Class BeanPropertyValueEqualsPredicate
- All Implemented Interfaces:
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.
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public BeanPropertyValueEqualsPredicate(String propertyName, Object propertyValue) -
Will create a
Predicatethat will evaluate the target object and returntrueif the property specified bypropertyNamehas a value which is equal to the the value specified bypropertyValue. Or returnfalseotherwise.
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...
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The top level object in the
peeopleCollectionis an object which represents a person. -
The person object has a
getActiveEmployee()method which returns the boolean value for the object'sactiveEmployeeproperty.
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...
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The top level object in the
peeopleCollectionis an object which represents a person. -
The person object has a
getPersonId()method which returns the value for the object'spersonIdproperty.
- See Also:
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Constructor Summary
ConstructorsConstructorDescriptionBeanPropertyValueEqualsPredicate(String propertyName, Object propertyValue) Constructor which takes the name of the property, its expected value to be used in evaluation, and assumesignoreNullto befalse.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 whethernullobjects in the property path will genenerate anIllegalArgumentExceptionor not. -
Method Summary
Modifier and TypeMethodDescriptionbooleanEvaulates the object provided against the criteria specified when thisBeanPropertyValueEqualsPredicatewas constructed.protected booleanevaluateValue(Object expected, Object actual) Utility method which evaluates whether the actual property value equals the expected property value.Returns the name of the property which will be evaluated when thisPredicateis executed.Returns the value that the property specified bypropertyNamewill be compared to when thisPredicateexecutes.booleanReturns the flag which determines whethernullobjects in the property path will genenerate anIllegalArgumentExceptionor not.
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Constructor Details
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BeanPropertyValueEqualsPredicate
Constructor which takes the name of the property, its expected value to be used in evaluation, and assumesignoreNullto befalse.- 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.
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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 whethernullobjects in the property path will genenerate anIllegalArgumentExceptionor 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 whethernullobjects in the property path will genenerate anIllegalArgumentExceptionor not.- Throws:
IllegalArgumentException- If the property name provided is null or empty.
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Method Details
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evaluate
Evaulates the object provided against the criteria specified when thisBeanPropertyValueEqualsPredicatewas 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 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:
evaluatein interfaceorg.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 isnullandignoreNullis set tofalse.
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evaluateValue
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.
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getPropertyName
Returns the name of the property which will be evaluated when thisPredicateis executed.- Returns:
- The name of the property which will be evaluated when this
Predicateis executed.
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getPropertyValue
Returns the value that the property specified bypropertyNamewill be compared to when thisPredicateexecutes.- Returns:
- The value that the property specified by
propertyNamewill be compared to when thisPredicateexecutes.
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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 andfalsewill 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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