| /* |
| * Copyright (c) 2010, Rickard Öberg. All Rights Reserved. |
| * |
| * 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 org.qi4j.functional; |
| |
| import java.util.Iterator; |
| |
| /** |
| * When using Iterables with map() and filter() the code often reads "in reverse", with the first item last in the code. |
| * Example: Iterables.map(function,Iterables.filter(specification, iterable)) |
| * <p> |
| * This ForEach class reverses that order and makes the code more readable, and allows easy application of visitors on iterables. |
| * </p> |
| * <p> |
| * Example: forEach(iterable).filter(specification).map(function).visit(visitor) |
| * </p> |
| */ |
| public final class ForEach<T> |
| implements Iterable<T> |
| { |
| public static <T> ForEach<T> forEach( Iterable<T> iterable ) |
| { |
| return new ForEach<>( iterable ); |
| } |
| |
| private final Iterable<T> iterable; |
| |
| public ForEach( Iterable<T> iterable ) |
| { |
| this.iterable = iterable; |
| } |
| |
| @Override |
| public Iterator<T> iterator() |
| { |
| return iterable.iterator(); |
| } |
| |
| public ForEach<T> filter( Specification<? super T> specification ) |
| { |
| return new ForEach<>( Iterables.filter( specification, iterable ) ); |
| } |
| |
| public <TO> ForEach<TO> map( Function<? /* super T */, TO> function ) |
| { |
| return new ForEach<>( Iterables.map( function, iterable ) ); |
| } |
| |
| public <TO> ForEach<TO> flatten() |
| { |
| Iterable<Iterable<TO>> original = iterable(); |
| Iterable<TO> iterable1 = Iterables.flattenIterables( original ); |
| return new ForEach<>( iterable1 ); |
| } |
| |
| @SuppressWarnings( "unchecked" ) |
| private <TO> Iterable<Iterable<TO>> iterable() |
| { |
| return (Iterable<Iterable<TO>>) iterable; |
| } |
| |
| public T last() |
| { |
| T lastItem = null; |
| for( T item : iterable ) |
| { |
| lastItem = item; |
| } |
| return lastItem; |
| } |
| |
| public <ThrowableType extends Throwable> boolean visit( final Visitor<T, ThrowableType> visitor ) |
| throws ThrowableType |
| { |
| for( T item : iterable ) |
| { |
| if( !visitor.visit( item ) ) |
| { |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| } |