org.apache.commons.beanutils

Class BeanUtilsBean

java.lang.Object

org.apache.commons.beanutils.BeanUtilsBean

Direct Known Subclasses:

BeanUtilsBean2, LocaleBeanUtilsBean

public class BeanUtilsBean
extends Object

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.

Since:

1.7

Version:

$Id$

See Also:

BeanUtils

Constructor Summary

Constructors

Constructor and Description
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.

Method Summary

Modifier and Type	Method and Description
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.
protected Object	convert(Object value, Class<?> type) Convert the value to an object of the specified class (if possible).
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<String,String>	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) Return the value of the specified indexed property of the specified bean, as a String.
String	getMappedProperty(Object bean, String name, String key) Return the value of the specified mapped 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<String,? extends Object> 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.

Methods inherited from class java.lang.Object

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

Constructor Detail

BeanUtilsBean

public BeanUtilsBean()

Constructs an instance using new property and conversion instances.

BeanUtilsBean

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

Since:

1.8.0

BeanUtilsBean

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

Method Detail

getInstance

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

setInstance

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

cloneBean

public Object cloneBean(Object bean)
                 throws IllegalAccessException,
                        InstantiationException,
                        InvocationTargetException,
                        NoSuchMethodException

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

copyProperties

public void copyProperties(Object dest,
                           Object orig)
                    throws IllegalAccessException,
                           InvocationTargetException

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

copyProperty

public void copyProperty(Object bean,
                         String name,
                         Object value)
                  throws IllegalAccessException,
                         InvocationTargetException

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

describe

public Map<String,String> describe(Object bean)
                            throws IllegalAccessException,
                                   InvocationTargetException,
                                   NoSuchMethodException

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

getArrayProperty

public String[] getArrayProperty(Object bean,
                                 String name)
                          throws IllegalAccessException,
                                 InvocationTargetException,
                                 NoSuchMethodException

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

getIndexedProperty

public String getIndexedProperty(Object bean,
                                 String name)
                          throws IllegalAccessException,
                                 InvocationTargetException,
                                 NoSuchMethodException

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

getIndexedProperty

public String getIndexedProperty(Object bean,
                                 String name,
                                 int index)
                          throws IllegalAccessException,
                                 InvocationTargetException,
                                 NoSuchMethodException

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

getMappedProperty

public String getMappedProperty(Object bean,
                                String name)
                         throws IllegalAccessException,
                                InvocationTargetException,
                                NoSuchMethodException

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

getMappedProperty

public String getMappedProperty(Object bean,
                                String name,
                                String key)
                         throws IllegalAccessException,
                                InvocationTargetException,
                                NoSuchMethodException

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

getNestedProperty

public String getNestedProperty(Object bean,
                                String name)
                         throws IllegalAccessException,
                                InvocationTargetException,
                                NoSuchMethodException

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

getProperty

public String getProperty(Object bean,
                          String name)
                   throws IllegalAccessException,
                          InvocationTargetException,
                          NoSuchMethodException

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

getSimpleProperty

public String getSimpleProperty(Object bean,
                                String name)
                         throws IllegalAccessException,
                                InvocationTargetException,
                                NoSuchMethodException

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

populate

public void populate(Object bean,
                     Map<String,? extends Object> properties)
              throws IllegalAccessException,
                     InvocationTargetException

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

setProperty

public void setProperty(Object bean,
                        String name,
                        Object value)
                 throws IllegalAccessException,
                        InvocationTargetException

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

getConvertUtils

public ConvertUtilsBean getConvertUtils()

Gets the ConvertUtilsBean instance used to perform the conversions.

Returns:

The ConvertUtils bean instance

getPropertyUtils

public PropertyUtilsBean getPropertyUtils()

Gets the PropertyUtilsBean instance used to access properties.

Returns:

The ConvertUtils bean instance

initCause

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.

Since:

1.8.0

convert

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

Since:

1.8.0