public class BeanToPropertyValueTransformer extends Object implements org.apache.commons.collections.Transformer
Transformer
that outputs a property value.
An implementation of org.apache.commons.collections.Transformer
that transforms
the object provided by returning the value of a specified property of the object. The
constructor for BeanToPropertyValueTransformer
requires the name of the property
that will be used in the transformation. The property can be a simple, nested, indexed, or
mapped property as defined by org.apache.commons.beanutils.PropertyUtils
. If any
object in the property path specified by propertyName
is null
then the
outcome is based on the value of the ignoreNull
attribute.
A typical usage might look like:
// create the transformer
BeanToPropertyValueTransformer transformer = new BeanToPropertyValueTransformer( "person.address.city" );
// transform the Collection
Collection peoplesCities = CollectionUtils.collect( peopleCollection, transformer );
This would take a Collection
of person objects and return a Collection
of objects which represents the cities in which each person lived. Assuming...
peeopleCollection
is an object which represents a
person.
getAddress()
method which returns an object which
represents a person's address.
getCity()
method which returns an object which
represents the city in which a person lives.
PropertyUtils
,
Transformer
Constructor and Description |
---|
BeanToPropertyValueTransformer(String propertyName)
Constructs a Transformer which does not ignore nulls.
|
BeanToPropertyValueTransformer(String propertyName,
boolean ignoreNull)
Constructs a Transformer and sets ignoreNull.
|
Modifier and Type | Method and Description |
---|---|
String |
getPropertyName()
Returns the name of the property that will be used in the transformation of the bean.
|
boolean |
isIgnoreNull()
Returns the flag which determines whether
null objects in the property path will
genenerate an IllegalArgumentException or not. |
Object |
transform(Object object)
Returns the value of the property named in the transformer's constructor for
the object provided.
|
public BeanToPropertyValueTransformer(String propertyName)
ignoreNull
to be false
.propertyName
- The name of the property that will be used in the transformation.IllegalArgumentException
- If the propertyName
is null
or
empty.public BeanToPropertyValueTransformer(String propertyName, boolean ignoreNull)
null
objects in the property path will
genenerate an IllegalArgumentException
or not.propertyName
- The name of the property that will be used in the transformation.ignoreNull
- Determines whether null
objects in the property path will
genenerate an IllegalArgumentException
or not.IllegalArgumentException
- If the propertyName
is null
or
empty.public Object transform(Object object)
null
then the outcome will be based on the value of the ignoreNull
attribute. By default, ignoreNull
is false
and would result in an
IllegalArgumentException
if an object in the property path leading up to the
target property is null
.transform
in interface org.apache.commons.collections.Transformer
object
- The object to be transformed.IllegalArgumentException
- If an IllegalAccessException, InvocationTargetException, or
NoSuchMethodException is thrown when trying to access the property specified on the object
provided. Or if an object in the property path provided is null
and
ignoreNull
is set to false
.public String getPropertyName()
public boolean isIgnoreNull()
null
objects in the property path will
genenerate an IllegalArgumentException
or not. If set to true
then
if any objects in the property path evaluate to null
then the
IllegalArgumentException
throw by PropertyUtils
will be logged but
not rethrown and null
will be returned. If set to false
then if any
objects in the property path evaluate to null
then the
IllegalArgumentException
throw by PropertyUtils
will be logged and
rethrown.null
objects in the property path will
genenerate an IllegalArgumentException
or not.Copyright © 2000–2016 The Apache Software Foundation. All rights reserved.