Package org.apache.commons.beanutils2

Class BeanPropertyValueEqualsPredicate<T,V>

java.lang.Object
org.apache.commons.beanutils2.BeanPropertyValueEqualsPredicate<T,V>
Type Parameters:
T - The type of the input to the predicate.
V - The property value type.
All Implemented Interfaces:
Predicate<T>
public class BeanPropertyValueEqualsPredicate<T,V> extends Object implements Predicate<T>

Predicate that evaluates a property value against a specified value.

An implementation of 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</code> if the property specified by <code>propertyName has a value which is equal to 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.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 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</code> property is <code>false. Assuming...

  • The top level object in the peopleCollection 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</code> property value equals <code>456-12-1234. Assuming...

  • The top level object in the peopleCollection 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:

  • Constructor Summary

    Constructors
    Constructor
    Description
    BeanPropertyValueEqualsPredicate(String propertyName, V propertyValue)
    Constructor which takes the name of the property, its expected value to be used in evaluation, and assumes ignoreNull</code> to be <code>false.
    BeanPropertyValueEqualsPredicate(String propertyName, V 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 generate an IllegalArgumentException or not.

  • Method Summary

    Modifier and Type
    Method
    Description
    protected boolean
    evaluateValue(V 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.
    V
    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 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 false</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.
    boolean
    test(T object)
    Evaluates the object provided against the criteria specified when this BeanPropertyValueEqualsPredicate was constructed.

    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.Predicate

    and, negate, or

  • Constructor Details

    • BeanPropertyValueEqualsPredicate

      public BeanPropertyValueEqualsPredicate(String propertyName, V propertyValue)
      Constructor which takes the name of the property, its expected value to be used in evaluation, and assumes ignoreNull</code> to be <code>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, V 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 generate 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 generate an IllegalArgumentException or not.
      Throws:
      IllegalArgumentException - If the property name provided is null or empty.

  • Method Details

    • evaluateValue

      protected boolean evaluateValue(V 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 V 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 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 false</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.

    • test

      public boolean test(T object)
      Evaluates 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</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 evaluated. @return True if the object provided meets all the criteria for this Predicate; false otherwise.
      Specified by:
      test in interface Predicate<T>
      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.