org.springframework.beans
Class BeanUtils

java.lang.Object
  org.springframework.beans.BeanUtils

public abstract class BeanUtils

extends Object

Static convenience methods for JavaBeans, for instantiating beans, copying bean properties, etc.

Mainly for use within the framework, but to some degree also useful for application classes.

Author:

Rod Johnson, Juergen Hoeller, Rob Harrop

Constructor Summary

BeanUtils()

Method Summary

static void	copyProperties(Object source, Object target) Copy the property values of the given source bean into the target bean.
static void	copyProperties(Object source, Object target, String[] ignoreProperties) Copy the property values of the given source bean into the given target bean, ignoring the given ignoreProperties.
static Method	findDeclaredMethod(Class clazz, String methodName, Class[] paramTypes) Find a method with the given method name and the given parameter types, declared on the given class or one of its superclasses.
static Method	findDeclaredMethodWithMinimalParameters(Class clazz, String methodName) Find a method with the given method name and minimal parameters (best case: none), declared on the given class or one of its superclasses.
static Method	findMethod(Class clazz, String methodName, Class[] paramTypes) Find a method with the given method name and the given parameter types, declared on the given class or one of its superclasses.
static Method	findMethodWithMinimalParameters(Class clazz, String methodName) Find a method with the given method name and minimal parameters (best case: none), declared on the given class or one of its superclasses.
static PropertyDescriptor	findPropertyForMethod(Method method) Find a JavaBeans PropertyDescriptor for the given method, with the method either being the read method or the write method for that bean property.
static PropertyDescriptor[]	getPropertyDescriptors(Class clazz) Retrieve the JavaBeans PropertyDescriptors of a given class.
static Object	instantiateClass(Class clazz) Convenience method to instantiate a class using its no-arg constructor.
static Object	instantiateClass(Constructor ctor, Object[] args) Convenience method to instantiate a class using the given constructor.
static boolean	isAssignable(Class targetType, Class valueType) Determine if the given target type is assignable from the given value type, assuming setting by reflection.
static boolean	isAssignable(Class type, Object value) Determine if the given type is assignable from the given value, assuming setting by reflection.
static boolean	isPrimitiveArray(Class clazz) Check if the given class represents a primitive array, i.e. boolean, byte, char, short, int, long, float, or double.
static boolean	isPrimitiveWrapperArray(Class clazz) Check if the given class represents an array of primitive wrappers, i.e.
static boolean	isSimpleProperty(Class clazz) Check if the given class represents a "simple" property, i.e. a primitive, a String, a Class, or a corresponding array.

Methods inherited from class java.lang.Object

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

Constructor Detail

BeanUtils

public BeanUtils()

Method Detail

instantiateClass

public static Object instantiateClass(Class clazz)
                               throws BeansException

Convenience method to instantiate a class using its no-arg constructor. As this method doesn't try to load classes by name, it should avoid class-loading issues.

Note that this method tries to set the constructor accessible if given a non-accessible (i.e. non-public) constructor.

Parameters:

clazz - class to instantiate

Returns:

the new instance

Throws:

BeansException

instantiateClass

public static Object instantiateClass(Constructor ctor,
                                      Object[] args)
                               throws BeansException

Convenience method to instantiate a class using the given constructor. As this method doesn't try to load classes by name, it should avoid class-loading issues.

Note that this method tries to set the constructor accessible if given a non-accessible (i.e. non-public) constructor.

Parameters:

ctor - constructor to instantiate

Returns:

the new instance

Throws:

BeansException

findMethod

public static Method findMethod(Class clazz,
                                String methodName,
                                Class[] paramTypes)

Find a method with the given method name and the given parameter types, declared on the given class or one of its superclasses. Prefers public methods, but will return a protected, package access, or private method too.

Checks Class.getMethod first, falling back to findDeclaredMethod. This allows to find public methods without issues even in environments with restricted Java security settings.

Parameters:

clazz - the class to check

methodName - the name of the method to find

paramTypes - the parameter types of the method to find

Returns:

the method object, or null if not found

See Also:

Class.getMethod(java.lang.String, java.lang.Class[]), findDeclaredMethod(java.lang.Class, java.lang.String, java.lang.Class[])

findDeclaredMethod

public static Method findDeclaredMethod(Class clazz,
                                        String methodName,
                                        Class[] paramTypes)

Find a method with the given method name and the given parameter types, declared on the given class or one of its superclasses. Will return a public, protected, package access, or private method.

Checks Class.getDeclaredMethod, cascading upwards to all superclasses.

Parameters:

clazz - the class to check

methodName - the name of the method to find

paramTypes - the parameter types of the method to find

Returns:

the method object, or null if not found

See Also:

Class.getDeclaredMethod(java.lang.String, java.lang.Class[])

findMethodWithMinimalParameters

public static Method findMethodWithMinimalParameters(Class clazz,
                                                     String methodName)

Find a method with the given method name and minimal parameters (best case: none), declared on the given class or one of its superclasses. Prefers public methods, but will return a protected, package access, or private method too.

Checks Class.getMethods first, falling back to findDeclaredMethodWithMinimalParameters. This allows to find public methods without issues even in environments with restricted Java security settings.

Parameters:

clazz - the class to check

methodName - the name of the method to find

Returns:

the method object, or null if not found

See Also:

Class.getMethods(), findDeclaredMethodWithMinimalParameters(java.lang.Class, java.lang.String)

findDeclaredMethodWithMinimalParameters

public static Method findDeclaredMethodWithMinimalParameters(Class clazz,
                                                             String methodName)

Find a method with the given method name and minimal parameters (best case: none), declared on the given class or one of its superclasses. Will return a public, protected, package access, or private method.

Checks Class.getDeclaredMethods, cascading upwards to all superclasses.

Parameters:

clazz - the class to check

methodName - the name of the method to find

Returns:

the method object, or null if not found

See Also:

Class.getDeclaredMethods()

isAssignable

public static boolean isAssignable(Class type,
                                   Object value)

Determine if the given type is assignable from the given value, assuming setting by reflection. Considers primitive wrapper classes as assignable to the corresponding primitive types.

For example used in a bean factory's constructor resolution.

Parameters:

type - the target type

value - the value that should be assigned to the type

Returns:

if the type is assignable from the value

isAssignable

public static boolean isAssignable(Class targetType,
                                   Class valueType)

Determine if the given target type is assignable from the given value type, assuming setting by reflection. Considers primitive wrapper classes as assignable to the corresponding primitive types.

For example used in BeanWrapperImpl's custom editor matrching.

Parameters:

targetType - the target type

valueType - the value type that should be assigned to the target type

Returns:

if the target type is assignable from the value type

isSimpleProperty

public static boolean isSimpleProperty(Class clazz)

Check if the given class represents a "simple" property, i.e. a primitive, a String, a Class, or a corresponding array. Used to determine properties to check for a "simple" dependency-check.

See Also:

AbstractBeanDefinition.DEPENDENCY_CHECK_SIMPLE, AbstractAutowireCapableBeanFactory.dependencyCheck(java.lang.String, org.springframework.beans.factory.support.RootBeanDefinition, org.springframework.beans.BeanWrapper, org.springframework.beans.PropertyValues)

isPrimitiveArray

public static boolean isPrimitiveArray(Class clazz)

Check if the given class represents a primitive array, i.e. boolean, byte, char, short, int, long, float, or double.

isPrimitiveWrapperArray

public static boolean isPrimitiveWrapperArray(Class clazz)

Check if the given class represents an array of primitive wrappers, i.e. Boolean, Byte, Character, Short, Integer, Long, Float, or Double.

copyProperties

public static void copyProperties(Object source,
                                  Object target)
                           throws IllegalArgumentException,
                                  BeansException

Copy the property values of the given source bean into the target bean.

Parameters:

source - source bean

target - target bean

Throws:

IllegalArgumentException - if the classes of source and target do not match

BeansException

copyProperties

public static void copyProperties(Object source,
                                  Object target,
                                  String[] ignoreProperties)
                           throws IllegalArgumentException,
                                  BeansException

Copy the property values of the given source bean into the given target bean, ignoring the given ignoreProperties.

Parameters:

source - the source bean

target - the target bean

ignoreProperties - array of property names to ignore

Throws:

IllegalArgumentException - if the classes of source and target do not match

BeansException

getPropertyDescriptors

public static PropertyDescriptor[] getPropertyDescriptors(Class clazz)
                                                   throws BeansException

Retrieve the JavaBeans PropertyDescriptors of a given class.

Parameters:

clazz - the Class to retrieve the PropertyDescriptors for

Returns:

an array of PropertyDescriptors for the given class

Throws:

BeansException - if PropertyDescriptor look fails

findPropertyForMethod

public static PropertyDescriptor findPropertyForMethod(Method method)
                                                throws BeansException

Find a JavaBeans PropertyDescriptor for the given method, with the method either being the read method or the write method for that bean property.

Parameters:

method - the method to find a corresponding PropertyDescriptor for

Returns:

the corresponding PropertyDescriptor, or null if none

Throws:

BeansException - if PropertyDescriptor look fails