public class

BeanUtilsBean

extends Object
java.lang.Object
   ↳ org.apache.commons.beanutils.BeanUtilsBean
Known Direct Subclasses

Class Overview

JavaBean property population methods.

This class provides implementations for the utility methods in BeanUtils. Different instances can be used to isolate caches between classloaders and to vary the value converters registered.

See Also

Summary

Public Constructors
BeanUtilsBean()

Constructs an instance using new property and conversion instances.

BeanUtilsBean(ConvertUtilsBean convertUtilsBean)

Constructs an instance using given conversion instances and new PropertyUtilsBean instance.

BeanUtilsBean(ConvertUtilsBean convertUtilsBean, PropertyUtilsBean propertyUtilsBean)

Constructs an instance using given property and conversion instances.

Public Methods
Object cloneBean(Object bean)

Clone a bean based on the available property getters and setters, even if the bean class itself does not implement Cloneable.

void copyProperties(Object dest, Object orig)

Copy property values from the origin bean to the destination bean for all cases where the property names are the same.

void copyProperty(Object bean, String name, Object value)

Copy the specified property value to the specified destination bean, performing any type conversion that is required.

Map describe(Object bean)

Return the entire set of properties for which the specified bean provides a read method.

String[] getArrayProperty(Object bean, String name)
Return the value of the specified array property of the specified bean, as a String array.
ConvertUtilsBean getConvertUtils()
Gets the ConvertUtilsBean instance used to perform the conversions.
String getIndexedProperty(Object bean, String name)
Return the value of the specified indexed property of the specified bean, as a String.
String getIndexedProperty(Object bean, String name, int index)
Return the value of the specified indexed property of the specified bean, as a String.
static BeanUtilsBean getInstance()
Gets the instance which provides the functionality for BeanUtils.
String getMappedProperty(Object bean, String name, String key)
Return the value of the specified mapped property of the specified bean, as a String.
String getMappedProperty(Object bean, String name)
Return the value of the specified indexed property of the specified bean, as a String.
String getNestedProperty(Object bean, String name)
Return the value of the (possibly nested) property of the specified name, for the specified bean, as a String.
String getProperty(Object bean, String name)
Return the value of the specified property of the specified bean, no matter which property reference format is used, as a String.
PropertyUtilsBean getPropertyUtils()
Gets the PropertyUtilsBean instance used to access properties.
String getSimpleProperty(Object bean, String name)
Return the value of the specified simple property of the specified bean, converted to a String.
boolean initCause(Throwable throwable, Throwable cause)
If we're running on JDK 1.4 or later, initialize the cause for the given throwable.
void populate(Object bean, Map properties)

Populate the JavaBeans properties of the specified bean, based on the specified name/value pairs.

static void setInstance(BeanUtilsBean newInstance)
Sets the instance which provides the functionality for BeanUtils.
void setProperty(Object bean, String name, Object value)

Set the specified property value, performing type conversions as required to conform to the type of the destination property.

Protected Methods
Object convert(Object value, Class type)

Convert the value to an object of the specified class (if possible).

[Expand]
Inherited Methods
From class java.lang.Object

Public Constructors

public BeanUtilsBean ()

Constructs an instance using new property and conversion instances.

public BeanUtilsBean (ConvertUtilsBean convertUtilsBean)

Constructs an instance using given conversion instances and new PropertyUtilsBean instance.

Parameters
convertUtilsBean use this ConvertUtilsBean to perform conversions from one object to another

public BeanUtilsBean (ConvertUtilsBean convertUtilsBean, PropertyUtilsBean propertyUtilsBean)

Constructs an instance using given property and conversion instances.

Parameters
convertUtilsBean use this ConvertUtilsBean to perform conversions from one object to another
propertyUtilsBean use this PropertyUtilsBean to access properties

Public Methods

public Object cloneBean (Object bean)

Clone a bean based on the available property getters and setters, even if the bean class itself does not implement Cloneable.

Note: this method creates a shallow clone. In other words, any objects referred to by the bean are shared with the clone rather than being cloned in turn.

Parameters
bean Bean to be cloned
Returns
  • the cloned bean
Throws
IllegalAccessException if the caller does not have access to the property accessor method
InstantiationException if a new instance of the bean's class cannot be instantiated
InvocationTargetException if the property accessor method throws an exception
NoSuchMethodException if an accessor method for this property cannot be found

public void copyProperties (Object dest, Object orig)

Copy property values from the origin bean to the destination bean for all cases where the property names are the same. For each property, a conversion is attempted as necessary. All combinations of standard JavaBeans and DynaBeans as origin and destination are supported. Properties that exist in the origin bean, but do not exist in the destination bean (or are read-only in the destination bean) are silently ignored.

If the origin "bean" is actually a Map, it is assumed to contain String-valued simple property names as the keys, pointing at the corresponding property values that will be converted (if necessary) and set in the destination bean. Note that this method is intended to perform a "shallow copy" of the properties and so complex properties (for example, nested ones) will not be copied.

This method differs from populate(), which was primarily designed for populating JavaBeans from the map of request parameters retrieved on an HTTP request, is that no scalar->indexed or indexed->scalar manipulations are performed. If the origin property is indexed, the destination property must be also.

If you know that no type conversions are required, the copyProperties() method in PropertyUtils will execute faster than this method.

FIXME - Indexed and mapped properties that do not have getter and setter methods for the underlying array or Map are not copied by this method.

Parameters
dest Destination bean whose properties are modified
orig Origin bean whose properties are retrieved
Throws
IllegalAccessException if the caller does not have access to the property accessor method
IllegalArgumentException if the dest or orig argument is null or if the dest property type is different from the source type and the relevant converter has not been registered.
InvocationTargetException if the property accessor method throws an exception

public void copyProperty (Object bean, String name, Object value)

Copy the specified property value to the specified destination bean, performing any type conversion that is required. If the specified bean does not have a property of the specified name, or the property is read only on the destination bean, return without doing anything. If you have custom destination property types, register Converters for them by calling the register() method of ConvertUtils.

IMPLEMENTATION RESTRICTIONS:

  • Does not support destination properties that are indexed, but only an indexed setter (as opposed to an array setter) is available.
  • Does not support destination properties that are mapped, but only a keyed setter (as opposed to a Map setter) is available.
  • The desired property type of a mapped setter cannot be determined (since Maps support any data type), so no conversion will be performed.

Parameters
bean Bean on which setting is to be performed
name Property name (can be nested/indexed/mapped/combo)
value Value to be set
Throws
IllegalAccessException if the caller does not have access to the property accessor method
InvocationTargetException if the property accessor method throws an exception

public Map describe (Object bean)

Return the entire set of properties for which the specified bean provides a read method. This map contains the to String converted property values for all properties for which a read method is provided (i.e. where the getReadMethod() returns non-null).

This map can be fed back to a call to BeanUtils.populate() to reconsitute the same set of properties, modulo differences for read-only and write-only properties, but only if there are no indexed properties.

Warning: if any of the bean property implementations contain (directly or indirectly) a call to this method then a stack overflow may result. For example: 

 class MyBean
 {
    public Map getParameterMap()
    {
         BeanUtils.describe(this);
    }
 }
will result in an infinite regression when getParametersMap is called. It is recommended that such methods are given alternative names (for example, parametersMap).

Parameters
bean Bean whose properties are to be extracted
Returns
  • Map of property descriptors
Throws
IllegalAccessException if the caller does not have access to the property accessor method
InvocationTargetException if the property accessor method throws an exception
NoSuchMethodException if an accessor method for this property cannot be found

public String[] getArrayProperty (Object bean, String name)

Return the value of the specified array property of the specified bean, as a String array.

Parameters
bean Bean whose property is to be extracted
name Name of the property to be extracted
Returns
  • The array property value
Throws
IllegalAccessException if the caller does not have access to the property accessor method
InvocationTargetException if the property accessor method throws an exception
NoSuchMethodException if an accessor method for this property cannot be found

public ConvertUtilsBean getConvertUtils ()

Gets the ConvertUtilsBean instance used to perform the conversions.

Returns
  • The ConvertUtils bean instance

public String getIndexedProperty (Object bean, String name)

Return the value of the specified indexed property of the specified bean, as a String. The zero-relative index of the required value must be included (in square brackets) as a suffix to the property name, or IllegalArgumentException will be thrown.

Parameters
bean Bean whose property is to be extracted
name propertyname[index] of the property value to be extracted
Returns
  • The indexed property's value, converted to a String
Throws
IllegalAccessException if the caller does not have access to the property accessor method
InvocationTargetException if the property accessor method throws an exception
NoSuchMethodException if an accessor method for this property cannot be found

public String getIndexedProperty (Object bean, String name, int index)

Return the value of the specified indexed property of the specified bean, as a String. The index is specified as a method parameter and must *not* be included in the property name expression

Parameters
bean Bean whose property is to be extracted
name Simple property name of the property value to be extracted
index Index of the property value to be extracted
Returns
  • The indexed property's value, converted to a String
Throws
IllegalAccessException if the caller does not have access to the property accessor method
InvocationTargetException if the property accessor method throws an exception
NoSuchMethodException if an accessor method for this property cannot be found

public static BeanUtilsBean getInstance ()

Gets the instance which provides the functionality for BeanUtils. This is a pseudo-singleton - an single instance is provided per (thread) context classloader. This mechanism provides isolation for web apps deployed in the same container.

Returns
  • The (pseudo-singleton) BeanUtils bean instance

public String getMappedProperty (Object bean, String name, String key)

Return the value of the specified mapped property of the specified bean, as a String. The key is specified as a method parameter and must *not* be included in the property name expression

Parameters
bean Bean whose property is to be extracted
name Simple property name of the property value to be extracted
key Lookup key of the property value to be extracted
Returns
  • The mapped property's value, converted to a String
Throws
IllegalAccessException if the caller does not have access to the property accessor method
InvocationTargetException if the property accessor method throws an exception
NoSuchMethodException if an accessor method for this property cannot be found

public String getMappedProperty (Object bean, String name)

Return the value of the specified indexed property of the specified bean, as a String. The String-valued key of the required value must be included (in parentheses) as a suffix to the property name, or IllegalArgumentException will be thrown.

Parameters
bean Bean whose property is to be extracted
name propertyname(index) of the property value to be extracted
Returns
  • The mapped property's value, converted to a String
Throws
IllegalAccessException if the caller does not have access to the property accessor method
InvocationTargetException if the property accessor method throws an exception
NoSuchMethodException if an accessor method for this property cannot be found

public String getNestedProperty (Object bean, String name)

Return the value of the (possibly nested) property of the specified name, for the specified bean, as a String.

Parameters
bean Bean whose property is to be extracted
name Possibly nested name of the property to be extracted
Returns
  • The nested property's value, converted to a String
Throws
IllegalAccessException if the caller does not have access to the property accessor method
IllegalArgumentException if a nested reference to a property returns null
InvocationTargetException if the property accessor method throws an exception
NoSuchMethodException if an accessor method for this property cannot be found

public String getProperty (Object bean, String name)

Return the value of the specified property of the specified bean, no matter which property reference format is used, as a String.

Parameters
bean Bean whose property is to be extracted
name Possibly indexed and/or nested name of the property to be extracted
Returns
  • The property's value, converted to a String
Throws
IllegalAccessException if the caller does not have access to the property accessor method
InvocationTargetException if the property accessor method throws an exception
NoSuchMethodException if an accessor method for this property cannot be found

public PropertyUtilsBean getPropertyUtils ()

Gets the PropertyUtilsBean instance used to access properties.

Returns
  • The ConvertUtils bean instance

public String getSimpleProperty (Object bean, String name)

Return the value of the specified simple property of the specified bean, converted to a String.

Parameters
bean Bean whose property is to be extracted
name Name of the property to be extracted
Returns
  • The property's value, converted to a String
Throws
IllegalAccessException if the caller does not have access to the property accessor method
InvocationTargetException if the property accessor method throws an exception
NoSuchMethodException if an accessor method for this property cannot be found

public boolean initCause (Throwable throwable, Throwable cause)

If we're running on JDK 1.4 or later, initialize the cause for the given throwable.

Parameters
throwable The throwable.
cause The cause of the throwable.
Returns
  • true if the cause was initialized, otherwise false.

public void populate (Object bean, Map properties)

Populate the JavaBeans properties of the specified bean, based on the specified name/value pairs. This method uses Java reflection APIs to identify corresponding "property setter" method names, and deals with setter arguments of type String, boolean, int, long, float, and double. In addition, array setters for these types (or the corresponding primitive types) can also be identified.

The particular setter method to be called for each property is determined using the usual JavaBeans introspection mechanisms. Thus, you may identify custom setter methods using a BeanInfo class that is associated with the class of the bean itself. If no such BeanInfo class is available, the standard method name conversion ("set" plus the capitalized name of the property in question) is used.

NOTE: It is contrary to the JavaBeans Specification to have more than one setter method (with different argument signatures) for the same property.

WARNING - The logic of this method is customized for extracting String-based request parameters from an HTTP request. It is probably not what you want for general property copying with type conversion. For that purpose, check out the copyProperties() method instead.

Parameters
bean JavaBean whose properties are being populated
properties Map keyed by property name, with the corresponding (String or String[]) value(s) to be set
Throws
IllegalAccessException if the caller does not have access to the property accessor method
InvocationTargetException if the property accessor method throws an exception

public static void setInstance (BeanUtilsBean newInstance)

Sets the instance which provides the functionality for BeanUtils. This is a pseudo-singleton - an single instance is provided per (thread) context classloader. This mechanism provides isolation for web apps deployed in the same container.

Parameters
newInstance The (pseudo-singleton) BeanUtils bean instance

public void setProperty (Object bean, String name, Object value)

Set the specified property value, performing type conversions as required to conform to the type of the destination property.

If the property is read only then the method returns without throwing an exception.

If null is passed into a property expecting a primitive value, then this will be converted as if it were a null string.

WARNING - The logic of this method is customized to meet the needs of populate(), and is probably not what you want for general property copying with type conversion. For that purpose, check out the copyProperty() method instead.

WARNING - PLEASE do not modify the behavior of this method without consulting with the Struts developer community. There are some subtleties to its functionality that are not documented in the Javadoc description above, yet are vital to the way that Struts utilizes this method.

Parameters
bean Bean on which setting is to be performed
name Property name (can be nested/indexed/mapped/combo)
value Value to be set
Throws
IllegalAccessException if the caller does not have access to the property accessor method
InvocationTargetException if the property accessor method throws an exception

Protected Methods

protected Object convert (Object value, Class type)

Convert the value to an object of the specified class (if possible).

Parameters
value Value to be converted (may be null)
type Class of the value to be converted to
Returns
  • The converted value
Throws
ConversionException if thrown by an underlying Converter