/**
* Copyright (C) 2011 Google 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 com.google.gimlet.commonality;
import com.google.common.base.Function;
/**
* This class provides convenience methods to facilitate using the behavior
* defined on {@link CommonalityDetector}.
*
* @author ffaber@gmail.com (Fred Faber)
*/
public final class CommonalityDetectors {
private CommonalityDetectors() { }
/**
* Returns a {@link CommonalityDetector} that uses the given function to
* extract values from its targets.
*/
public static <T, S> CommonalityDetector<T, S> forFunction(
Function<? super T, ? extends S> extractor) {
return new FunctionDrivenCommonalityDetector<T, S>(extractor);
}
/**
* Returns a {@link CommonalityDetector} which uses reflection to invoke
* the given no-arg method on its targets in order to extract the common value
* from each.
*/
@SuppressWarnings("unchecked")
public static <T, S> CommonalityDetector<T, S>
newReflexiveCommonalityDetector(String methodName) {
Function rawFunction = new GetValueViaReflectionFunction(methodName);
return forFunction(rawFunction);
}
/**
* Returns the result of detecting the common value of the given {@code items}
* through means of applying generic detection logic that uses the given
* {@code extractor}.
*/
@SuppressWarnings("unchecked")
public static <T, S> S detectCommonalityWithFunction(
Iterable<T> items, Function<? super T, ? extends S> extractor) {
// IntelliJ says the cast below is redundant, but compile fails without it.
return forFunction(extractor).detectCommonality((Iterable) items);
}
/**
* Returns the result of detecting the common value of the given {@code items}
* through means of invoking the given no-arg method that is expected to exist
* on each.
*/
@SuppressWarnings("unchecked")
public static <S> S detectCommonalityIntrospectively(
String methodName, Iterable<?> items) {
Function<Object, S> extractor =
new GetValueViaReflectionFunction<S>(methodName);
return forFunction(extractor).detectCommonality((Iterable) items);
}
}