Package org.apache.commons.beanutils2

Class BeanToPropertyValueTransformer<T,R>

java.lang.Object
org.apache.commons.beanutils2.BeanToPropertyValueTransformer<T,R>
Type Parameters:
T - the type of the input to the function
R - the type of the result of the function
All Implemented Interfaces:
Function<T,R>
public class BeanToPropertyValueTransformer<T,R> extends Object implements Function<T,R>

Transformer that outputs a property value.

An implementation of Function 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.beanutils2.PropertyUtils. If any object in the property path specified by propertyName</code> is <code>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</code> of person objects and return a <code>Collection of objects which represents the cities in which each person lived. Assuming...

  • The top level object in the peopleCollection is 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:

  • Constructor Summary

    Constructors
    Constructor
    Description
    BeanToPropertyValueTransformer(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 Type
    Method
    Description
    R
    apply(T object)
    Returns the value of the property named in the transformer's constructor for the object provided.
    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 generate an IllegalArgumentException</code> or not. If set to <code>true then if any objects in the property path evaluate to null then the IllegalArgumentException</code> throw by <code>PropertyUtils will be logged but not re-thrown and null</code> will be returned. If set to <code>false then if any objects in the property path evaluate to null then the IllegalArgumentException</code> throw by <code>PropertyUtils will be logged and re-thrown.

    Methods inherited from class java.lang.Object

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

    Methods inherited from interface java.util.function.Function

    andThen, compose

  • Constructor Details

    • BeanToPropertyValueTransformer

      public BeanToPropertyValueTransformer(String propertyName)
      Constructs a Transformer which does not ignore nulls. Constructor which takes the name of the property that will be used in the transformation and assumes ignoreNull</code> to be <code>false.
      Parameters:
      propertyName - The name of the property that will be used in the transformation.
      Throws:
      IllegalArgumentException - If the propertyName</code> is <code>null or empty.

    • BeanToPropertyValueTransformer

      public BeanToPropertyValueTransformer(String propertyName, boolean ignoreNull)
      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 whether null objects in the property path will generate an IllegalArgumentException or not.
      Parameters:
      propertyName - The name of the property that will be used in the transformation.
      ignoreNull - Determines whether null objects in the property path will generate an IllegalArgumentException or not.
      Throws:
      IllegalArgumentException - If the propertyName</code> is <code>null or empty.

  • Method Details

    • apply

      public R apply(T object)
      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 is null</code> then the outcome will be based on the value of the <code>ignoreNull attribute. By default, ignoreNull</code> is <code>false and would result in an IllegalArgumentException if an object in the property path leading up to the target property is null. @param object The object to be transformed. @return The value of the property named in the transformer's constructor for the object provided.
      Specified by:
      apply in interface Function<T,R>
      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 is null and ignoreNull</code> is set to <code>false.

    • getPropertyName

      public String 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.

    • isIgnoreNull

      public boolean isIgnoreNull()
      Returns the flag which determines whether null objects in the property path will generate an IllegalArgumentException</code> or not. If set to <code>true then if any objects in the property path evaluate to null then the IllegalArgumentException</code> throw by <code>PropertyUtils will be logged but not re-thrown and null</code> will be returned. If set to <code>false then if any objects in the property path evaluate to null then the IllegalArgumentException</code> throw by <code>PropertyUtils will be logged and re-thrown.
      Returns:
      The flag which determines whether null objects in the property path will generate an IllegalArgumentException or not.