001    /*
002     * Copyright 2010-2013 JetBrains s.r.o.
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     * http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     */
016    
017    package org.jetbrains.jet.util;
018    
019    import com.google.common.base.Supplier;
020    import com.google.common.collect.*;
021    
022    import java.util.Collection;
023    import java.util.List;
024    import java.util.Set;
025    
026    public class CommonSuppliers {
027        private CommonSuppliers() {}
028    
029        private static final Supplier<?> ARRAY_LIST_SUPPLIER = new Supplier() {
030            @Override
031            public List get() {
032                return Lists.newArrayList();
033            }
034        };
035    
036        private static final Supplier<?> LINKED_HASH_SET_SUPPLIER = new Supplier() {
037            @Override
038            public Set get() {
039                return Sets.newLinkedHashSet();
040            }
041        };
042    
043        private static final Supplier<?> HASH_SET_SUPPLIER = new Supplier() {
044            @Override
045            public Set get() {
046                return Sets.newHashSet();
047            }
048        };
049    
050        public static <T> Supplier<List<T>> getArrayListSupplier() {
051            //noinspection unchecked
052            return (Supplier<List<T>>) ARRAY_LIST_SUPPLIER;
053        }
054    
055        public static <T> Supplier<Set<T>> getLinkedHashSetSupplier() {
056            //noinspection unchecked
057            return (Supplier<Set<T>>) LINKED_HASH_SET_SUPPLIER;
058        }
059    
060        public static <T> Supplier<Set<T>> getHashSetSupplier() {
061            //noinspection unchecked
062            return (Supplier<Set<T>>) HASH_SET_SUPPLIER;
063        }
064    
065        public static <K, V> SetMultimap<K, V> newLinkedHashSetHashSetMultimap() {
066            return Multimaps.newSetMultimap(Maps.<K, Collection<V>>newHashMap(), CommonSuppliers.<V>getLinkedHashSetSupplier());
067        }
068    }