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java.lang.Objectorg.apache.commons.beanutils.BeanPropertyValueEqualsPredicate
public class BeanPropertyValueEqualsPredicate
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 )
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...
peeopleCollection
is an object which represents a
person.
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.
- Author:
- Norm Deane
- See Also:
PropertyUtils
,
Predicate
Constructor Summary
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
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 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Constructor Detail
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 Detail
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 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.
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