Package org.apache.commons.collections.functors

package org.apache.commons.collections.functors

This package contains implementations of the Closure, Predicate, Transformer and Factory interfaces. These provide simple callbacks for processing with collections.

WARNING: from v3.2.2 onwards this several classes in this package will throw an UnsupportedOperationException when trying to serialize or de-serialize an instance to prevent potential remote code execution exploits.

Classes considered to be unsafe are:

  • CloneTransformer
  • ForClosure
  • InstantiateFactory
  • InstantiateTransformer
  • InvokerTransformer
  • PrototypeFactory$PrototypeCloneFactory
  • PrototypeFactory$PrototypeSerializationFactory
  • WhileClosure

In order to re-enable serialization support for these unsafe classes, the following system property can be used (via -Dproperty=true): 

org.apache.commons.collections.enableUnsafeSerialization

Be warned though that enabling serialization support for these unsafe classes makes your application vulnerable to known exploits and you must ensure that your application does not de-serialize objects from untrusted sources.

  • Class
    Description
    AllPredicate
    Predicate implementation that returns true if all the predicates return true.
    AndPredicate
    Predicate implementation that returns true if both the predicates return true.
    AnyPredicate
    Predicate implementation that returns true if any of the predicates return true.
    ChainedClosure
    Closure implementation that chains the specified closures together.
    ChainedTransformer
    Transformer implementation that chains the specified transformers together.
    CloneTransformer
    Transformer implementation that returns a clone of the input object.
    ClosureTransformer
    Transformer implementation that calls a Closure using the input object and then returns the input.
    ConstantFactory
    Factory implementation that returns the same constant each time.
    ConstantTransformer
    Transformer implementation that returns the same constant each time.
    EqualPredicate
    Predicate implementation that returns true if the input is the same object as the one stored in this predicate by equals.
    ExceptionClosure
    Closure implementation that always throws an exception.
    ExceptionFactory
    Factory implementation that always throws an exception.
    ExceptionPredicate
    Predicate implementation that always throws an exception.
    ExceptionTransformer
    Transformer implementation that always throws an exception.
    FactoryTransformer
    Transformer implementation that calls a Factory and returns the result.
    FalsePredicate
    Predicate implementation that always returns false.
    ForClosure
    Closure implementation that calls another closure n times, like a for loop.
    IdentityPredicate
    Predicate implementation that returns true if the input is the same object as the one stored in this predicate.
    IfClosure
    Closure implementation acts as an if statement calling one or other closure based on a predicate.
    InstanceofPredicate
    Predicate implementation that returns true if the input is an instanceof the type stored in this predicate.
    InstantiateFactory
    Factory implementation that creates a new object instance by reflection.
    InstantiateTransformer
    Transformer implementation that creates a new object instance by reflection.
    InvokerTransformer
    Transformer implementation that creates a new object instance by reflection.
    MapTransformer
    Transformer implementation that returns the value held in a specified map using the input parameter as a key.
    NonePredicate
    Predicate implementation that returns true if none of the predicates return true.
    NOPClosure
    Closure implementation that does nothing.
    NOPTransformer
    Transformer implementation that does nothing.
    NotNullPredicate
    Predicate implementation that returns true if the input is not null.
    NotPredicate
    Predicate implementation that returns the opposite of the decorated predicate.
    NullIsExceptionPredicate
    Predicate implementation that throws an exception if the input is null.
    NullIsFalsePredicate
    Predicate implementation that returns false if the input is null.
    NullIsTruePredicate
    Predicate implementation that returns true if the input is null.
    NullPredicate
    Predicate implementation that returns true if the input is null.
    OnePredicate
    Predicate implementation that returns true if only one of the predicates return true.
    OrPredicate
    Predicate implementation that returns true if either of the predicates return true.
    PredicateDecorator
    Defines a predicate that decorates one or more other predicates.
    PredicateTransformer
    Transformer implementation that calls a Predicate using the input object and then returns the input.
    PrototypeFactory
    Factory implementation that creates a new instance each time based on a prototype.
    StringValueTransformer
    Transformer implementation that returns the result of calling String.valueOf on the input object.
    SwitchClosure
    Closure implementation calls the closure whose predicate returns true, like a switch statement.
    SwitchTransformer
    Transformer implementation calls the transformer whose predicate returns true, like a switch statement.
    TransformedPredicate
    Predicate implementation that transforms the given object before invoking another Predicate.
    TransformerClosure
    Closure implementation that calls a Transformer using the input object and ignore the result.
    TransformerPredicate
    Predicate implementation that returns the result of a transformer.
    TruePredicate
    Predicate implementation that always returns true.
    UniquePredicate
    Predicate implementation that returns true the first time an object is passed into the predicate.
    WhileClosure
    Closure implementation that executes a closure repeatedly until a condition is met, like a do-while or while loop.