org.parboiled.common
Class Predicates

java.lang.Object
  extended by org.parboiled.common.Predicates

public final class Predicates
extends java.lang.Object


Method Summary
static
<T> Predicate<T>
alwaysFalse()
          Returns a predicate that always evaluates to false.
static
<T> Predicate<T>
alwaysTrue()
          Returns a predicate that always evaluates to true.
static
<T> Predicate<T>
and(java.util.Collection<? extends Predicate<? super T>> components)
          Returns a predicate that evaluates to true if each of its components evaluates to true.
static
<T> Predicate<T>
and(Predicate<? super T>... components)
          Returns a predicate that evaluates to true if each of its components evaluates to true.
static
<T> Predicate<T>
and(Predicate<? super T> first, Predicate<? super T> second)
          Returns a predicate that evaluates to true if both of its components evaluate to true.
static
<T> Predicate<T>
equalTo(T target)
          Returns a predicate that evaluates to true if the object being tested equals() the given target or both are null.
static
<T> Predicate<T>
in(java.util.Collection<? extends T> target)
          Returns a predicate that evaluates to true if the object reference being tested is a member of the given collection.
static Predicate<java.lang.Object> instanceOf(java.lang.Class<?> clazz)
          Returns a predicate that evaluates to true if the object being tested is an instance of the given class.
static
<T> Predicate<T>
isNull()
          Returns a predicate that evaluates to true if the object reference being tested is null.
static
<T> Predicate<T>
not(Predicate<T> predicate)
          Returns a predicate that evaluates to true if the given predicate evaluates to false.
static
<T> Predicate<T>
notNull()
          Returns a predicate that evaluates to true if the object reference being tested is not null.
static
<T> Predicate<T>
or(java.util.Collection<? extends Predicate<? super T>> components)
          Returns a predicate that evaluates to true if any one of its components evaluates to true.
static
<T> Predicate<T>
or(Predicate<? super T>... components)
          Returns a predicate that evaluates to true if any one of its components evaluates to true.
static
<T> Predicate<T>
or(Predicate<? super T> first, Predicate<? super T> second)
          Returns a predicate that evaluates to true if either of its components evaluates to true.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Method Detail

alwaysTrue

public static <T> Predicate<T> alwaysTrue()
Returns a predicate that always evaluates to true.

Returns:
a predicate

alwaysFalse

public static <T> Predicate<T> alwaysFalse()
Returns a predicate that always evaluates to false.

Returns:
a predicate

isNull

public static <T> Predicate<T> isNull()
Returns a predicate that evaluates to true if the object reference being tested is null.

Returns:
a predicate

notNull

public static <T> Predicate<T> notNull()
Returns a predicate that evaluates to true if the object reference being tested is not null.

Returns:
a predicate

not

public static <T> Predicate<T> not(Predicate<T> predicate)
Returns a predicate that evaluates to true if the given predicate evaluates to false.

Parameters:
predicate - the inner predicate
Returns:
a predicate

and

public static <T> Predicate<T> and(java.util.Collection<? extends Predicate<? super T>> components)
Returns a predicate that evaluates to true if each of its components evaluates to true. The components are evaluated in order, and evaluation will be "short-circuited" as soon as a false predicate is found. It defensively copies the iterable passed in, so future changes to it won't alter the behavior of this predicate. If components is empty, the returned predicate will always evaluate to true.

Parameters:
components - the components
Returns:
a predicate

and

public static <T> Predicate<T> and(Predicate<? super T>... components)
Returns a predicate that evaluates to true if each of its components evaluates to true. The components are evaluated in order, and evaluation will be "short-circuited" as soon as a false predicate is found. It defensively copies the array passed in, so future changes to it won't alter the behavior of this predicate. If components is empty, the returned predicate will always evaluate to true.

Parameters:
components - the components
Returns:
a predicate

and

public static <T> Predicate<T> and(Predicate<? super T> first,
                                   Predicate<? super T> second)
Returns a predicate that evaluates to true if both of its components evaluate to true. The components are evaluated in order, and evaluation will be "short-circuited" as soon as a false predicate is found.

Parameters:
first - the first
second - the second
Returns:
a predicate

or

public static <T> Predicate<T> or(java.util.Collection<? extends Predicate<? super T>> components)
Returns a predicate that evaluates to true if any one of its components evaluates to true. The components are evaluated in order, and evaluation will be "short-circuited" as soon as as soon as a true predicate is found. It defensively copies the iterable passed in, so future changes to it won't alter the behavior of this predicate. If components is empty, the returned predicate will always evaluate to false.

Parameters:
components - the components
Returns:
a predicate

or

public static <T> Predicate<T> or(Predicate<? super T>... components)
Returns a predicate that evaluates to true if any one of its components evaluates to true. The components are evaluated in order, and evaluation will be "short-circuited" as soon as as soon as a true predicate is found. It defensively copies the array passed in, so future changes to it won't alter the behavior of this predicate. If components is empty, the returned predicate will always evaluate to false.

Parameters:
components - the components
Returns:
a predicate

or

public static <T> Predicate<T> or(Predicate<? super T> first,
                                  Predicate<? super T> second)
Returns a predicate that evaluates to true if either of its components evaluates to true. The components are evaluated in order, and evaluation will be "short-circuited" as soon as as soon as a true predicate is found.

Parameters:
first - the first
second - the second
Returns:
a predicate

equalTo

public static <T> Predicate<T> equalTo(T target)
Returns a predicate that evaluates to true if the object being tested equals() the given target or both are null.

Parameters:
target - the target
Returns:
a predicate

instanceOf

public static Predicate<java.lang.Object> instanceOf(java.lang.Class<?> clazz)
Returns a predicate that evaluates to true if the object being tested is an instance of the given class. If the object being tested is null this predicate evaluates to false.

Parameters:
clazz - the clazz
Returns:
a predicate

in

public static <T> Predicate<T> in(java.util.Collection<? extends T> target)
Returns a predicate that evaluates to true if the object reference being tested is a member of the given collection. It does not defensively copy the collection passed in, so future changes to it will alter the behavior of the predicate.

This method can technically accept any Collection, but using a typed collection helps prevent bugs. This approach doesn't block any potential users since it is always possible to use Predicates.<Object>in().

Parameters:
target - the collection that may contain the function input
Returns:
a predicate