Class BeanToPropertyValueTransformer
- All Implemented Interfaces:
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...
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The top level object in the
peeopleCollectionis an object which represents a person. -
The person object has a
getAddress()method which returns an object which represents a person's address. -
The address object has a
getCity()method which returns an object which represents the city in which a person lives.
- See Also:
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Constructor Summary
ConstructorsConstructorDescriptionBeanToPropertyValueTransformer(String propertyName) Constructs a Transformer which does not ignore nulls.BeanToPropertyValueTransformer(String propertyName, boolean ignoreNull) Constructs a Transformer and sets ignoreNull. -
Method Summary
Modifier and TypeMethodDescriptionReturns the name of the property that will be used in the transformation of the bean.booleanReturns the flag which determines whethernullobjects in the property path will genenerate anIllegalArgumentExceptionor not.Returns the value of the property named in the transformer's constructor for the object provided.
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Constructor Details
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BeanToPropertyValueTransformer
Constructs a Transformer which does not ignore nulls. Constructor which takes the name of the property that will be used in the transformation and assumesignoreNullto befalse.- Parameters:
propertyName- The name of the property that will be used in the transformation.- Throws:
IllegalArgumentException- If thepropertyNameisnullor empty.
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BeanToPropertyValueTransformer
Constructs a Transformer and sets ignoreNull. Constructor which takes the name of the property that will be used in the transformation and a boolean which determines whethernullobjects in the property path will genenerate anIllegalArgumentExceptionor not.- Parameters:
propertyName- The name of the property that will be used in the transformation.ignoreNull- Determines whethernullobjects in the property path will genenerate anIllegalArgumentExceptionor not.- Throws:
IllegalArgumentException- If thepropertyNameisnullor empty.
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Method Details
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getPropertyName
Returns the name of the property that will be used in the transformation of the bean.- Returns:
- The name of the property that will be used in the transformation of the bean.
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isIgnoreNull
Returns the flag which determines whethernullobjects in the property path will genenerate anIllegalArgumentExceptionor not. If set totruethen if any objects in the property path evaluate tonullthen theIllegalArgumentExceptionthrow byPropertyUtilswill be logged but not rethrown andnullwill be returned. If set tofalsethen if any objects in the property path evaluate tonullthen theIllegalArgumentExceptionthrow byPropertyUtilswill be logged and rethrown.- Returns:
- The flag which determines whether
nullobjects in the property path will genenerate anIllegalArgumentExceptionor not.
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transform
Returns the value of the property named in the transformer's constructor for the object provided. If any object in the property path leading up to the target property isnullthen the outcome will be based on the value of theignoreNullattribute. By default,ignoreNullisfalseand would result in anIllegalArgumentExceptionif an object in the property path leading up to the target property isnull.- Specified by:
transformin interfaceorg.apache.commons.collections.Transformer- Parameters:
object- The object to be transformed.- Returns:
- The value of the property named in the transformer's constructor for the object provided.
- Throws:
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 isnullandignoreNullis set tofalse.
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