gololang

Class Predefined

java.lang.Object

gololang.Predefined

public final class Predefined
extends java.lang.Object

Predefined provides the module of predefined functions in Golo. The provided module is imported by default.

Method Summary

Modifier and Type	Method and Description
static java.lang.Object[]	array(java.lang.Object... values) array constructor.
static java.lang.Class<?>	arrayTypeOf(java.lang.Object klass) Returns an array class given a type class.
static java.lang.Object	asFunctionalInterface(java.lang.Object type, java.lang.Object func) Turns a function reference into an instance of a Java 8 functional interface.
static java.lang.Object	asInterfaceInstance(java.lang.Object interfaceClass, java.lang.Object target) Turns a function reference into an instance of a single-method interface.
static java.math.BigDecimal	bigDecimalValue(java.lang.Object obj) Gives the BigDecimal value of some number or String object.
static java.math.BigInteger	bigIntegerValue(java.lang.Object obj) Gives the BigInteger value of some number or String object.
static java.lang.Object	box(java.lang.Object obj) Returns a box containing the given object.
static java.lang.Object	charValue(java.lang.Object obj) Gives the Character value of some number or String object.
static java.lang.String	currentDir() Return current path of execution.
static java.lang.Object	doubleValue(java.lang.Object obj) Gives the Double value of some number or String object.
static boolean	fileExists(java.lang.Object file) Check if a file exists.
static java.lang.Object	fileToText(java.lang.Object file, java.lang.Object encoding) Reads the content of a text file.
static java.lang.Object	floatValue(java.lang.Object obj) Gives the Float value of some number or String object.
static FunctionReference	fun(java.lang.Object name, java.lang.Object module) Obtains the first reference to a function.
static FunctionReference	fun(java.lang.Object name, java.lang.Object module, java.lang.Object arity) Obtains the first reference to a function.
static FunctionReference	fun(java.lang.Object name, java.lang.Object module, java.lang.Object arity, java.lang.Object varargs) Obtains a reference to a function.
static java.lang.Object	intValue(java.lang.Object obj) Gives the Integer value of some number or String object.
static boolean	isArray(java.lang.Object object) Checks if an object is a (JVM) array or not.
static boolean	isClosure(java.lang.Object object) Test whether an object is a closure or not.
static java.util.List<java.lang.Object>	list(java.lang.Object... values) Varargs version of a list constructor.
static java.lang.Object	longValue(java.lang.Object obj) Gives the Long value of some number or String object.
static java.util.Map<java.lang.Object,java.lang.Object>	map(Tuple... items) Varargs version of a map constructor.
static java.lang.Object	mapEntry(java.lang.Object key, java.lang.Object value) Makes a key / value pair.
static java.lang.Object	newTypedArray(java.lang.Class<?> type, int length) Makes a new typed JVM array.
static java.lang.Class<?>	objectArrayType() Function to obtain the Object[].class reference.
static void	print(java.lang.Object obj) Prints to the standard console.
static void	println(java.lang.Object obj) Prints to the standard console, including a newline.
static void	raise(java.lang.Object message) Raises a RuntimeException with a message.
static void	raise(java.lang.Object message, java.lang.Object cause) Raises a RuntimeException with a message and a cause.
static java.lang.Object	range(java.lang.Object to) Makes an range object starting from the default value.
static java.lang.Object	range(java.lang.Object from, java.lang.Object to) Makes an range object between two bounds.
static java.lang.String	readln() Reads the next line of characters from the console.
static java.lang.String	readln(java.lang.String message) Reads the next line of characters from the console.
static java.lang.String	readPassword() Reads a password from the console with echoing disabled.
static java.lang.String	readPassword(java.lang.String message) Reads a password from the console with echoing disabled.
static java.lang.Object	removeByIndex(java.util.List<?> lst, java.lang.Integer idx) Removes an element of a List by index.
static void	require(java.lang.Object condition, java.lang.Object errorMessage) Requires that a condition be true.
static void	requireNotNull(java.lang.Object obj) Requires that an object is not the null reference.
static java.lang.Object	reversedRange(java.lang.Object from) Makes an decreasing range object up to the default value.
static java.lang.Object	reversedRange(java.lang.Object from, java.lang.Object to) Makes an decreasing range object between two bounds.
static char[]	secureReadPassword() Reads a password from the console with echoing disabled, returning an char[] array.
static char[]	secureReadPassword(java.lang.String message) Reads a password from the console with echoing disabled, returning an char[] array.
static java.util.Set<java.lang.Object>	set(java.lang.Object... values) Varargs version of a set constructor.
static void	sleep(long ms) Sleep on the current thread.
static java.lang.String	str(java.lang.Object... args) Create a String by concatenating all arguments.
static void	textToFile(java.lang.Object text, java.lang.Object file) Writes some text to a file.
static void	textToFile(java.lang.Object text, java.lang.Object file, java.lang.Object charset) Writes some text to a file using the given Charset.
static Tuple	tuple(java.lang.Object... values) Tuple constructor.
static java.lang.String	uuid() Return a universally unique identifier as String.
static java.util.List<java.lang.Object>	vector(java.lang.Object... values) Varargs version of a vector constructor.

Methods inherited from class java.lang.Object

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

Method Detail

raise

public static void raise(java.lang.Object message)

Raises a RuntimeException with a message.

Parameters:

message - the exception description.

Throws:

java.lang.RuntimeException - (always)

raise

public static void raise(java.lang.Object message,
                         java.lang.Object cause)

Raises a RuntimeException with a message and a cause.

Parameters:

message - the exception description.

cause - the exception cause.

Throws:

java.lang.RuntimeException - (always)

print

public static void print(java.lang.Object obj)

Prints to the standard console.

Parameters:

obj - the object to be printed.

println

public static void println(java.lang.Object obj)

Prints to the standard console, including a newline.

Parameters:

obj - obj the object to be printed.

readln

public static java.lang.String readln()
                               throws java.io.IOException

Reads the next line of characters from the console.

Returns:

a String.

Throws:

java.io.IOException

readln

public static java.lang.String readln(java.lang.String message)
                               throws java.io.IOException

Reads the next line of characters from the console.

Parameters:

message - displays a prompt message.

Returns:

a String.

Throws:

java.io.IOException

readPassword

public static java.lang.String readPassword()
                                     throws java.io.IOException

Reads a password from the console with echoing disabled.

Returns:

a String.

Throws:

java.io.IOException

readPassword

public static java.lang.String readPassword(java.lang.String message)
                                     throws java.io.IOException

Reads a password from the console with echoing disabled.

Parameters:

message - displays a prompt message.

Returns:

a String.

Throws:

java.io.IOException

secureReadPassword

public static char[] secureReadPassword()
                                 throws java.io.IOException

Reads a password from the console with echoing disabled, returning an char[] array.

Returns:

a character array.

Throws:

java.io.IOException

secureReadPassword

public static char[] secureReadPassword(java.lang.String message)
                                 throws java.io.IOException

Reads a password from the console with echoing disabled, returning an char[] array.

Parameters:

message - displays a prompt message.

Returns:

a character array.

Throws:

java.io.IOException

requireNotNull

public static void requireNotNull(java.lang.Object obj)
                           throws java.lang.AssertionError

Requires that an object is not the null reference.

Parameters:

obj - the object to test against null.

Throws:

java.lang.AssertionError - if obj is null.

require

public static void require(java.lang.Object condition,
                           java.lang.Object errorMessage)
                    throws java.lang.IllegalArgumentException,
                           java.lang.AssertionError

Requires that a condition be true.

Parameters:

condition - the condition, must be a Boolean.

errorMessage - the error message, must be a String.

Throws:

java.lang.IllegalArgumentException - if the arguments are of the wrong type.

java.lang.AssertionError - if condition is false.

newTypedArray

public static java.lang.Object newTypedArray(java.lang.Class<?> type,
                                             int length)

Makes a new typed JVM array. This function simply forwards to java.lang.reflect.Array.newInstance.

Parameters:

type - the array type.

length - the array length.

Returns:

a new typed array.

range

public static java.lang.Object range(java.lang.Object from,
                                     java.lang.Object to)

Makes an range object between two bounds. Range objects implement java.lang.Collection (immutable), so they can be used in Golo foreach loops.

Parameters:

from - the lower-bound (inclusive) as an Integer, Long, Character or BigInteger.

to - the upper-bound (exclusive) as an Integer, Long, Character or BigInteger.

Returns:

a range object.

See Also:

Collection

range

public static java.lang.Object range(java.lang.Object to)

Makes an range object starting from the default value.

The default value is 0 for numbers and 'A' for chars.

Parameters:

to - the upper-bound (exclusive) as an Integer, Long, Character or BigInteger.

Returns:

a range object.

See Also:

range(java.lang.Object, java.lang.Object)

reversedRange

public static java.lang.Object reversedRange(java.lang.Object from,
                                             java.lang.Object to)

Makes an decreasing range object between two bounds. Range objects implement java.lang.Collection, so they can be used in Golo foreach loops.

Parameters:

from - the upper-bound (inclusive) as an Integer, Long, Character or BigInteger.

to - the lower-bound (exclusive) as an Integer, Long, Character or BigInteger.

Returns:

a range object.

See Also:

range(java.lang.Object, java.lang.Object)

reversedRange

public static java.lang.Object reversedRange(java.lang.Object from)

Makes an decreasing range object up to the default value.

The default value is 0 for numbers and 'A' for chars.

Parameters:

from - the upper-bound (inclusive) as an Integer, Long, Character or BigInteger.

Returns:

a range object.

See Also:

reversedRange(java.lang.Object, java.lang.Object), range(java.lang.Object, java.lang.Object)

mapEntry

public static java.lang.Object mapEntry(java.lang.Object key,
                                        java.lang.Object value)

Makes a key / value pair.

Parameters:

key - the key.

value - the value.

Returns:

an instance of AbstractMap.SimpleEntry

See Also:

AbstractMap.SimpleEntry

asInterfaceInstance

public static java.lang.Object asInterfaceInstance(java.lang.Object interfaceClass,
                                                   java.lang.Object target)

Turns a function reference into an instance of a single-method interface.

Parameters:

interfaceClass - the target single-method interface class.

target - the implementation function reference.

Returns:

an instance of interfaceClass.

See Also:

MethodHandleProxies.asInterfaceInstance(Class, java.lang.invoke.MethodHandle)

asFunctionalInterface

public static java.lang.Object asFunctionalInterface(java.lang.Object type,
                                                     java.lang.Object func)
                                              throws java.lang.Throwable

Turns a function reference into an instance of a Java 8 functional interface. The implementation delegates to Golo adapter fabrics.

Parameters:

type - the functional interface class.

func - the implementation function.

Returns:

an instance of type.

Throws:

java.lang.Throwable - if the adaptation fails.

See Also:

GoloAdapter

isClosure

public static boolean isClosure(java.lang.Object object)

Test whether an object is a closure or not.

Parameters:

object - the object.

Returns:

true if object is an instance of FunctionReference false otherwise.

fun

public static FunctionReference fun(java.lang.Object name,
                                    java.lang.Object module,
                                    java.lang.Object arity,
                                    java.lang.Object varargs)
                             throws java.lang.Throwable

Obtains a reference to a function.

Parameters:

name - the function name.

module - the function enclosing module (a Java class).

arity - the function arity, where a negative value means that any arity will do.

varargs - if the functions has variable arity.

Returns:

a function reference to the matched function.

Throws:

java.lang.NoSuchMethodException - if the target function could not be found.

java.lang.IllegalArgumentException - if the argument types are not of types (String, Class, Integer).

java.lang.Throwable - if an error occurs.

fun

public static FunctionReference fun(java.lang.Object name,
                                    java.lang.Object module,
                                    java.lang.Object arity)
                             throws java.lang.Throwable

Obtains the first reference to a function.

This is the same as calling fun(name, module, arity, false).

Throws:

java.lang.Throwable

See Also:

fun(Object, Object, Object, Object)

fun

public static FunctionReference fun(java.lang.Object name,
                                    java.lang.Object module)
                             throws java.lang.Throwable

Obtains the first reference to a function.

This is the same as calling fun(name, module, -1).

Throws:

java.lang.Throwable

See Also:

fun(Object, Object, Object)

fileToText

public static java.lang.Object fileToText(java.lang.Object file,
                                          java.lang.Object encoding)
                                   throws java.lang.Throwable

Reads the content of a text file.

Parameters:

file - the file to read from as an instance of either String, File or Path.

encoding - the file encoding as a String or Charset.

Returns:

the content as a String.

Throws:

java.lang.Throwable

textToFile

public static void textToFile(java.lang.Object text,
                              java.lang.Object file)
                       throws java.lang.Throwable

Writes some text to a file. The file and parents directories are created if they does not exist. The file is overwritten if it already exists. If the file is "-", the content is written to standard output.

Parameters:

text - the text to write.

file - the file to write to as an instance of either String, File or Path.

Throws:

java.lang.Throwable

textToFile

public static void textToFile(java.lang.Object text,
                              java.lang.Object file,
                              java.lang.Object charset)
                       throws java.lang.Throwable

Writes some text to a file using the given Charset. The file and parents directories are created if they does not exist. The file is overwritten if it already exists. If the file is "-", the content is written to standard output.

Parameters:

text - the text to write.

file - the file to write to as an instance of either String, File or Path.

charset - the charset to encode the text in.

Throws:

java.lang.Throwable

fileExists

public static boolean fileExists(java.lang.Object file)

Check if a file exists.

Parameters:

file - the file to read from as an instance of either String, File or Path.

Returns:

true if the file exists, false if it doesn't

currentDir

public static java.lang.String currentDir()
                                   throws java.lang.Throwable

Return current path of execution.

Returns:

current path of execution

Throws:

java.lang.Throwable

sleep

public static void sleep(long ms)
                  throws java.lang.InterruptedException

Sleep on the current thread.

Parameters:

ms - time in milliseconds.

Throws:

java.lang.InterruptedException - in case the thread gets interrupted.

uuid

public static java.lang.String uuid()

Return a universally unique identifier as String.

Returns:

a universally unique identifier as String

isArray

public static boolean isArray(java.lang.Object object)

Checks if an object is a (JVM) array or not.

Parameters:

object - the object to check.

Returns:

true if object is an array, false otherwise or if null.

objectArrayType

public static java.lang.Class<?> objectArrayType()

Function to obtain the Object[].class reference.

Returns:

Object[].class

arrayTypeOf

public static java.lang.Class<?> arrayTypeOf(java.lang.Object klass)
                                      throws java.lang.ClassNotFoundException

Returns an array class given a type class.

Parameters:

klass - the array type.

Returns:

the class of the array of type klass, i.e., klass[].

Throws:

java.lang.ClassNotFoundException - if the type could not be found.

charValue

public static java.lang.Object charValue(java.lang.Object obj)
                                  throws java.lang.IllegalArgumentException

Gives the Character value of some number or String object.

Parameters:

obj - a boxed number or String value.

Returns:

the Character value.

Throws:

java.lang.IllegalArgumentException - if obj is not a number or a String.

intValue

public static java.lang.Object intValue(java.lang.Object obj)
                                 throws java.lang.IllegalArgumentException

Gives the Integer value of some number or String object.

Parameters:

obj - a boxed number or String value.

Returns:

the Integer value.

Throws:

java.lang.IllegalArgumentException - if obj is not a number or a String.

longValue

public static java.lang.Object longValue(java.lang.Object obj)
                                  throws java.lang.IllegalArgumentException

Gives the Long value of some number or String object.

Parameters:

obj - a boxed number or String value.

Returns:

the Long value.

Throws:

java.lang.IllegalArgumentException - if obj is not a number or a String.

doubleValue

public static java.lang.Object doubleValue(java.lang.Object obj)
                                    throws java.lang.IllegalArgumentException

Gives the Double value of some number or String object.

Parameters:

obj - a boxed number or String value.

Returns:

the Double value.

Throws:

java.lang.IllegalArgumentException - if obj is not a number or a String.

floatValue

public static java.lang.Object floatValue(java.lang.Object obj)
                                   throws java.lang.IllegalArgumentException

Gives the Float value of some number or String object.

Parameters:

obj - a boxed number or String value.

Returns:

the Float value.

Throws:

java.lang.IllegalArgumentException - if obj is not a number or a String.

bigDecimalValue

public static java.math.BigDecimal bigDecimalValue(java.lang.Object obj)
                                            throws java.lang.IllegalArgumentException

Gives the BigDecimal value of some number or String object.

Parameters:

obj - a boxed number or String value.

Returns:

the Float value.

Throws:

java.lang.IllegalArgumentException - if obj is not a number or a String.

bigIntegerValue

public static java.math.BigInteger bigIntegerValue(java.lang.Object obj)
                                            throws java.lang.IllegalArgumentException

Gives the BigInteger value of some number or String object.

Parameters:

obj - a boxed number or String value.

Returns:

the Float value.

Throws:

java.lang.IllegalArgumentException - if obj is not a number or a String.

str

public static java.lang.String str(java.lang.Object... args)

Create a String by concatenating all arguments.

For instance:

 let s = str("The answer", " is ", 2 * 21)
 

This is functionally equivalent to:

 let s = ["The answer", " is ", 2 * 21]: join("")
 

removeByIndex

public static java.lang.Object removeByIndex(java.util.List<?> lst,
                                             java.lang.Integer idx)

Removes an element of a List by index.

Parameters:

lst - the list to remove the element from.

idx - an Integer representing the index of the element to remove.

Returns:

the element that was removed.

Throws:

java.lang.IndexOutOfBoundsException - if idx

box

public static java.lang.Object box(java.lang.Object obj)

Returns a box containing the given object.

Useful whenever an explicit reference is needed, for instance to create a closure with internal mutable state:

    function counter = |init| {
      let current = box(init)
      return -> current: getAndSet(current: get() + 1)
    }

    let c = counter(3)
    c() # 3
    c() # 4
    c() # 5
 

Parameters:

obj - the object to reference.

Returns:

a java.util.concurrent.atomic.AtomicReference instance wrapping the object

list

public static java.util.List<java.lang.Object> list(java.lang.Object... values)

Varargs version of a list constructor.

Returns:

a list of the given values.

set

public static java.util.Set<java.lang.Object> set(java.lang.Object... values)

Varargs version of a set constructor.

Returns:

a set of the given values.

array

public static java.lang.Object[] array(java.lang.Object... values)

array constructor.

Returns:

an array of the given values.

vector

public static java.util.List<java.lang.Object> vector(java.lang.Object... values)

Varargs version of a vector constructor.

Returns:

a vector of the give values.

tuple

public static Tuple tuple(java.lang.Object... values)

Tuple constructor.

Returns:

a tuple of the given values.

map

public static java.util.Map<java.lang.Object,java.lang.Object> map(Tuple... items)

Varargs version of a map constructor.

Parameters:

items - tuples containing the key and the value.

Returns:

a map corresponding to the given key/value pairs.