Types (j(s)-lib Commons 1.1.3 API)

java.lang.Object
- js.util.Types

public class Types
extends Object

Duck typing predicates. This utility class supplies predicates for type discovery at runtime; it is inspired by JavaScript paradigm. Although uncommon for utility classes this one allows for sub-classing, see sample code.

 class Types extends js.util.Types {
        public static boolean isWunderObject(Object o) {
                return o instanceof WunderObject;
        }
 }
 ...
 if(Types.isInstanceOf(object, StandardObject.class)) { // predicate provided by base class
        ...
 }
 if(Types.isWunderObject(object)) { // predicate provided by extension
        ...             
 }

Version:: final
Author:: Iulian Rotaru

Field Summary

Fields
Modifier and Type	Field and Description
`private static Map<Type,Type>`	`BOXING_MAP` Java language primitive values boxing classes.
`private static Pattern`	`CLASS_NAME_PATTERN` Pattern constant used for Java class name validation.
`private static Type[]`	`NUMERICAL_TYPES` Java standard classes used to represent numbers, including primitives.

Constructor Summary

Constructors
Modifier Constructor and Description

protected Types()
Prevent default constructor synthesis but allow sub-classing.

Constructors
Modifier	Constructor and Description
`protected`	`Types()` Prevent default constructor synthesis but allow sub-classing.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static boolean`	`asBoolean(Object o)` Returns a boolean representation of a given object instance.
`static Iterable<?>`	`asIterable(Object o)` Convert object instance to iterable.
`static boolean`	`equalsAny(Type t, Type... typesToMatch)` Test if a requested type is identity equal with one from a given types list.
`static Class<?>`	`getBoxingClass(Type t)` Get boxing class for requested type.
`static Object`	`getEmptyValue(Type t)` Returns an empty value of requested type.
`static boolean`	`isArray(Object o)` Test if instance is an array.
`static boolean`	`isArray(Type t)` Test if type is array.
`static boolean`	`isArrayLike(Object o)` Test instance if is array like.
`static boolean`	`isArrayLike(Type t)` Test if type is array like, that is, array or collection.
`static boolean`	`isBoolean(Object o)` Test if object instance is a boolean, primitive or boxing class.
`static boolean`	`isBoolean(Type t)` Test if type is a boolean primitive or boxing class.
`static boolean`	`isCharacter(Object o)` Test if instance is a character, primitive or boxing class.
`static boolean`	`isCharacter(Type t)` Test if type is a character, primitive or boxing.
`static boolean`	`isClass(String name)` Test if given name is a valid Java class name.
`static boolean`	`isCollection(Object o)` Test if instance is a collection.
`static boolean`	`isCollection(Type t)` Test if type is collection.
`static boolean`	`isConcrete(Type t)` Test if type is concrete, that is, is not interface or abstract.
`static boolean`	`isDate(Object o)` Test if object is instance of date.
`static boolean`	`isDate(Type t)` Test if type is a calendar date.
`static boolean`	`isEmpty(Object o)` Returns true if given object is empty.
`static boolean`	`isEnum(Object o)` Test if object instance is enumeration.
`static boolean`	`isEnum(Type t)` Test if type is enumeration.
`static boolean`	`isEqual(Type type1, Type type2)` Test two types for equality.
`static boolean`	`isInstanceOf(Object o, Type t)` Test if object instance is not null and extends or implements expected type.
`static boolean`	`isKindOf(Type t, Type... typesToMatch)` Determine if a given type is a kind of one of the requested types to match.
`private static boolean`	`isKindOf(Type t, Type typeToMatch)` Determine if a given type is a kind of a requested type to match.
`static boolean`	`isMap(Object o)` Test if instance is a map.
`static boolean`	`isMap(Type t)` Test if type is map.
`static boolean`	`isNumber(Object o)` Test if object instance is primitive numeric value or related boxing class.
`static boolean`	`isNumber(Type t)` Test if type is numeric.
`static boolean`	`isPrimitive(Object o)` Test if object instance is primitive.
`static boolean`	`isPrimitive(Type t)` Test if type is primitive.
`static boolean`	`isPrimitiveLike(Object o)` Test if object instance is a primitive like.
`static boolean`	`isPrimitiveLike(Type t)` Test if type is like a primitive? Return true only if given type is a number, boolean, enumeration, character or string.
`static boolean`	`isVoid(Type t)` Test if given type is void.
`private static Class<?>`	`typeToClass(Type t)` Cast Java reflective type to language class.

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

- Field Detail
  - BOXING_MAP
```
private static Map<Type,Type> BOXING_MAP
```
    Java language primitive values boxing classes.
  - NUMERICAL_TYPES
```
private static Type[] NUMERICAL_TYPES
```
    Java standard classes used to represent numbers, including primitives.
  - CLASS_NAME_PATTERN
```
private static final Pattern CLASS_NAME_PATTERN
```
    Pattern constant used for Java class name validation.
- Constructor Detail
  - Types
```
protected Types()
```
    Prevent default constructor synthesis but allow sub-classing.
- Method Detail
  - equalsAny
```
public static boolean equalsAny(Type t,
                                Type... typesToMatch)
                         throws IllegalArgumentException
```
    Test if a requested type is identity equal with one from a given types list. If type is null return false. If a type to match happened to be null is considered no match.
    
    Parameters:
    
    t - type to search for, possible null,
    
    typesToMatch - types list to compare with.
    
    Returns:
    
    true if requested type is one from given types list.
    
    Throws:
    
    IllegalArgumentException - if typesToMach is empty.
  - isKindOf
```
public static boolean isKindOf(Type t,
                               Type... typesToMatch)
                        throws IllegalArgumentException
```
    Determine if a given type is a kind of one of the requested types to match. Traverses typesToMatch and delegates isKindOf(Type, Type) till first positive match and returns true. If no match found returns false. If type is null returns false. If a type to match happened to be null is considered no match.
    
    Parameters:
    
    t - type to test, possible null,
    
    typesToMatch - variable number of types to match.
    
    Returns:
    
    true if type is a kind of one of typesToMatch.
    
    Throws:
    
    IllegalArgumentException - if typesToMach is null or empty.
  - isKindOf
```
private static boolean isKindOf(Type t,
                                Type typeToMatch)
```
    Determine if a given type is a kind of a requested type to match. Returns true if type is a subclass or implements typeToMatch - not necessarily direct. Boxing classes for primitive values are compatible. This depart from Class.isAssignableFrom(Class) that consider primitive and related boxing class as different.
    If either type or type to match are parameterized types uses the raw class. If either type or type to match are null returns false.
    
    Parameters:
    
    t - type to test,
    
    typeToMatch - desired type to match.
    
    Returns:
    
    true if type is subclass of or implements typeToMatch.
  - getBoxingClass
```
public static Class<?> getBoxingClass(Type t)
                               throws BugError
```
    Get boxing class for requested type. If type is primitive returns related boxing class. If type is already a boxing type returns it as it is. It is considered a bug if type is not a primitive or a boxing type.
    
    Parameters:
    
    t - primitive or boxing type.
    
    Returns:
    
    boxing class representing requested type.
    
    Throws:
    
    BugError - if type is not a primitive or boxing type.
  - isInstanceOf
```
public static boolean isInstanceOf(Object o,
                                   Type t)
```
    Test if object instance is not null and extends or implements expected type. This predicate consider primitive and related boxing types as equivalent, e.g. 1.23 is instance of Double.
    
    Parameters:
    
    o - object instance to test, possible null,
    
    t - expected type.
    
    Returns:
    
    true if instance is not null and extends or implements requested type.
  - isConcrete
```
public static boolean isConcrete(Type t)
```
    Test if type is concrete, that is, is not interface or abstract. If type to test is parameterized uses its raw type. If type to test is null returns false.
    
    Parameters:
    
    t - type to test, possible null.
    
    Returns:
    
    true if type is concrete.
  - isNumber
```
public static boolean isNumber(Object o)
```
    Test if object instance is primitive numeric value or related boxing class. Returns true if given instance is a primitive numeric value or related boxing class. Returns false if instance is null.
    
    Parameters:
    
    o - object instance, possible null.
    
    Returns:
    
    true if instance is a number.
  - isNumber
```
public static boolean isNumber(Type t)
```
    Test if type is numeric. A type is considered numeric if is a Java standard class representing a number.
    
    Parameters:
    
    t - type to test.
    
    Returns:
    
    true if type is numeric.
  - isCharacter
```
public static boolean isCharacter(Object o)
```
    Test if instance is a character, primitive or boxing class. Not that null is not considered a valid character and this predicate returns false.
    
    Parameters:
    
    o - instance to test.
    
    Returns:
    
    true if instance is a character.
  - isCharacter
```
public static boolean isCharacter(Type t)
```
    Test if type is a character, primitive or boxing.
    
    Parameters:
    
    t - type to test.
    
    Returns:
    
    true if type is character.
  - isBoolean
```
public static boolean isBoolean(Object o)
```
    Test if object instance is a boolean, primitive or boxing class. Returns true if given object is primitive boolean or Boolean instance or false otherwise. Return also false if object is null.
    
    Parameters:
    
    o - object instance, possible null.
    
    Returns:
    
    true if instance to test is boolean.
  - isBoolean
```
public static boolean isBoolean(Type t)
```
    Test if type is a boolean primitive or boxing class.
    
    Parameters:
    
    t - type to test.
    
    Returns:
    
    true if type is boolean.
  - isEnum
```
public static boolean isEnum(Object o)
```
    Test if object instance is enumeration. Returns true if given object is enumeration instance or false otherwise. Returns also false if object is null.
    
    Parameters:
    
    o - object instance to test, possible null.
    
    Returns:
    
    true if instance is enumeration.
  - isEnum
```
public static boolean isEnum(Type t)
```
    Test if type is enumeration. This predicate delegates Class.isEnum() if type is a class. If not, returns false.
    
    Parameters:
    
    t - type to test.
    
    Returns:
    
    true if type is enumeration.
  - isPrimitive
```
public static boolean isPrimitive(Object o)
```
    Test if object instance is primitive. Returns true if given object is primitive instance, false otherwise. Return also false if object is null.
    
    Parameters:
    
    o - object instance to test.
    
    Returns:
    
    true if object instance is primitive.
  - isPrimitive
```
public static boolean isPrimitive(Type t)
```
    Test if type is primitive. Primitive types are those considered so by Class.isPrimitive().
    
    Parameters:
    
    t - type to test.
    
    Returns:
    
    true if type is primitive.
  - isPrimitiveLike
```
public static boolean isPrimitiveLike(Object o)
```
    Test if object instance is a primitive like. This predicates delegates isPrimitiveLike(Type). If instance to test is null returns false.
    
    Parameters:
    
    o - object instance, possible null.
    
    Returns:
    
    true if object instance is primitive like.
  - isPrimitiveLike
```
public static boolean isPrimitiveLike(Type t)
```
    Test if type is like a primitive? Return true only if given type is a number, boolean, enumeration, character or string.
    
    Parameters:
    
    t - type to test.
    
    Returns:
    
    true if this type is like a primitive.
  - isArray
```
public static boolean isArray(Object o)
```
    Test if instance is an array. Delegates isArray(Type) and returns false if object instance is null.
    
    Parameters:
    
    o - instance to test.
    
    Returns:
    
    true if instance is array.
  - isArray
```
public static boolean isArray(Type t)
```
    Test if type is array. If type is a class return Class.isArray() predicate value; otherwise test if type is GenericArrayType.
    
    Parameters:
    
    t - type to test.
    
    Returns:
    
    true if type is array.
  - isArrayLike
```
public static boolean isArrayLike(Object o)
```
    Test instance if is array like. If instance to test is not null delegates isArrayLike(Type); otherwise return false.
    
    Parameters:
    
    o - instance to test, possible null in which case returns false.
    
    Returns:
    
    true if instance is array like; returns false if instance to test is null.
  - isArrayLike
```
public static boolean isArrayLike(Type t)
```
    Test if type is array like, that is, array or collection. Uses isArray(Type) and isCollection(Type).
    
    Parameters:
    
    t - type to test.
    
    Returns:
    
    true if type is array like.
  - isCollection
```
public static boolean isCollection(Object o)
```
    Test if instance is a collection. If instance to test is not null delegates isCollection(Type); otherwise return false.
    
    Parameters:
    
    o - instance to test, possible null in which case returns false.
    
    Returns:
    
    true if instance is collection; returns false if instance to test is null.
  - isCollection
```
public static boolean isCollection(Type t)
```
    Test if type is collection. Returns true if type implements, directly or through inheritance, Collection interface.
    
    Parameters:
    
    t - type to test.
    
    Returns:
    
    true if type is collection.
  - isMap
```
public static boolean isMap(Object o)
```
    Test if instance is a map. If instance to test is not null delegates isMap(Type); otherwise returns false.
    
    Parameters:
    
    o - instance to test, possible null.
    
    Returns:
    
    true if instance is a map; returns false if instance to test is null.
  - isMap
```
public static boolean isMap(Type t)
```
    Test if type is map. Returns true if type implements, directly or through inheritance, Map interface.
    
    Parameters:
    
    t - type to test.
    
    Returns:
    
    true if type is map.
  - isDate
```
public static boolean isDate(Object o)
```
    Test if object is instance of date. Returns true if given object is instance of Date; returns false if instance to test is null.
    
    Parameters:
    
    o - object instance, possible null.
    
    Returns:
    
    true if instance to test is a date.
  - isDate
```
public static boolean isDate(Type t)
```
    Test if type is a calendar date.
    
    Parameters:
    
    t - type to test.
    
    Returns:
    
    true if type is a calendar date.
  - isClass
```
public static boolean isClass(String name)
```
    Test if given name is a valid Java class name. This predicate returns false if name to test is null.
    
    Parameters:
    
    name - name to test, possible null.
    
    Returns:
    
    true if given name is a valid Java class name.
  - asBoolean
```
public static boolean asBoolean(Object o)
```
    Returns a boolean representation of a given object instance. This predicate behavior resemble JavaScript cast of object to boolean value. Here are tested conditions:
    - if isBoolean(Object) returns boolean value,
    - if isNumber(Object) returns true if number is not zero,
    - if instance is string returns true if string is not empty,
    - if isArray(Object), isCollection(Object) or isMap(Object) returns true if is not empty,
    - if isCharacter(Object) returns true if character is defined.
    If object instance is null returns false.
    Parameters:
    
    o - object instance to interpret as boolean.
    
    Returns:
    
    boolean representation of object instance.
  - getEmptyValue
```
public static Object getEmptyValue(Type t)
```
    Returns an empty value of requested type. This method returns 0, false, empty string, current date/time, empty collection or empty array if requested type is respectively a number, boolean, string, date, collection or array. If none of previous returns null.
    
    Parameters:
    
    t - desired type for empty value.
    
    Returns:
    
    empty value.
  - typeToClass
```
private static Class<?> typeToClass(Type t)
```
    Cast Java reflective type to language class. If type is instance of Class just return it. If is parameterized type returns the raw class.
    
    Parameters:
    
    t - Java reflective type.
    
    Returns:
    
    the class described by given type.
  - asIterable
```
public static Iterable<?> asIterable(Object o)
```
    Convert object instance to iterable. If object instance is an array or a collection returns an iterable instance able to iterate array respective collection items. Otherwise return an empty iterable.
    This utility method is designed to be used with foreach loop. Note that if object instance is not iterable foreach loop is not executed.
```
 Object o = getObjectFromSomeSource();
 for(Object item : Types.asIterable(o)) {
   // do something with item instance
 }
 
```
    Parameters:
    
    o - object instance.
    
    Returns:
    
    object iterable, possible empty.
  - isVoid
```
public static boolean isVoid(Type t)
```
    Test if given type is void. Returns true if type is Void.TYPE or Void class, i.e. is void keyword or Void class.
    
    Parameters:
    
    t - type to test for void.
    
    Returns:
    
    true if requested type is void.
  - isEmpty
```
public static boolean isEmpty(Object o)
```
    Returns true if given object is empty. Object is considered empty if:
    - is null,
    - is boolean false,
    - is number zero,
    - is empty string,
    - is empty array, collection or map,
    - is undefined character.
    Parameters:
    
    o - object to test if empty.
    
    Returns:
    
    true if object is empty.
  - isEqual
```
public static boolean isEqual(Type type1,
                              Type type2)
```
    Test two types for equality. This predicate takes care of parameterized types by comparing both raw type and actual type arguments. If an actual type argument is parameterized on its own this method is executed recursively.
    If both types are null returns true.
    
    Parameters:
    
    type1 - first type, null accepted,
    
    type2 - second type, null accepted.
    
    Returns:
    
    true if first type equals the second one.

Class Types

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

BOXING_MAP

NUMERICAL_TYPES

CLASS_NAME_PATTERN

Constructor Detail

Types

Method Detail

equalsAny

isKindOf

isKindOf

getBoxingClass

isInstanceOf

isConcrete

isNumber

isNumber

isCharacter

isCharacter

isBoolean

isBoolean

isEnum

isEnum

isPrimitive

isPrimitive

isPrimitiveLike

isPrimitiveLike

isArray

isArray

isArrayLike

isArrayLike

isCollection

isCollection

isMap

isMap

isDate

isDate

isClass

asBoolean

getEmptyValue

typeToClass

asIterable

isVoid

isEmpty

isEqual