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Redis based In-Memory Data Grid for Java
/*
* Copyright (c) 2011-2014 Pivotal Software, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package reactor.fn;
import reactor.fn.tuple.Tuple2;
import java.lang.reflect.Constructor;
import java.util.concurrent.Callable;
import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicReference;
/**
* Helper methods to provide syntax sugar for working with functional components in Reactor.
*
* @author Jon Brisbin
* @author Stephane Maldini
* @author Andy Wilkinson
*/
@Deprecated
public abstract class Functions {
/**
* Chain a set of {@link Consumer Consumers} together into a single {@link Consumer}.
*
* @param consumers the {@link Consumer Consumers} to chain together
* @param type of the event handled by the {@link Consumer}
* @return a new {@link Consumer}
*/
@SafeVarargs
public static Consumer chain(Consumer... consumers) {
final AtomicReference> composition = new AtomicReference>();
for (final Consumer next : consumers) {
if (null == composition.get()) {
composition.set(next);
} else {
composition.set(new Consumer() {
final Consumer prev = composition.get();
public void accept(T t) {
prev.accept(t);
next.accept(t);
}
});
}
}
return composition.get();
}
/**
* Wrap the given {@link java.util.concurrent.Callable} and compose a new {@link Function}.
*
* @param c The {@link java.util.concurrent.Callable}.
* @return An {@link Consumer} that executes the {@link java.util.concurrent.Callable}.
*/
public static Function function(final Callable c) {
return new Function() {
@Override
public V apply(T o) {
try {
return c.call();
} catch (Exception e) {
throw new IllegalStateException(e);
}
}
};
}
/**
* Wrap a given {@link reactor.fn.Function} that applies transformation to a Tuple2 into a PairFunction.
*
* @param function tuple2 function to wrap into a PairFunction
* @return A {@link BiFunction} that delegates to a new applied tuple if called with 2 arguments an to the applied tuple itself.
*/
public static BiFunction pairFrom(final Function, V>
function) {
return new BiFunction() {
@Override
public V apply(LEFT left, RIGHT right) {
return function.apply(Tuple2.of(left, right));
}
};
}
/**
* Wrap a given {@link BiFunction} that applies transformation to a Tuple2 into a Function Tuple2.
*
* @param pairFunction PairFunction to wrap into a Function
* @return A {@link BiFunction} that delegates to a new applied tuple if called with 2 arguments an to the applied tuple itself.
*/
public static Function, V> functionFrom(final BiFunction
pairFunction) {
return new Function, V>() {
@Override
public V apply(Tuple2 tuple2) {
return pairFunction.apply(tuple2.t1, tuple2.t2);
}
};
}
/**
* Wrap the given {@link Runnable} and compose a new {@link Consumer}.
*
* @param r The {@link Runnable}.
* @return An {@link Consumer} that executes the {@link Runnable}.
*/
public static Consumer consumer(final Runnable r) {
return new Consumer() {
@Override
public void accept(T t) {
r.run();
}
};
}
/**
* Creates a {@code Supplier} that will always return the given {@code value}.
*
* @param value the value to be supplied
* @return the supplier for the value
*/
public static Supplier supplier(final T value) {
return new Supplier() {
@Override
public T get() {
return value;
}
};
}
/**
* Creates a {@code Supplier} that will return a new instance of {@code type} each time
* it's called.
*
* @param type The type to create
* @return The supplier that will create instances
* @throws IllegalArgumentException if {@code type} does not have a zero-args constructor
*/
public static Supplier supplier(final Class type) {
try {
final Constructor ctor = type.getConstructor();
return new Supplier() {
@Override
public T get() {
try {
return ctor.newInstance();
} catch (Exception e) {
throw new IllegalStateException(e.getMessage(), e);
}
}
};
} catch (NoSuchMethodException e) {
throw new IllegalArgumentException(e.getMessage(), e);
}
}
/**
* Creates a {@code Supplier} that will {@link Callable#call call} the {@code callable}
* each time it's asked for a value.
*
* @param callable The {@link Callable}.
* @return A {@link Supplier} that executes the {@link Callable}.
*/
public static Supplier supplier(final Callable callable) {
return new Supplier() {
@Override
public T get() {
try {
return callable.call();
} catch (Exception e) {
throw new IllegalStateException(e);
}
}
};
}
/**
* Creates a {@code Supplier} that will {@link Future#get get} its value from the
* {@code future} each time it's asked for a value.
*
* @param future The future to get values from
* @return A {@link Supplier} that gets its values from the Future
*/
public static Supplier supplier(final Future future) {
return new Supplier() {
@Override
public T get() {
try {
return future.get();
} catch (Exception e) {
throw new IllegalStateException(e);
}
}
};
}
}