deletion of unintended files.
    
    Parameters:
    
    dir - directory to be removed
    
    Throws:
    
    IOException - if unable to remove contents
  - timeAgo
```
public static String timeAgo(long unixTime)
```
    Returns a human friendly time ago string for a specified system time.
    
    Parameters:
    
    unixTime - system time in millis
    
    Returns:
    
    human friendly time ago
  - copyDirectory
```
public static void copyDirectory(String src,
                                 String dst)
                          throws IOException
```
    Copies the specified directory path. Use with great caution since no attempt is made to check for symbolic links, which could result in copy of unintended files.
    
    Parameters:
    
    src - directory to be copied
    
    dst - destination directory to be removed
    
    Throws:
    
    IOException - if unable to remove contents
  - copyDirectory
```
public static void copyDirectory(File src,
                                 File dst)
                          throws IOException
```
    Copies the specified directory path. Use with great caution since no attempt is made to check for symbolic links, which could result in copy of unintended files.
    
    Parameters:
    
    src - directory to be copied
    
    dst - destination directory to be removed
    
    Throws:
    
    IOException - if unable to remove contents
  - futureGetOrElse
```
public static <T> T futureGetOrElse(Future<T> future,
                                    T defaultValue)
```
    Returns the future value when complete or if future completes exceptionally returns the defaultValue.
    
    Type Parameters:
    
    T - future value type
    
    Parameters:
    
    future - future
    
    defaultValue - default value
    
    Returns:
    
    future value when complete or if future completes exceptionally returns the defaultValue.
  - futureGetOrElse
```
public static <T> T futureGetOrElse(Future<T> future,
                                    long timeout,
                                    TimeUnit timeUnit,
                                    T defaultValue)
```
    Returns the future value when complete or if future completes exceptionally returns the defaultValue.
    
    Type Parameters:
    
    T - future value type
    
    Parameters:
    
    future - future
    
    timeout - time to wait for successful completion
    
    timeUnit - time unit
    
    defaultValue - default value
    
    Returns:
    
    future value when complete or if future completes exceptionally returns the defaultValue.
  - exceptionalFuture
```
public static <T> CompletableFuture<T> exceptionalFuture(Throwable t)
```
    Returns a future that is completed exceptionally.
    
    Type Parameters:
    
    T - future value type
    
    Parameters:
    
    t - exception
    
    Returns:
    
    future
  - byteBuffertoArray
```
public static byte[] byteBuffertoArray(ByteBuffer buffer)
```
    Returns the contents of ByteBuffer as byte array.
    WARNING: There is a performance cost due to array copy when using this method.
    
    Parameters:
    
    buffer - byte buffer
    
    Returns:
    
    byte array containing the byte buffer contents
  - stream
```
public static <T> java.util.stream.Stream<T> stream(Iterable<T> it)
```
    Converts an iterable to a stream.
    
    Type Parameters:
    
    T - type if item
    
    Parameters:
    
    it - iterable to convert
    
    Returns:
    
    iterable as a stream

Class Tools

Method Summary

Methods inherited from class java.lang.Object

Method Detail

namedThreads

groupedThreads

minPriority

isNullOrEmpty

nullIsNotFound

nullIsIllegal

fromHex

toHex

toHex

copyOf

get

delay

retryable

retryable

randomDelay

delay

slurp

removeDirectory

removeDirectory

timeAgo

copyDirectory

copyDirectory

futureGetOrElse

futureGetOrElse

exceptionalFuture

byteBuffertoArray

stream