Package org.apache.camel.util

Class ObjectHelper

java.lang.Object

org.apache.camel.util.ObjectHelper

public final class ObjectHelper
extends Object

A number of useful helper methods for working with Objects

Method Summary

Modifier and Type	Method	Description
static void	addListByIndex(List<Object> list, int idx, Object value)	Adds the value to the list at the given index
static int	arrayLength(Object[] pojo)	Used by camel-bean
static List<Object>	asList(Object[] objects)	Turns the input array to a list of objects.
static String	asString(Object[] objects)	Turns the given object arrays into a meaningful string
static <T> T	cast(Class<T> toType, Object value)	Converts the given value to the required type or throw a meaningful exception
static String	classCanonicalName(Object value)	Returns the canonical type name of the given value
static String	className(Object value)	Returns the type name of the given value
static Class<?>	convertPrimitiveTypeToWrapperType(Class<?> type)	Converts primitive types such as int to its wrapper type like Integer
static Class<?>	convertWrapperTypeToPrimitiveType(Class<?> type)	Converts wrapper type like Integer to its primitive type, i.e.
static Iterable<Throwable>	createExceptionIterable(Throwable exception)	Creates an Iterable to walk the exception from the bottom up (the last caused by going upwards to the root exception).
static Iterator<Throwable>	createExceptionIterator(Throwable exception)	Creates an Iterator to walk the exception from the bottom up (the last caused by going upwards to the root exception).
static boolean	equal(Object a, Object b)	A helper method for comparing objects for equality while handling nulls
static boolean	equal(Object a, Object b, boolean ignoreCase)	A helper method for comparing objects for equality while handling nulls
static boolean	equalByteArray(byte[] a, byte[] b)	A helper method for comparing byte arrays for equality while handling nulls
static boolean	equalIgnoreCase(Object a, Object b)	A helper method for comparing objects for equality while handling case insensitivity
static boolean	evaluateValuePredicate(Object value)	Evaluate the value as a predicate which attempts to convert the value to a boolean otherwise true is returned if the value is not null
static List<Method>	findMethodsWithAnnotation(Class<?> type, Class<? extends Annotation> annotationType)	Returns a list of methods which are annotated with the given annotation
static List<Method>	findMethodsWithAnnotation(Class<?> type, Class<? extends Annotation> annotationType, boolean checkMetaAnnotations)	Returns a list of methods which are annotated with the given annotation
static Optional<Object>	firstNotNull(Object... values)	Returns the first non null object null.
static <A extends Annotation> A	getAnnotation(Object instance, Class<A> type)	Gets the annotation from the given instance.
static String	getDefaultCharacterSet()	Helper method to return the default character set name
static <T> T	getException(Class<T> type, Throwable exception)	Retrieves the given exception type from the exception.
static String	getIdentityHashCode(Object object)
static String	getPropertyName(Method method)	Returns the Java Bean property name of the given method, if it is a setter
static boolean	getSystemProperty(String name, Boolean defaultValue)	A helper method to access a boolean system property, catching any security exceptions
static String	getSystemProperty(String name, String defaultValue)	A helper method to access a system property, catching any security exceptions
static boolean	hasAnnotation(Annotation[] annotations, Class<?> type)	Returns true if the given collection of annotations matches the given type
static boolean	hasAnnotation(AnnotatedElement elem, Class<? extends Annotation> annotationType, boolean checkMetaAnnotations)	Checks if a Class or Method are annotated with the given annotation
static boolean	hasDefaultNoArgConstructor(Class<?> type)	Does the given class have a default no-arg constructor (public or inherited).
static boolean	hasDefaultPublicNoArgConstructor(Class<?> type)	Does the given class have a default public no-arg constructor.
static <T> void	ifNotEmpty(T value, Consumer<T> consumer)	Tests whether the value is not null, an empty string, an empty collection or a map
static boolean	isAssignableFrom(Class<?> a, Class<?> b)	Returns true if a class is assignable from another class like the Class.isAssignableFrom(Class) method but which also includes coercion between primitive types to deal with Java 5 primitive type wrapping
static boolean	isEmpty(String value)	Tests whether the value is null or an empty string or an empty collection/map.
static boolean	isEmpty(Collection<?> value)	Tests whether the value is null or an an empty collection
static boolean	isEmpty(Map<?,?> value)	Tests whether the value is null or an an empty map
static <T> boolean	isEmpty(T value)	Tests whether the value is null, an empty string or an empty collection/map.
static boolean	isEqualToAny(Object object, Object... values)	Returns true if the given object is equal to any of the expected value
static boolean	isNaN(Object value)	Is the given value a numeric NaN type
static boolean	isNotEmpty(String value)	Tests whether the value is not null or an empty string
static boolean	isNotEmpty(Collection<?> value)	Tests whether the value is null or an an empty collection
static boolean	isNotEmpty(Map<?,?> value)	Tests whether the value is null or an an empty map
static <T> boolean	isNotEmpty(T value)	Tests whether the value is not null, an empty string or an empty collection/map.
static boolean	isOverridingMethod(Class<?> inheritingClass, Method source, Method target, boolean exact)	Tests whether the target method overrides the source method from the inheriting class.
static boolean	isOverridingMethod(Method source, Method target)	Tests whether the target method overrides the source method.
static boolean	isOverridingMethod(Method source, Method target, boolean exact)	Tests whether the target method overrides the source method.
static boolean	isPrimitiveArrayType(Class<?> clazz)	Returns if the given clazz type is a Java primitive array type.
static boolean	isSubclass(Class<?> clazz, Class<?> subClass)	Checks if the given class has a subclass (extends or implements)
static Class<?>	loadClass(String name)	Attempts to load the given class name using the thread context class loader or the class loader used to load this class
static Class<?>	loadClass(String name, ClassLoader loader)	Attempts to load the given class name using the thread context class loader or the given class loader
static Class<?>	loadClass(String name, ClassLoader loader, boolean needToWarn)	Attempts to load the given class name using the thread context class loader or the given class loader
static InputStream	loadResourceAsStream(String name)	Attempts to load the given resource as a stream using the thread context class loader or the class loader used to load this class
static InputStream	loadResourceAsStream(String name, ClassLoader loader)	Attempts to load the given resource as a stream using first the given class loader, then the thread context class loader and finally the class loader used to load this class
static URL	loadResourceAsURL(String name)	Attempts to load the given resource as a stream using the thread context class loader or the class loader used to load this class
static URL	loadResourceAsURL(String name, ClassLoader loader)	Attempts to load the given resource as a stream using the thread context class loader or the class loader used to load this class
static Enumeration<URL>	loadResourcesAsURL(String uri)	Attempts to load the given resources from the given package name using the thread context class loader or the class loader used to load this class
static Enumeration<URL>	loadResourcesAsURL(String uri, ClassLoader loader)	Attempts to load the given resources from the given package name using the thread context class loader or the class loader used to load this class
static Class<?>	loadSimpleType(String name)	Load a simple type
static String	lookupConstantFieldValue(Class<?> clazz, String name)	Lookup the constant field on the given class with the given name
static boolean	matches(List<?> list)	Returns the predicate matching boolean on a List result set where if the first element is a boolean its value is used otherwise this method returns true if the collection is not empty
static String	name(Class<?> type)	Returns the type name of the given type or null if the type variable is null
static <T> T	notNull(T value, String name)	Asserts whether the value is not null
static <T> T	notNull(T value, String name, Object on)	Asserts whether the value is not null
static <T> T	supplyIfEmpty(T value, Supplier<T> supplier)	Tests whether the value is null, an empty string, an empty collection or a map
static Boolean	toBoolean(Object value)
static Object	type(Object bean)	Returns the type of the given object or null if the value is null
static RuntimeException	wrapRuntimeCamelException(Throwable e)	Deprecated. Use org.apache.camel.RuntimeCamelException#wrapRuntimeCamelException instead

Methods inherited from class java.lang.Object

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

Method Detail

equal

public static boolean equal(Object a,
                            Object b)

A helper method for comparing objects for equality while handling nulls

equalIgnoreCase

public static boolean equalIgnoreCase(Object a,
                                      Object b)

A helper method for comparing objects for equality while handling case insensitivity

equal

public static boolean equal(Object a,
                            Object b,
                            boolean ignoreCase)

A helper method for comparing objects for equality while handling nulls

equalByteArray

public static boolean equalByteArray(byte[] a,
                                     byte[] b)

A helper method for comparing byte arrays for equality while handling nulls

isEqualToAny

public static boolean isEqualToAny(Object object,
                                   Object... values)

Returns true if the given object is equal to any of the expected value

toBoolean

public static Boolean toBoolean(Object value)

notNull

public static <T> T notNull(T value,
                            String name)

Asserts whether the value is not null

Parameters:

value - the value to test

name - the key that resolved the value

Returns:

the passed value as is

Throws:

IllegalArgumentException - is thrown if assertion fails

notNull

public static <T> T notNull(T value,
                            String name,
                            Object on)

Asserts whether the value is not null

Parameters:

value - the value to test

on - additional description to indicate where this problem occurred (appended as toString())

name - the key that resolved the value

Returns:

the passed value as is

Throws:

IllegalArgumentException - is thrown if assertion fails

isEmpty

public static boolean isEmpty(String value)

Tests whether the value is null or an empty string or an empty collection/map.

Parameters:

value - the value, if its a String it will be tested for text length as well

Returns:

true if empty

isEmpty

public static boolean isEmpty(Collection<?> value)

Tests whether the value is null or an an empty collection

Parameters:

value - the value to test

Returns:

true if empty

isEmpty

public static boolean isEmpty(Map<?,?> value)

Tests whether the value is null or an an empty map

Parameters:

value - the value to test

Returns:

true if empty

isEmpty

public static <T> boolean isEmpty(T value)

Tests whether the value is null, an empty string or an empty collection/map.

Parameters:

value - the value, if its a String it will be tested for text length as well

Returns:

true if empty

isNotEmpty

public static <T> boolean isNotEmpty(T value)

Tests whether the value is not null, an empty string or an empty collection/map.

Parameters:

value - the value, if its a String it will be tested for text length as well

Returns:

true if not empty

isNotEmpty

public static boolean isNotEmpty(String value)

Tests whether the value is not null or an empty string

Parameters:

value - the value, if its a String it will be tested for text length as well

Returns:

true if not empty

isNotEmpty

public static boolean isNotEmpty(Collection<?> value)

Tests whether the value is null or an an empty collection

Parameters:

value - the value to test

Returns:

true if empty

isNotEmpty

public static boolean isNotEmpty(Map<?,?> value)

Tests whether the value is null or an an empty map

Parameters:

value - the value to test

Returns:

true if empty

firstNotNull

public static Optional<Object> firstNotNull(Object... values)

Returns the first non null object null.

Parameters:

values - the values

Returns:

an Optional

supplyIfEmpty

public static <T> T supplyIfEmpty(T value,
                                  Supplier<T> supplier)

Tests whether the value is null, an empty string, an empty collection or a map

Parameters:

value - the value, if its a String it will be tested for text length as well

supplier - the supplier, the supplier to be used to get a value if value is null

ifNotEmpty

public static <T> void ifNotEmpty(T value,
                                  Consumer<T> consumer)

Tests whether the value is not null, an empty string, an empty collection or a map

Parameters:

value - the value, if its a String it will be tested for text length as well

consumer - the consumer, the operation to be executed against value if not empty

matches

public static boolean matches(List<?> list)

Returns the predicate matching boolean on a List result set where if the first element is a boolean its value is used otherwise this method returns true if the collection is not empty

Returns:

true if the first element is a boolean and its value is true or if the list is non empty

getSystemProperty

public static String getSystemProperty(String name,
                                       String defaultValue)

A helper method to access a system property, catching any security exceptions

Parameters:

name - the name of the system property required

defaultValue - the default value to use if the property is not available or a security exception prevents access

Returns:

the system property value or the default value if the property is not available or security does not allow its access

getSystemProperty

public static boolean getSystemProperty(String name,
                                        Boolean defaultValue)

A helper method to access a boolean system property, catching any security exceptions

Parameters:

name - the name of the system property required

defaultValue - the default value to use if the property is not available or a security exception prevents access

Returns:

the boolean representation of the system property value or the default value if the property is not available or security does not allow its access

name

public static String name(Class<?> type)

Returns the type name of the given type or null if the type variable is null

className

public static String className(Object value)

Returns the type name of the given value

classCanonicalName

public static String classCanonicalName(Object value)

Returns the canonical type name of the given value

loadClass

public static Class<?> loadClass(String name)

Attempts to load the given class name using the thread context class loader or the class loader used to load this class

Parameters:

name - the name of the class to load

Returns:

the class or null if it could not be loaded

loadClass

public static Class<?> loadClass(String name,
                                 ClassLoader loader)

Attempts to load the given class name using the thread context class loader or the given class loader

Parameters:

name - the name of the class to load

loader - the class loader to use after the thread context class loader

Returns:

the class or null if it could not be loaded

loadClass

public static Class<?> loadClass(String name,
                                 ClassLoader loader,
                                 boolean needToWarn)

Attempts to load the given class name using the thread context class loader or the given class loader

Parameters:

name - the name of the class to load

loader - the class loader to use after the thread context class loader

needToWarn - when true logs a warning when a class with the given name could not be loaded

Returns:

the class or null if it could not be loaded

loadSimpleType

public static Class<?> loadSimpleType(String name)

Load a simple type

Parameters:

name - the name of the class to load

Returns:

the class or null if it could not be loaded

loadResourceAsStream

public static InputStream loadResourceAsStream(String name)

Attempts to load the given resource as a stream using the thread context class loader or the class loader used to load this class

Parameters:

name - the name of the resource to load

Returns:

the stream or null if it could not be loaded

loadResourceAsStream

public static InputStream loadResourceAsStream(String name,
                                               ClassLoader loader)

Attempts to load the given resource as a stream using first the given class loader, then the thread context class loader and finally the class loader used to load this class

Parameters:

name - the name of the resource to load

loader - optional classloader to attempt first

Returns:

the stream or null if it could not be loaded

loadResourceAsURL

public static URL loadResourceAsURL(String name)

Attempts to load the given resource as a stream using the thread context class loader or the class loader used to load this class

Parameters:

name - the name of the resource to load

Returns:

the stream or null if it could not be loaded

loadResourceAsURL

public static URL loadResourceAsURL(String name,
                                    ClassLoader loader)

Attempts to load the given resource as a stream using the thread context class loader or the class loader used to load this class

Parameters:

name - the name of the resource to load

loader - optional classloader to attempt first

Returns:

the stream or null if it could not be loaded

loadResourcesAsURL

public static Enumeration<URL> loadResourcesAsURL(String uri)

Attempts to load the given resources from the given package name using the thread context class loader or the class loader used to load this class

Parameters:

uri - the name of the package to load its resources

Returns:

the URLs for the resources or null if it could not be loaded

loadResourcesAsURL

public static Enumeration<URL> loadResourcesAsURL(String uri,
                                                  ClassLoader loader)

Attempts to load the given resources from the given package name using the thread context class loader or the class loader used to load this class

Parameters:

uri - the name of the package to load its resources

loader - optional classloader to attempt first

Returns:

the URLs for the resources or null if it could not be loaded

isOverridingMethod

public static boolean isOverridingMethod(Method source,
                                         Method target)

Tests whether the target method overrides the source method.

Tests whether they have the same name, return type, and parameter list.

Parameters:

source - the source method

target - the target method

Returns:

true if it override, false otherwise

isOverridingMethod

public static boolean isOverridingMethod(Method source,
                                         Method target,
                                         boolean exact)

Tests whether the target method overrides the source method.

Tests whether they have the same name, return type, and parameter list.

Parameters:

source - the source method

target - the target method

exact - true if the override must be exact same types, false if the types should be assignable

Returns:

true if it override, false otherwise

isOverridingMethod

public static boolean isOverridingMethod(Class<?> inheritingClass,
                                         Method source,
                                         Method target,
                                         boolean exact)

Tests whether the target method overrides the source method from the inheriting class.

Tests whether they have the same name, return type, and parameter list.

Parameters:

inheritingClass - the class inheriting the target method overriding the source method

source - the source method

target - the target method

exact - true if the override must be exact same types, false if the types should be assignable

Returns:

true if it override, false otherwise

findMethodsWithAnnotation

public static List<Method> findMethodsWithAnnotation(Class<?> type,
                                                     Class<? extends Annotation> annotationType)

Returns a list of methods which are annotated with the given annotation

Parameters:

type - the type to reflect on

annotationType - the annotation type

Returns:

a list of the methods found

findMethodsWithAnnotation

public static List<Method> findMethodsWithAnnotation(Class<?> type,
                                                     Class<? extends Annotation> annotationType,
                                                     boolean checkMetaAnnotations)

Returns a list of methods which are annotated with the given annotation

Parameters:

type - the type to reflect on

annotationType - the annotation type

checkMetaAnnotations - check for meta annotations

Returns:

a list of the methods found

hasAnnotation

public static boolean hasAnnotation(AnnotatedElement elem,
                                    Class<? extends Annotation> annotationType,
                                    boolean checkMetaAnnotations)

Checks if a Class or Method are annotated with the given annotation

Parameters:

elem - the Class or Method to reflect on

annotationType - the annotation type

checkMetaAnnotations - check for meta annotations

Returns:

true if annotations is present

asString

public static String asString(Object[] objects)

Turns the given object arrays into a meaningful string

Parameters:

objects - an array of objects or null

Returns:

a meaningful string

isAssignableFrom

public static boolean isAssignableFrom(Class<?> a,
                                       Class<?> b)

Returns true if a class is assignable from another class like the Class.isAssignableFrom(Class) method but which also includes coercion between primitive types to deal with Java 5 primitive type wrapping

isPrimitiveArrayType

public static boolean isPrimitiveArrayType(Class<?> clazz)

Returns if the given clazz type is a Java primitive array type.

Parameters:

clazz - the Java type to be checked

Returns:

true if the given type is a Java primitive array type

isSubclass

public static boolean isSubclass(Class<?> clazz,
                                 Class<?> subClass)

Checks if the given class has a subclass (extends or implements)

Parameters:

clazz - the class

subClass - the subclass (class or interface)

arrayLength

public static int arrayLength(Object[] pojo)

Used by camel-bean

convertPrimitiveTypeToWrapperType

public static Class<?> convertPrimitiveTypeToWrapperType(Class<?> type)

Converts primitive types such as int to its wrapper type like Integer

convertWrapperTypeToPrimitiveType

public static Class<?> convertWrapperTypeToPrimitiveType(Class<?> type)

Converts wrapper type like Integer to its primitive type, i.e. int.

getDefaultCharacterSet

public static String getDefaultCharacterSet()

Helper method to return the default character set name

getPropertyName

public static String getPropertyName(Method method)

Returns the Java Bean property name of the given method, if it is a setter

hasAnnotation

public static boolean hasAnnotation(Annotation[] annotations,
                                    Class<?> type)

Returns true if the given collection of annotations matches the given type

getAnnotation

public static <A extends Annotation> A getAnnotation(Object instance,
                                                     Class<A> type)

Gets the annotation from the given instance.

Parameters:

instance - the instance

type - the annotation

Returns:

the annotation, or null if the instance does not have the given annotation

cast

public static <T> T cast(Class<T> toType,
                         Object value)

Converts the given value to the required type or throw a meaningful exception

hasDefaultPublicNoArgConstructor

public static boolean hasDefaultPublicNoArgConstructor(Class<?> type)

Does the given class have a default public no-arg constructor.

hasDefaultNoArgConstructor

public static boolean hasDefaultNoArgConstructor(Class<?> type)

Does the given class have a default no-arg constructor (public or inherited).

type

public static Object type(Object bean)

Returns the type of the given object or null if the value is null

evaluateValuePredicate

public static boolean evaluateValuePredicate(Object value)

Evaluate the value as a predicate which attempts to convert the value to a boolean otherwise true is returned if the value is not null

createExceptionIterable

public static Iterable<Throwable> createExceptionIterable(Throwable exception)

Creates an Iterable to walk the exception from the bottom up (the last caused by going upwards to the root exception).

Parameters:

exception - the exception

Returns:

the Iterable

See Also:

Iterable

createExceptionIterator

public static Iterator<Throwable> createExceptionIterator(Throwable exception)

Creates an Iterator to walk the exception from the bottom up (the last caused by going upwards to the root exception).

Parameters:

exception - the exception

Returns:

the Iterator

See Also:

Iterator

getException

public static <T> T getException(Class<T> type,
                                 Throwable exception)

Retrieves the given exception type from the exception.

Is used to get the caused exception that typically have been wrapped in some sort of Camel wrapper exception

The strategy is to look in the exception hierarchy to find the first given cause that matches the type. Will start from the bottom (the real cause) and walk upwards.

Parameters:

type - the exception type wanted to retrieve

exception - the caused exception

Returns:

the exception found (or null if not found in the exception hierarchy)

getIdentityHashCode

public static String getIdentityHashCode(Object object)

lookupConstantFieldValue

public static String lookupConstantFieldValue(Class<?> clazz,
                                              String name)

Lookup the constant field on the given class with the given name

Parameters:

clazz - the class

name - the name of the field to lookup

Returns:

the value of the constant field, or null if not found

isNaN

public static boolean isNaN(Object value)

Is the given value a numeric NaN type

Parameters:

value - the value

Returns:

true if its a Float.NaN or Double.NaN.

wrapRuntimeCamelException

@Deprecated
public static RuntimeException wrapRuntimeCamelException(Throwable e)

Deprecated.

Use org.apache.camel.RuntimeCamelException#wrapRuntimeCamelException instead

Wraps the caused exception in a RuntimeException if its not already such an exception.

Parameters:

e - the caused exception

Returns:

the wrapper exception

asList

public static List<Object> asList(Object[] objects)

Turns the input array to a list of objects.

Parameters:

objects - an array of objects or null

Returns:

an object list

addListByIndex

public static void addListByIndex(List<Object> list,
                                  int idx,
                                  Object value)

Adds the value to the list at the given index