com.levigo.jadice.server.util

Class Util

java.lang.Object

com.levigo.jadice.server.util.Util

public final class Util
extends Object

Useful utility methods.

Field Summary

Fields

Modifier and Type	Field and Description
static Class<?>[]	PRIMITIVE_TYPES Java's primitive types: Number String Boolean Character Date java.sql.Date Color URL URI

Method Summary

Methods

Modifier and Type	Method and Description
static <O> Iterable<O>	asIterable(Enumeration<O> enumeration) Wraps an Enumeration as a read-only Iterable so that it can be used in enhanced for-loops.
static long	copyAndClose(InputStream is, OutputStream os) Copies all data from input to output and closes the streams afterwards.
static long	copyStream(InputStream is, OutputStream os) Copies all data from input to output.
static boolean	deleteAllBelow(File dir) Recursively delete everything below a given directory, but don't remove the directory itself.
static boolean	deleteRecursively(Collection<File> files) Recursively delete several Files or directories.
static boolean	deleteRecursively(File file) Recursively delete a File or directory.
static long	discardStream(InputStream inputStream) Discards all data from a given InputStream but does not close it.
static String	fileToURL(File file) Create a correct file URL that LibreOffice can handle.
static <K,V> Map<V,K>	invertMap(Map<K,V> map) Inverts a Map from <K> → <V> to <V> → <K>.
static boolean	isPrimitivObject(Object obj, boolean considerCollections) Checks if a given object is an instance of a PRIMITIVE_TYPES or a Collection / Array / Map assembled of primitive types.
static String	join(Collection<String> values, String glue) Joins the given Strings as one single string, separated by the value glue.
static <K,V> void	put(Map<K,Set<V>> multimap, K key, V value) Utility method for putting values into a multimap.
static com.levigo.jadice.document.io.SeekableInputStream	wrapSeekable(InputStream is) Wraps a given InputStream into a seekable input stream (i.e.

Methods inherited from class java.lang.Object

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

Field Detail

PRIMITIVE_TYPES

public static final Class<?>[] PRIMITIVE_TYPES

Java's primitive types:

• Number
• String
• Boolean
• Character
• Date
• java.sql.Date
• Color
• URL
• URI

Method Detail

fileToURL

public static String fileToURL(File file)
                        throws IOException

Create a correct file URL that LibreOffice can handle. This is necessary to be platform independent.

Throws:

IOException

copyStream

public static long copyStream(InputStream is,
              OutputStream os)
                       throws IOException

Copies all data from input to output. Does not close the streams afterwards.

Parameters:

is - the source stream

os - the target stream

Returns:

number of bytes copied

Throws:

IOException

copyAndClose

public static long copyAndClose(InputStream is,
                OutputStream os)
                         throws IOException

Copies all data from input to output and closes the streams afterwards.

Parameters:

is - the source stream

os - the target stream

Returns:

number of bytes copied

Throws:

IOException

discardStream

public static long discardStream(InputStream inputStream)
                          throws IOException

Discards all data from a given InputStream but does not close it. This method can used as a /dev/null device.

Parameters:

inputStream - The stream to discard

Returns:

number of bytes discarded

Throws:

IOException - if an I/O error occurs.

wrapSeekable

public static com.levigo.jadice.document.io.SeekableInputStream wrapSeekable(InputStream is)
                                                                      throws IOException

Wraps a given InputStream into a seekable input stream (i.e. a MemoryInputStream) if it is not already seekable.

Parameters:

is - The stream to wrap

Returns:

the wrapped stream

Throws:

IOException

Since:

jadice server 5.4.2.0

deleteRecursively

public static boolean deleteRecursively(File file)

Recursively delete a File or directory.

Parameters:

file - The file or directory to delete

Returns:

true iff the file or directory and all of its content is successfully deleted

See Also:

File.delete()

deleteRecursively

public static boolean deleteRecursively(Collection<File> files)

Recursively delete several Files or directories.

Parameters:

files - The files or directories to delete

Returns:

true iff all files or directories and all of its contents are successfully deleted

See Also:

File.delete()

deleteAllBelow

public static boolean deleteAllBelow(File dir)

Recursively delete everything below a given directory, but don't remove the directory itself.

Parameters:

dir - The directory to delete

Returns:

true iff all of the directory's content is successfully deleted

See Also:

File.delete()

invertMap

public static <K,V> Map<V,K> invertMap(Map<K,V> map)

Inverts a Map from <K> → <V> to <V> → <K>. If the given map is not symmetric or contains null as key or value the result will differ from the expected result

Type Parameters:

K - former key type

V - former value type

Parameters:

map - the map to invert

Returns:

the inverted map

put

public static <K,V> void put(Map<K,Set<V>> multimap,
             K key,
             V value)

Utility method for putting values into a multimap.

Implementation note: If no entry is found so under the given key, a HashSet the will be created as the Set where the value is stored. So, the same value cannot be stored multiple times under a given key.

Type Parameters:

K - key type

V - value typ

Parameters:

multimap - where to store the value

key - key with which the specified value is to be associated.

value - value to be associated with the specified key.

isPrimitivObject

public static boolean isPrimitivObject(Object obj,
                       boolean considerCollections)

Checks if a given object is an instance of a PRIMITIVE_TYPES or a Collection / Array / Map assembled of primitive types.

Caveat: If considerCollections is true, empty collections will result with true as the generic type information is lost while the compilation.

Parameters:

obj - the object to check

considerCollections - if true Collections / Arrays / Maps are checked recursively

Returns:

true iff the given object is a primitive object (or assembled of them)

join

public static String join(Collection<String> values,
          String glue)

Joins the given Strings as one single string, separated by the value glue. This is the inverse operation to String.split(String).

Example: join({"a","b","c","d"}, ", ") ⇒ "a, b, c, d"

Parameters:

values - the String literals to join

glue - a value that is glued between the single literals, might also be empty or null

Returns:

the joined string

Since:

jadice server 4.3.1.0

See Also:

String.split(String)

asIterable

public static <O> Iterable<O> asIterable(Enumeration<O> enumeration)

Wraps an Enumeration as a read-only Iterable so that it can be used in enhanced for-loops. This wrapping is not thread-safe.

Type Parameters:

O - The enumeration's objects type

Parameters:

enumeration - the (old-fashioned) Enumeration

Returns:

A wrapping (new-fashioned) Iterable

Since:

jadice server 4.3.1.4