Utils (JOSM)

java.lang.Object
- org.openstreetmap.josm.tools.Utils

```
public final class Utils
extends Object
```
Basic utils, that can be useful in different parts of the program.

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static interface Utils.Function<A,B>
Represents a function that can be applied to objects of A and returns objects of B.

Nested Classes
Modifier and Type	Class and Description
`static interface`	`Utils.Function<A,B>` Represents a function that can be applied to objects of `A` and returns objects of `B`.

Field Summary

Fields
Modifier and Type Field and Description

private static double EPSILON

private static char[] HEX_ARRAY

Fields
Modifier and Type	Field and Description
`private static double`	`EPSILON`
`private static char[]`	`HEX_ARRAY`

Constructor Summary

Constructors
Modifier Constructor and Description

private Utils()

Constructors
Modifier	Constructor and Description
`private`	`Utils()`

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static void`	`close(Closeable c)` Utility method for closing a `Closeable` object.
`static void`	`close(ZipFile zip)` Utility method for closing a `ZipFile`.
`static Integer`	`color_float2int(Float val)` convert float range 0 <= x <= 1 to integer range 0..255 when dealing with colors and color alpha value
`static Float`	`color_int2float(Integer val)` convert back
`static Color`	`complement(Color clr)`
`static char[]`	`copyArray(char[] array)` Copies the given array.
`static <T> T[]`	`copyArray(T[] array)` Copies the given array.
`static void`	`copyFile(File in, File out)` Simple file copy function that will overwrite the target file.
`static int`	`copyStream(InputStream source, OutputStream destination)`
`static boolean`	`copyToClipboard(String s)` Copies the string `s` to system clipboard.
`static boolean`	`deleteDirectory(File path)`
`static void`	`ensure(boolean condition, String message, Object... data)`
`static <T> boolean`	`equal(T a, T b)` for convenience: test whether 2 objects are either both null or a.equals(b)
`static boolean`	`equalsEpsilon(double a, double b)` Determines if the two given double values are equal (their delta being smaller than a fixed epsilon)
`static String`	`execOutput(List<String> command)` Runs an external command and returns the standard output.
`static <T> boolean`	`exists(Iterable<? extends T> collection, Predicate<? super T> predicate)`
`static <T> boolean`	`exists(Iterable<T> collection, Class<? extends T> klass)`
`static <T> Collection<T>`	`filter(Collection<? extends T> collection, Predicate<? super T> predicate)`
`static <S,T extends S> SubclassFilteredCollection<S,T>`	`filteredCollection(Collection<S> collection, Class<T> klass)` Filter a collection by (sub)class.
`static <T> T`	`find(Iterable<? extends T> collection, Predicate<? super T> predicate)`
`static <T> T`	`find(Iterable<? super T> collection, Class<? extends T> klass)`
`static <T> T`	`firstNonNull(T... items)`
`static String`	`getClipboardContent()` Extracts clipboard content as string.
`static String`	`getDurationString(long elapsedTime)` Returns a simple human readable (hours, minutes, seconds) string for a given duration in milliseconds.
`static File`	`getJosmTempDir()` Returns the JOSM temp directory.
`static Color`	`hexToColor(String s)` Convert Hex String to Color.
`static <T> int`	`indexOf(Iterable<? extends T> collection, Predicate<? super T> predicate)`
`static String`	`join(String sep, Collection<?> values)` Joins a list of strings (or objects that can be converted to string via Object.toString()) into a single string with fields separated by sep.
`static String`	`joinAsHtmlUnorderedList(Collection<?> values)`
`static int`	`max(int a, int b, int c, int d)`
`static String`	`md5Hex(String data)` Calculate MD5 hash of a string and output in hexadecimal format.
`static int`	`min(int a, int b, int c)` Get minimum of 3 values
`static int`	`mod(int a, int n)` return the modulus in the range [0, n)
`static HttpURLConnection`	`openHttpConnection(URL httpURL)` Opens a HTTP connection to the given URL and sets the User-Agent property to JOSM's one.
`static HttpURLConnection`	`openHttpConnection(URL httpURL, boolean keepAlive)` Opens a HTTP connection to the given URL, sets the User-Agent property to JOSM's one and optionnaly disables Keep-Alive.
`static InputStream`	`openURL(URL url)` Opens a connection to the given URL and sets the User-Agent property to JOSM's one.
`static InputStream`	`openURLAndDecompress(URL url, boolean decompress)` Opens a connection to the given URL, sets the User-Agent property to JOSM's one, and decompresses stream if necessary.
`static BufferedReader`	`openURLReader(URL url)` Opens a connection to the given URL and sets the User-Agent property to JOSM's one.
`static BufferedReader`	`openURLReaderAndDecompress(URL url, boolean decompress)` Opens a connection to the given URL and sets the User-Agent property to JOSM's one.
`static URLConnection`	`setupURLConnection(URLConnection connection)` Setups the given URL connection to match JOSM needs by setting its User-Agent and timeout properties.
`static String`	`strip(String str)` An alternative to `String.trim()` to effectively remove all leading and trailing white characters, including Unicode ones.
`static String`	`toHexString(byte[] bytes)` Converts a byte array to a string of hexadecimal characters.
`static <T> List<T>`	`topologicalSort(MultiMap<T,T> dependencies)` Topological sort.
`static String`	`toString(Color c)` convert Color to String (Color.toString() omits alpha value)
`static <A,B> Collection<B>`	`transform(Collection<? extends A> c, Utils.Function<A,B> f)` Transforms the collection `c` into an unmodifiable collection and applies the `Utils.Function` `f` on each element upon access.
`static <A,B> List<B>`	`transform(List<? extends A> l, Utils.Function<A,B> f)` Transforms the list `l` into an unmodifiable list and applies the `Utils.Function` `f` on each element upon access.

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

- Field Detail
  - EPSILON
```
private static final double EPSILON
```
    See Also:
    
    Constant Field Values
  - HEX_ARRAY
```
private static final char[] HEX_ARRAY
```
- Constructor Detail
  - Utils
```
private Utils()
```
- Method Detail
  - exists
```
public static <T> boolean exists(Iterable<? extends T> collection,
                                 Predicate<? super T> predicate)
```
  - exists
```
public static <T> boolean exists(Iterable<T> collection,
                                 Class<? extends T> klass)
```
  - find
```
public static <T> T find(Iterable<? extends T> collection,
                         Predicate<? super T> predicate)
```
  - find
```
public static <T> T find(Iterable<? super T> collection,
                         Class<? extends T> klass)
```
  - filter
```
public static <T> Collection<T> filter(Collection<? extends T> collection,
                                       Predicate<? super T> predicate)
```
  - firstNonNull
```
public static <T> T firstNonNull(T... items)
```
  - filteredCollection
```
public static <S,T extends S> SubclassFilteredCollection<S,T> filteredCollection(Collection<S> collection,
                                                                                 Class<T> klass)
```
    Filter a collection by (sub)class. This is an efficient read-only implementation.
  - indexOf
```
public static <T> int indexOf(Iterable<? extends T> collection,
                              Predicate<? super T> predicate)
```
  - min
```
public static int min(int a,
                      int b,
                      int c)
```
    Get minimum of 3 values
  - max
```
public static int max(int a,
                      int b,
                      int c,
                      int d)
```
  - equal
```
public static <T> boolean equal(T a,
                                T b)
```
    for convenience: test whether 2 objects are either both null or a.equals(b)
  - ensure
```
public static void ensure(boolean condition,
                          String message,
                          Object... data)
```
  - mod
```
public static int mod(int a,
                      int n)
```
    return the modulus in the range [0, n)
  - join
```
public static String join(String sep,
                          Collection<?> values)
```
    Joins a list of strings (or objects that can be converted to string via Object.toString()) into a single string with fields separated by sep.
    
    Parameters:
    
    sep - the separator
    
    values - collection of objects, null is converted to the empty string
    
    Returns:
    
    null if values is null. The joined string otherwise.
  - joinAsHtmlUnorderedList
```
public static String joinAsHtmlUnorderedList(Collection<?> values)
```
  - toString
```
public static String toString(Color c)
```
    convert Color to String (Color.toString() omits alpha value)
  - color_float2int
```
public static Integer color_float2int(Float val)
```
    convert float range 0 <= x <= 1 to integer range 0..255 when dealing with colors and color alpha value
    
    Returns:
    
    null if val is null, the corresponding int if val is in the range 0...1. If val is outside that range, return 255
  - color_int2float
```
public static Float color_int2float(Integer val)
```
    convert back
  - complement
```
public static Color complement(Color clr)
```
  - copyArray
```
public static <T> T[] copyArray(T[] array)
```
    Copies the given array. Unlike Arrays.copyOf(T[], int), this method is null-safe.
    
    Parameters:
    
    array - The array to copy
    
    Returns:
    
    A copy of the original array, or null if array is null
    
    Since:
    
    6221
  - copyArray
```
public static char[] copyArray(char[] array)
```
    Copies the given array. Unlike Arrays.copyOf(T[], int), this method is null-safe.
    
    Parameters:
    
    array - The array to copy
    
    Returns:
    
    A copy of the original array, or null if array is null
    
    Since:
    
    6222
  - copyFile
```
public static void copyFile(File in,
                            File out)
                     throws IOException
```
    Simple file copy function that will overwrite the target file.
    Taken from this article (CC-NC-BY-SA)
    
    Parameters:
    
    in - The source file
    
    out - The destination file
    
    Throws:
    
    IOException - If any I/O error occurs
  - copyStream
```
public static int copyStream(InputStream source,
                             OutputStream destination)
                      throws IOException
```
    Throws:
    
    IOException
  - deleteDirectory
```
public static boolean deleteDirectory(File path)
```
  - close
```
public static void close(Closeable c)
```
    Utility method for closing a Closeable object.
    
    Parameters:
    
    c - the closeable object. May be null.
  - close
```
public static void close(ZipFile zip)
```
    Utility method for closing a ZipFile.
    
    Parameters:
    
    zip - the zip file. May be null.
  - equalsEpsilon
```
public static boolean equalsEpsilon(double a,
                                    double b)
```
    Determines if the two given double values are equal (their delta being smaller than a fixed epsilon)
    
    Parameters:
    
    a - The first double value to compare
    
    b - The second double value to compare
    
    Returns:
    
    true if abs(a - b) <= 1e-11, false otherwise
  - copyToClipboard
```
public static boolean copyToClipboard(String s)
```
    Copies the string s to system clipboard.
    
    Parameters:
    
    s - string to be copied to clipboard.
    
    Returns:
    
    true if succeeded, false otherwise.
  - getClipboardContent
```
public static String getClipboardContent()
```
    Extracts clipboard content as string.
    
    Returns:
    
    string clipboard contents if available, null otherwise.
  - md5Hex
```
public static String md5Hex(String data)
```
    Calculate MD5 hash of a string and output in hexadecimal format.
    
    Parameters:
    
    data - arbitrary String
    
    Returns:
    
    MD5 hash of data, string of length 32 with characters in range [0-9a-f]
  - toHexString
```
public static String toHexString(byte[] bytes)
```
    Converts a byte array to a string of hexadecimal characters. Preserves leading zeros, so the size of the output string is always twice the number of input bytes.
    
    Parameters:
    
    bytes - the byte array
    
    Returns:
    
    hexadecimal representation
  - topologicalSort
```
public static <T> List<T> topologicalSort(MultiMap<T,T> dependencies)
```
    Topological sort.
    
    Parameters:
    
    dependencies - contains mappings (key -> value). In the final list of sorted objects, the key will come after the value. (In other words, the key depends on the value(s).) There must not be cyclic dependencies.
    
    Returns:
    
    the list of sorted objects
  - transform
```
public static <A,B> Collection<B> transform(Collection<? extends A> c,
                                            Utils.Function<A,B> f)
```
    Transforms the collection c into an unmodifiable collection and applies the Utils.Function f on each element upon access.
    
    Type Parameters:
    
    A - class of input collection
    
    B - class of transformed collection
    
    Parameters:
    
    c - a collection
    
    f - a function that transforms objects of A to objects of B
    
    Returns:
    
    the transformed unmodifiable collection
  - transform
```
public static <A,B> List<B> transform(List<? extends A> l,
                                      Utils.Function<A,B> f)
```
    Transforms the list l into an unmodifiable list and applies the Utils.Function f on each element upon access.
    
    Type Parameters:
    
    A - class of input collection
    
    B - class of transformed collection
    
    Parameters:
    
    l - a collection
    
    f - a function that transforms objects of A to objects of B
    
    Returns:
    
    the transformed unmodifiable list
  - hexToColor
```
public static Color hexToColor(String s)
```
    Convert Hex String to Color.
    
    Parameters:
    
    s - Must be of the form "#34a300" or "#3f2", otherwise throws Exception. Upper/lower case does not matter.
    
    Returns:
    
    The corresponding color.
  - openHttpConnection
```
public static HttpURLConnection openHttpConnection(URL httpURL)
                                            throws IOException
```
    Opens a HTTP connection to the given URL and sets the User-Agent property to JOSM's one.
    
    Parameters:
    
    httpURL - The HTTP url to open (must use http:// or https://)
    
    Returns:
    
    An open HTTP connection to the given URL
    
    Throws:
    
    IOException - if an I/O exception occurs.
    
    Since:
    
    5587
  - openURL
```
public static InputStream openURL(URL url)
                           throws IOException
```
    Opens a connection to the given URL and sets the User-Agent property to JOSM's one.
    
    Parameters:
    
    url - The url to open
    
    Returns:
    
    An stream for the given URL
    
    Throws:
    
    IOException - if an I/O exception occurs.
    
    Since:
    
    5867
  - openURLAndDecompress
```
public static InputStream openURLAndDecompress(URL url,
                                               boolean decompress)
                                        throws IOException
```
    Opens a connection to the given URL, sets the User-Agent property to JOSM's one, and decompresses stream if necessary.
    
    Parameters:
    
    url - The url to open
    
    decompress - whether to wrap steam in a GZIPInputStream or CBZip2InputStream if the Content-Type header is set accordingly.
    
    Returns:
    
    An stream for the given URL
    
    Throws:
    
    IOException - if an I/O exception occurs.
    
    Since:
    
    6421
  - setupURLConnection
```
public static URLConnection setupURLConnection(URLConnection connection)
```
    Setups the given URL connection to match JOSM needs by setting its User-Agent and timeout properties.
    
    Parameters:
    
    connection - The connection to setup
    
    Returns:
    
    connection, with updated properties
    
    Since:
    
    5887
  - openURLReader
```
public static BufferedReader openURLReader(URL url)
                                    throws IOException
```
    Opens a connection to the given URL and sets the User-Agent property to JOSM's one.
    
    Parameters:
    
    url - The url to open
    
    Returns:
    
    An buffered stream reader for the given URL (using UTF-8)
    
    Throws:
    
    IOException - if an I/O exception occurs.
    
    Since:
    
    5868
  - openURLReaderAndDecompress
```
public static BufferedReader openURLReaderAndDecompress(URL url,
                                                        boolean decompress)
                                                 throws IOException
```
    Opens a connection to the given URL and sets the User-Agent property to JOSM's one.
    
    Parameters:
    
    url - The url to open
    
    decompress - whether to wrap steam in a GZIPInputStream or CBZip2InputStream if the Content-Type header is set accordingly.
    
    Returns:
    
    An buffered stream reader for the given URL (using UTF-8)
    
    Throws:
    
    IOException - if an I/O exception occurs.
    
    Since:
    
    6421
  - openHttpConnection
```
public static HttpURLConnection openHttpConnection(URL httpURL,
                                                   boolean keepAlive)
                                            throws IOException
```
    Opens a HTTP connection to the given URL, sets the User-Agent property to JOSM's one and optionnaly disables Keep-Alive.
    
    Parameters:
    
    httpURL - The HTTP url to open (must use http:// or https://)
    
    keepAlive - whether not to set header Connection=close
    
    Returns:
    
    An open HTTP connection to the given URL
    
    Throws:
    
    IOException - if an I/O exception occurs.
    
    Since:
    
    5587
  - strip
```
public static String strip(String str)
```
    An alternative to String.trim() to effectively remove all leading and trailing white characters, including Unicode ones.
    
    Parameters:
    
    str - The string to strip
    
    Returns:
    
    str, without leading and trailing characters, according to Character.isWhitespace(char) and Character.isSpaceChar(char).
    
    Since:
    
    5772
    
    See Also:
    
    Java’s String.trim has a strange idea of whitespace, JDK bug 4080617
  - execOutput
```
public static String execOutput(List<String> command)
                         throws IOException
```
    Runs an external command and returns the standard output. The program is expected to execute fast.
    
    Parameters:
    
    command - the command with arguments
    
    Returns:
    
    the output
    
    Throws:
    
    IOException - when there was an error, e.g. command does not exist
  - getJosmTempDir
```
public static File getJosmTempDir()
```
    Returns the JOSM temp directory.
    
    Returns:
    
    The JOSM temp directory (<java.io.tmpdir>/JOSM), or null if java.io.tmpdir is not defined
    
    Since:
    
    6245
  - getDurationString
```
public static String getDurationString(long elapsedTime)
                                throws IllegalArgumentException
```
    Returns a simple human readable (hours, minutes, seconds) string for a given duration in milliseconds.
    
    Parameters:
    
    elapsedTime - The duration in milliseconds
    
    Returns:
    
    A human redable string for the given duration
    
    Throws:
    
    IllegalArgumentException - if elapsedTime is < 0
    
    Since:
    
    6354

Class Utils

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

EPSILON

HEX_ARRAY

Constructor Detail

Utils

Method Detail

exists

exists

find

find

filter

firstNonNull

filteredCollection

indexOf

min

max

equal

ensure

mod

join

joinAsHtmlUnorderedList

toString

color_float2int

color_int2float

complement

copyArray

copyArray

copyFile

copyStream

deleteDirectory

close

close

equalsEpsilon

copyToClipboard

getClipboardContent

md5Hex

toHexString

topologicalSort

transform

transform

hexToColor

openHttpConnection

openURL

openURLAndDecompress

setupURLConnection

openURLReader

openURLReaderAndDecompress

openHttpConnection

strip

execOutput

getJosmTempDir

getDurationString