Spring Framework

org.springframework.beans
Class BeanUtils

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

public abstract class BeanUtils
extends java.lang.Object

Static convenience methods for JavaBeans: for instantiating beans, checking bean property types, 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, Sam Brannen

Constructor Summary
BeanUtils()
           
 
Method Summary
static void copyProperties(java.lang.Object source, java.lang.Object target)
          Copy the property values of the given source bean into the target bean.
static void copyProperties(java.lang.Object source, java.lang.Object target, java.lang.Class<?> editable)
          Copy the property values of the given source bean into the given target bean, only setting properties defined in the given "editable" class (or interface).
static void copyProperties(java.lang.Object source, java.lang.Object target, java.lang.String[] ignoreProperties)
          Copy the property values of the given source bean into the given target bean, ignoring the given "ignoreProperties".
static java.lang.reflect.Method findDeclaredMethod(java.lang.Class<?> clazz, java.lang.String methodName, java.lang.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 java.lang.reflect.Method findDeclaredMethodWithMinimalParameters(java.lang.Class<?> clazz, java.lang.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 java.beans.PropertyEditor findEditorByConvention(java.lang.Class<?> targetType)
          Find a JavaBeans PropertyEditor following the 'Editor' suffix convention (e.g.
static java.lang.reflect.Method findMethod(java.lang.Class<?> clazz, java.lang.String methodName, java.lang.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 java.lang.reflect.Method findMethodWithMinimalParameters(java.lang.Class<?> clazz, java.lang.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 java.lang.reflect.Method findMethodWithMinimalParameters(java.lang.reflect.Method[] methods, java.lang.String methodName)
          Find a method with the given method name and minimal parameters (best case: none) in the given list of methods.
static java.beans.PropertyDescriptor findPropertyForMethod(java.lang.reflect.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 java.lang.Class<?> findPropertyType(java.lang.String propertyName, java.lang.Class<?>[] beanClasses)
          Determine the bean property type for the given property from the given classes/interfaces, if possible.
static java.beans.PropertyDescriptor getPropertyDescriptor(java.lang.Class<?> clazz, java.lang.String propertyName)
          Retrieve the JavaBeans PropertyDescriptors for the given property.
static java.beans.PropertyDescriptor[] getPropertyDescriptors(java.lang.Class<?> clazz)
          Retrieve the JavaBeans PropertyDescriptors of a given class.
static MethodParameter getWriteMethodParameter(java.beans.PropertyDescriptor pd)
          Obtain a new MethodParameter object for the write method of the specified property.
static
<T> T
instantiate(java.lang.Class<T> clazz)
          Convenience method to instantiate a class using its no-arg constructor.
static
<T> T
instantiateClass(java.lang.Class<?> clazz, java.lang.Class<T> assignableTo)
          Instantiate a class using its no-arg constructor and return the new instance as the the specified assignable type.
static
<T> T
instantiateClass(java.lang.Class<T> clazz)
          Instantiate a class using its no-arg constructor.
static
<T> T
instantiateClass(java.lang.reflect.Constructor<T> ctor, java.lang.Object... args)
          Convenience method to instantiate a class using the given constructor.
static boolean isSimpleProperty(java.lang.Class<?> clazz)
          Check if the given type represents a "simple" property: a primitive, a String or other CharSequence, a Number, a Date, a URI, a URL, a Locale, a Class, or a corresponding array.
static boolean isSimpleValueType(java.lang.Class<?> clazz)
          Check if the given type represents a "simple" value type: a primitive, a String or other CharSequence, a Number, a Date, a URI, a URL, a Locale or a Class.
static java.lang.reflect.Method resolveSignature(java.lang.String signature, java.lang.Class<?> clazz)
          Parse a method signature in the form methodName[([arg_list])], where arg_list is an optional, comma-separated list of fully-qualified type names, and attempts to resolve that signature against the supplied Class.
 
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

instantiate

public static <T> T instantiate(java.lang.Class<T> clazz)
                     throws BeanInstantiationException
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.

Parameters:
clazz - class to instantiate
Returns:
the new instance
Throws:
BeanInstantiationException - if the bean cannot be instantiated

instantiateClass

public static <T> T instantiateClass(java.lang.Class<T> clazz)
                          throws BeanInstantiationException
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 (that is, non-public) constructor.

Parameters:
clazz - class to instantiate
Returns:
the new instance
Throws:
BeanInstantiationException - if the bean cannot be instantiated

instantiateClass

public static <T> T instantiateClass(java.lang.Class<?> clazz,
                                     java.lang.Class<T> assignableTo)
                          throws BeanInstantiationException
Instantiate a class using its no-arg constructor and return the new instance as the the specified assignable type.

Useful in cases where the type of the class to instantiate (clazz) is not available, but the type desired (assignableTo) is known.

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 (that is, non-public) constructor.

Parameters:
clazz - class to instantiate
assignableTo - type that clazz must be assignableTo
Returns:
the new instance
Throws:
BeanInstantiationException - if the bean cannot be instantiated

instantiateClass

public static <T> T instantiateClass(java.lang.reflect.Constructor<T> ctor,
                                     java.lang.Object... args)
                          throws BeanInstantiationException
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 (that is, non-public) constructor.

Parameters:
ctor - the constructor to instantiate
args - the constructor arguments to apply
Returns:
the new instance
Throws:
BeanInstantiationException - if the bean cannot be instantiated

findMethod

public static java.lang.reflect.Method findMethod(java.lang.Class<?> clazz,
                                                  java.lang.String methodName,
                                                  java.lang.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 java.lang.reflect.Method findDeclaredMethod(java.lang.Class<?> clazz,
                                                          java.lang.String methodName,
                                                          java.lang.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 java.lang.reflect.Method findMethodWithMinimalParameters(java.lang.Class<?> clazz,
                                                                       java.lang.String methodName)
                                                                throws java.lang.IllegalArgumentException
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 for finding 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
Throws:
java.lang.IllegalArgumentException - if methods of the given name were found but could not be resolved to a unique method with minimal parameters
See Also:
Class.getMethods(), findDeclaredMethodWithMinimalParameters(java.lang.Class, java.lang.String)

findDeclaredMethodWithMinimalParameters

public static java.lang.reflect.Method findDeclaredMethodWithMinimalParameters(java.lang.Class<?> clazz,
                                                                               java.lang.String methodName)
                                                                        throws java.lang.IllegalArgumentException
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
Throws:
java.lang.IllegalArgumentException - if methods of the given name were found but could not be resolved to a unique method with minimal parameters
See Also:
Class.getDeclaredMethods()

findMethodWithMinimalParameters

public static java.lang.reflect.Method findMethodWithMinimalParameters(java.lang.reflect.Method[] methods,
                                                                       java.lang.String methodName)
                                                                throws java.lang.IllegalArgumentException
Find a method with the given method name and minimal parameters (best case: none) in the given list of methods.

Parameters:
methods - the methods to check
methodName - the name of the method to find
Returns:
the Method object, or null if not found
Throws:
java.lang.IllegalArgumentException - if methods of the given name were found but could not be resolved to a unique method with minimal parameters

resolveSignature

public static java.lang.reflect.Method resolveSignature(java.lang.String signature,
                                                        java.lang.Class<?> clazz)
Parse a method signature in the form methodName[([arg_list])], where arg_list is an optional, comma-separated list of fully-qualified type names, and attempts to resolve that signature against the supplied Class.

When not supplying an argument list (methodName) the method whose name matches and has the least number of parameters will be returned. When supplying an argument type list, only the method whose name and argument types match will be returned.

Note then that methodName and methodName() are not resolved in the same way. The signature methodName means the method called methodName with the least number of arguments, whereas methodName() means the method called methodName with exactly 0 arguments.

If no method can be found, then null is returned.

Parameters:
signature - the method signature as String representation
clazz - the class to resolve the method signature against
Returns:
the resolved Method
See Also:
findMethod(java.lang.Class, java.lang.String, java.lang.Class...), findMethodWithMinimalParameters(java.lang.Class, java.lang.String)

getPropertyDescriptors

public static java.beans.PropertyDescriptor[] getPropertyDescriptors(java.lang.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

getPropertyDescriptor

public static java.beans.PropertyDescriptor getPropertyDescriptor(java.lang.Class<?> clazz,
                                                                  java.lang.String propertyName)
                                                           throws BeansException
Retrieve the JavaBeans PropertyDescriptors for the given property.

Parameters:
clazz - the Class to retrieve the PropertyDescriptor for
propertyName - the name of the property
Returns:
the corresponding PropertyDescriptor, or null if none
Throws:
BeansException - if PropertyDescriptor lookup fails

findPropertyForMethod

public static java.beans.PropertyDescriptor findPropertyForMethod(java.lang.reflect.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 lookup fails

findEditorByConvention

public static java.beans.PropertyEditor findEditorByConvention(java.lang.Class<?> targetType)
Find a JavaBeans PropertyEditor following the 'Editor' suffix convention (e.g. "mypackage.MyDomainClass" -> "mypackage.MyDomainClassEditor").

Compatible to the standard JavaBeans convention as implemented by PropertyEditorManager but isolated from the latter's registered default editors for primitive types.

Parameters:
targetType - the type to find an editor for
Returns:
the corresponding editor, or null if none found

findPropertyType

public static java.lang.Class<?> findPropertyType(java.lang.String propertyName,
                                                  java.lang.Class<?>[] beanClasses)
Determine the bean property type for the given property from the given classes/interfaces, if possible.

Parameters:
propertyName - the name of the bean property
beanClasses - the classes to check against
Returns:
the property type, or Object.class as fallback

getWriteMethodParameter

public static MethodParameter getWriteMethodParameter(java.beans.PropertyDescriptor pd)
Obtain a new MethodParameter object for the write method of the specified property.

Parameters:
pd - the PropertyDescriptor for the property
Returns:
a corresponding MethodParameter object

isSimpleProperty

public static boolean isSimpleProperty(java.lang.Class<?> clazz)
Check if the given type represents a "simple" property: a primitive, a String or other CharSequence, a Number, a Date, a URI, a URL, a Locale, a Class, or a corresponding array.

Used to determine properties to check for a "simple" dependency-check.

Parameters:
clazz - the type to check
Returns:
whether the given type represents a "simple" property
See Also:
AbstractBeanDefinition.DEPENDENCY_CHECK_SIMPLE, AbstractAutowireCapableBeanFactory.checkDependencies(java.lang.String, org.springframework.beans.factory.support.AbstractBeanDefinition, java.beans.PropertyDescriptor[], org.springframework.beans.PropertyValues)

isSimpleValueType

public static boolean isSimpleValueType(java.lang.Class<?> clazz)
Check if the given type represents a "simple" value type: a primitive, a String or other CharSequence, a Number, a Date, a URI, a URL, a Locale or a Class.

Parameters:
clazz - the type to check
Returns:
whether the given type represents a "simple" value type

copyProperties

public static void copyProperties(java.lang.Object source,
                                  java.lang.Object target)
                           throws BeansException
Copy the property values of the given source bean into the target bean.

Note: The source and target classes do not have to match or even be derived from each other, as long as the properties match. Any bean properties that the source bean exposes but the target bean does not will silently be ignored.

This is just a convenience method. For more complex transfer needs, consider using a full BeanWrapper.

Parameters:
source - the source bean
target - the target bean
Throws:
BeansException - if the copying failed
See Also:
BeanWrapper

copyProperties

public static void copyProperties(java.lang.Object source,
                                  java.lang.Object target,
                                  java.lang.Class<?> editable)
                           throws BeansException
Copy the property values of the given source bean into the given target bean, only setting properties defined in the given "editable" class (or interface).

Note: The source and target classes do not have to match or even be derived from each other, as long as the properties match. Any bean properties that the source bean exposes but the target bean does not will silently be ignored.

This is just a convenience method. For more complex transfer needs, consider using a full BeanWrapper.

Parameters:
source - the source bean
target - the target bean
editable - the class (or interface) to restrict property setting to
Throws:
BeansException - if the copying failed
See Also:
BeanWrapper

copyProperties

public static void copyProperties(java.lang.Object source,
                                  java.lang.Object target,
                                  java.lang.String[] ignoreProperties)
                           throws BeansException
Copy the property values of the given source bean into the given target bean, ignoring the given "ignoreProperties".

Note: The source and target classes do not have to match or even be derived from each other, as long as the properties match. Any bean properties that the source bean exposes but the target bean does not will silently be ignored.

This is just a convenience method. For more complex transfer needs, consider using a full BeanWrapper.

Parameters:
source - the source bean
target - the target bean
ignoreProperties - array of property names to ignore
Throws:
BeansException - if the copying failed
See Also:
BeanWrapper

Spring Framework