Package org.cyclos.utils

Class ObjectHelper

java.lang.Object

org.cyclos.utils.ObjectHelper

public class ObjectHelper
extends Object

Helper class for objects

Constructor Summary

Constructors

Constructor	Description
ObjectHelper()

Method Summary

Modifier and Type	Method	Description
static boolean	anyIsNull(Object... elements)	Returns true if some element is null.
static boolean	areAllNulls(Object... elements)	Returns true if all elements are null.
static <T> T	coalesce(T... values)	Returns the first non-null value
static <T extends Comparable<T>> int	compare(T o1, T o2)	Compares 2 Comparables, handling nulls
static <T,R> R	defaultValue(R object, T fstArg, Function<T,R> whenNull)	Lazy version of defaultValue(Object, Object) but accepting an argument that will be passed to the function (invoked ONLY if the first parameter is null).
static <T,U,R> R	defaultValue(R object, T fstArg, U sndArg, BiFunction<T,U,R> whenNull)	Same as defaultValue(Object, Object, Function) but accepting two arguments
static <T> T	defaultValue(T object, Supplier<T> whenNull)	Lazy version of defaultValue(Object, Object)
static <T> T	defaultValue(T object, T whenNull)	Returns the second parameter when the first is null
static Object	emptyToNull(Object value)	If the given value is empty (see isEmpty(Object object)) returns null, otherwise returns the same value.
static boolean	equalsOrBothNull(Object first, Object second)	Returns true when either both objects are non null and equals or both null
static int	hashCode(Object object)	Returns the hashCode of the given object, handling nulls (-1 if null)
static <T> T	ifType(Object object, Class<T> expectedType)	Returns the argument if it is an instance of the given class, otherwise null
static boolean	isEmpty(Object object)	Returns whether the given object is null or an empty string, collection, map or array
static boolean	isNotEmpty(Object object)	Negated value of isEmpty(Object)
static boolean	isNotOneOf(Object element, Object... objects)	Returns true if element is not one of the given objects.
static boolean	isOneOf(Object element, Object... objects)	Returns true if element is one of the objects If element or objects are null it returns false;
static void	requireOneOf(Object element, Object... objects)
static void	requireOneOf(Supplier<String> errorMessageSupplier, Object element, Object... objects)	Checks if element is one of the objects

Methods inherited from class java.lang.Object

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

Constructor Detail

ObjectHelper

public ObjectHelper()

Method Detail

anyIsNull

public static boolean anyIsNull(Object... elements)

Returns true if some element is null. If elements is empty or null then returns true.

areAllNulls

public static boolean areAllNulls(Object... elements)

Returns true if all elements are null. If elements is empty or null then returns true.

coalesce

@SafeVarargs
public static <T> T coalesce(T... values)

Returns the first non-null value

compare

public static <T extends Comparable<T>> int compare(T o1,
                                                    T o2)

Compares 2 Comparables, handling nulls

defaultValue

public static <T,R> R defaultValue(R object,
                                         T fstArg,
                                         Function<T,R> whenNull)

Lazy version of defaultValue(Object, Object) but accepting an argument that will be passed to the function (invoked ONLY if the first parameter is null). This will allow use lambda expressions an method references.

defaultValue

public static <T,U,R> R defaultValue(R object,
                                                 T fstArg,
                                                 U sndArg,
                                                 BiFunction<T,U,R> whenNull)

Same as defaultValue(Object, Object, Function) but accepting two arguments

See Also:

defaultValue(Object, Object, Function)

defaultValue

public static <T> T defaultValue(T object,
                                 Supplier<T> whenNull)

Lazy version of defaultValue(Object, Object)

defaultValue

public static <T> T defaultValue(T object,
                                 T whenNull)

Returns the second parameter when the first is null

emptyToNull

public static Object emptyToNull(Object value)

If the given value is empty (see isEmpty(Object object)) returns null, otherwise returns the same value.

equalsOrBothNull

public static boolean equalsOrBothNull(Object first,
                                       Object second)

Returns true when either both objects are non null and equals or both null

hashCode

public static int hashCode(Object object)

Returns the hashCode of the given object, handling nulls (-1 if null)

ifType

public static <T> T ifType(Object object,
                           Class<T> expectedType)

Returns the argument if it is an instance of the given class, otherwise null

isEmpty

public static boolean isEmpty(Object object)

Returns whether the given object is null or an empty string, collection, map or array

isNotEmpty

public static boolean isNotEmpty(Object object)

Negated value of isEmpty(Object)

isNotOneOf

public static boolean isNotOneOf(Object element,
                                 Object... objects)

Returns true if element is not one of the given objects. If element or objects are null it returns false;

isOneOf

public static boolean isOneOf(Object element,
                              Object... objects)

Returns true if element is one of the objects If element or objects are null it returns false;

requireOneOf

public static void requireOneOf(Object element,
                                Object... objects)
                         throws IllegalArgumentException

Throws:

IllegalArgumentException

requireOneOf

public static void requireOneOf(Supplier<String> errorMessageSupplier,
                                Object element,
                                Object... objects)
                         throws IllegalArgumentException

Checks if element is one of the objects

Parameters:

errorMessageSupplier - (Optional) Supplier to get the message in case of error

Throws:

IllegalArgumentException - if element is not one of the given objects.