Class BeanPropertyValueEqualsPredicate

java.lang.Object
org.apache.commons.beanutils.BeanPropertyValueEqualsPredicate
All Implemented Interfaces:
org.apache.commons.collections.Predicate
public class BeanPropertyValueEqualsPredicate extends Object implements org.apache.commons.collections.Predicate

Predicate that evaluates a property value against a specified value.

An implementation of org.apache.commons.collections.Predicate that evaluates a property value on the object provided against a specified value and returns true if equal; false otherwise. The BeanPropertyValueEqualsPredicate constructor takes two parameters which determine what property will be evaluated on the target object and what its expected value should be.

public BeanPropertyValueEqualsPredicate(String propertyName, Object propertyValue)
Will create a Predicate that will evaluate the target object and return true if the property specified by propertyName has a value which is equal to the the value specified by propertyValue. Or return false otherwise.

Note: Property names 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 closure
BeanPropertyValueEqualsPredicate predicate =
   new BeanPropertyValueEqualsPredicate( "activeEmployee", Boolean.FALSE );

// filter the Collection
CollectionUtils.filter( peopleCollection, predicate );

This would take a Collection of person objects and filter out any people whose activeEmployee property is false. Assuming...

  • The top level object in the peeopleCollection is an object which represents a person.
  • The person object has a getActiveEmployee() method which returns the boolean value for the object's activeEmployee property.

Another typical usage might look like: 

// create the closure
BeanPropertyValueEqualsPredicate predicate =
   new BeanPropertyValueEqualsPredicate( "personId", "456-12-1234" );

// search the Collection
CollectionUtils.find( peopleCollection, predicate );

This would search a Collection of person objects and return the first object whose

personId property value equals 456-12-1234. Assuming...
  • The top level object in the peeopleCollection is an object which represents a person.
  • The person object has a getPersonId() method which returns the value for the object's personId property.
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private final boolean
    ignoreNull
    Should null objects in the property path be ignored?
    private final org.apache.commons.logging.Log
    log
    For logging.
    private final String
    propertyName
    The name of the property which will be evaluated when this Predicate is executed.
    private final Object
    propertyValue
    The value that the property specified by propertyName will be compared to when this Predicate executes.

  • Constructor Summary

    Constructors
    Constructor
    Description
    BeanPropertyValueEqualsPredicate(String propertyName, Object propertyValue)
    Constructor which takes the name of the property, its expected value to be used in evaluation, and assumes ignoreNull to be false.
    BeanPropertyValueEqualsPredicate(String propertyName, Object propertyValue, boolean ignoreNull)
    Constructor which takes the name of the property, its expected value to be used in evaluation, and a boolean which determines whether null objects in the property path will genenerate an IllegalArgumentException or not.

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    evaluate(Object object)
    Evaulates the object provided against the criteria specified when this BeanPropertyValueEqualsPredicate was constructed.
    protected boolean
    evaluateValue(Object expected, Object actual)
    Utility method which evaluates whether the actual property value equals the expected property value.
    String
    getPropertyName()
    Returns the name of the property which will be evaluated when this Predicate is executed.
    Object
    getPropertyValue()
    Returns the value that the property specified by propertyName will be compared to when this Predicate executes.
    boolean
    isIgnoreNull()
    Returns the flag which determines whether null objects in the property path will genenerate an IllegalArgumentException or not.

    Methods inherited from class Object

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

  • Field Details

    • log

      private final org.apache.commons.logging.Log log
      For logging.

    • propertyName

      private final String propertyName
      The name of the property which will be evaluated when this Predicate is executed.

    • propertyValue

      private final Object propertyValue
      The value that the property specified by propertyName will be compared to when this Predicate executes.

    • ignoreNull

      private final boolean ignoreNull

      Should null objects in the property path be ignored?

      Determines whether 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 false 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.

  • Constructor Details

    • BeanPropertyValueEqualsPredicate

      public BeanPropertyValueEqualsPredicate(String propertyName, Object propertyValue)
      Constructor which takes the name of the property, its expected value to be used in evaluation, and assumes ignoreNull to be false.
      Parameters:
      propertyName - The name of the property that will be evaluated against the expected value.
      propertyValue - The value to use in object evaluation.
      Throws:
      IllegalArgumentException - If the property name provided is null or empty.

    • BeanPropertyValueEqualsPredicate

      public BeanPropertyValueEqualsPredicate(String propertyName, Object propertyValue, boolean ignoreNull)
      Constructor which takes the name of the property, its expected value to be used in evaluation, and a boolean which determines whether null objects in the property path will genenerate an IllegalArgumentException or not.
      Parameters:
      propertyName - The name of the property that will be evaluated against the expected value.
      propertyValue - The value to use in object evaluation.
      ignoreNull - Determines whether null objects in the property path will genenerate an IllegalArgumentException or not.
      Throws:
      IllegalArgumentException - If the property name provided is null or empty.

  • Method Details

    • evaluate

      public boolean evaluate(Object object)
      Evaulates the object provided against the criteria specified when this BeanPropertyValueEqualsPredicate was constructed. Equality is based on either reference or logical equality as defined by the property object's equals method. If any object in the property path leading up to the target property is 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.
      Specified by:
      evaluate in interface org.apache.commons.collections.Predicate
      Parameters:
      object - The object to be evaluated.
      Returns:
      True if the object provided meets all the criteria for this Predicate; false otherwise.
      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 is set to false.

    • evaluateValue

      protected boolean evaluateValue(Object expected, Object actual)
      Utility method which evaluates whether the actual property value equals the expected property value.
      Parameters:
      expected - The expected value.
      actual - The actual value.
      Returns:
      True if they are equal; false otherwise.

    • getPropertyName

      public String getPropertyName()
      Returns the name of the property which will be evaluated when this Predicate is executed.
      Returns:
      The name of the property which will be evaluated when this Predicate is executed.

    • getPropertyValue

      public Object getPropertyValue()
      Returns the value that the property specified by propertyName will be compared to when this Predicate executes.
      Returns:
      The value that the property specified by propertyName will be compared to when this Predicate executes.

    • isIgnoreNull

      public boolean isIgnoreNull()
      Returns the flag which determines whether 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 false 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.
      Returns:
      The flag which determines whether null objects in the property path will genenerate an IllegalArgumentException or not.