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 )
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Will create a
Predicate
that will evaluate the target object and returntrue
if the property specified bypropertyName
has a value which is equal to the the value specified bypropertyValue
. Or returnfalse
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'sactiveEmployee
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'spersonId
property.
- Version:
- $Id$
- See Also:
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate boolean
Shouldnull
objects in the property path be ignored?private final org.apache.commons.logging.Log
For logging.private String
The name of the property which will be evaluated when thisPredicate
is executed.private Object
The value that the property specified bypropertyName
will be compared to when thisPredicate
executes. -
Constructor Summary
ConstructorsConstructorDescriptionBeanPropertyValueEqualsPredicate
(String propertyName, Object propertyValue) Constructor which takes the name of the property, its expected value to be used in evaluation, and assumesignoreNull
to 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 whethernull
objects in the property path will genenerate anIllegalArgumentException
or not. -
Method Summary
Modifier and TypeMethodDescriptionboolean
Evaulates the object provided against the criteria specified when thisBeanPropertyValueEqualsPredicate
was constructed.protected boolean
evaluateValue
(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 thisPredicate
is executed.Returns the value that the property specified bypropertyName
will be compared to when thisPredicate
executes.boolean
Returns the flag which determines whethernull
objects in the property path will genenerate anIllegalArgumentException
or not.
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Field Details
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log
private final org.apache.commons.logging.Log logFor logging. -
propertyName
The name of the property which will be evaluated when thisPredicate
is executed. -
propertyValue
The value that the property specified bypropertyName
will be compared to when thisPredicate
executes. -
ignoreNull
private boolean ignoreNullShould
null
objects in the property path be ignored?Determines whether
null
objects in the property path will genenerate anIllegalArgumentException
or not. If set totrue
then if any objects in the property path evaluate tonull
then theIllegalArgumentException
throw byPropertyUtils
will be logged but not rethrown andfalse
will be returned. If set tofalse
then if any objects in the property path evaluate tonull
then theIllegalArgumentException
throw byPropertyUtils
will be logged and rethrown.
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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 assumesignoreNull
to 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 whethernull
objects in the property path will genenerate anIllegalArgumentException
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 whethernull
objects in the property path will genenerate anIllegalArgumentException
or 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 thisBeanPropertyValueEqualsPredicate
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 isnull
then the outcome will be based on the value of theignoreNull
attribute. By default,ignoreNull
isfalse
and would result in anIllegalArgumentException
if an object in the property path leading up to the target property isnull
.- Specified by:
evaluate
in 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 isnull
andignoreNull
is 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 thisPredicate
is executed.- Returns:
- The name of the property which will be evaluated when this
Predicate
is executed.
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getPropertyValue
Returns the value that the property specified bypropertyName
will be compared to when thisPredicate
executes.- Returns:
- The value that the property specified by
propertyName
will be compared to when thisPredicate
executes.
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isIgnoreNull
public boolean isIgnoreNull()Returns the flag which determines whethernull
objects in the property path will genenerate anIllegalArgumentException
or not. If set totrue
then if any objects in the property path evaluate tonull
then theIllegalArgumentException
throw byPropertyUtils
will be logged but not rethrown andfalse
will be returned. If set tofalse
then if any objects in the property path evaluate tonull
then theIllegalArgumentException
throw byPropertyUtils
will be logged and rethrown.- Returns:
- The flag which determines whether
null
objects in the property path will genenerate anIllegalArgumentException
or not.
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