| /* |
| * Copyright 2000-2014 JetBrains s.r.o. |
| * |
| * 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.intellij.util.containers; |
| |
| import gnu.trove.THashSet; |
| import gnu.trove.TObjectHashingStrategy; |
| import gnu.trove.TObjectProcedure; |
| import org.jetbrains.annotations.NotNull; |
| |
| import java.lang.reflect.Array; |
| import java.util.Collection; |
| import java.util.ConcurrentModificationException; |
| import java.util.Iterator; |
| import java.util.Set; |
| |
| /** |
| * Hash set (based on THashSet) which is fast when contains one or zero elements (avoids to calculate hash codes and call equals whenever possible). |
| * For other sizes it delegates to THashSet. |
| * Null keys are NOT PERMITTED. |
| */ |
| public class SmartHashSet<T> extends THashSet<T> { |
| private T theElement; // contains the only element if size() == 1 |
| |
| public SmartHashSet() { |
| } |
| |
| public SmartHashSet(@NotNull TObjectHashingStrategy<T> strategy) { |
| super(strategy); |
| } |
| |
| public SmartHashSet(int initialCapacity) { |
| super(initialCapacity); |
| } |
| |
| public SmartHashSet(int initialCapacity, TObjectHashingStrategy<T> strategy) { |
| super(initialCapacity, strategy); |
| } |
| |
| public SmartHashSet(int initialCapacity, float loadFactor) { |
| super(initialCapacity, loadFactor); |
| } |
| |
| public SmartHashSet(int initialCapacity, float loadFactor, TObjectHashingStrategy<T> strategy) { |
| super(initialCapacity, loadFactor, strategy); |
| } |
| |
| public SmartHashSet(Collection<? extends T> collection) { |
| super(collection); |
| } |
| |
| public SmartHashSet(Collection<? extends T> collection, TObjectHashingStrategy<T> strategy) { |
| super(collection, strategy); |
| } |
| |
| @Override |
| public boolean contains(@NotNull Object obj) { |
| T theElement = this.theElement; |
| if (theElement != null) { |
| return eq(theElement, (T)obj); |
| } |
| return !super.isEmpty() && super.contains(obj); |
| } |
| |
| @Override |
| public boolean add(@NotNull T obj) { |
| T theElement = this.theElement; |
| if (theElement != null) { |
| if (eq(theElement, obj)) return false; |
| super.add(theElement); |
| this.theElement = null; |
| // fallthrough |
| } |
| else if (super.isEmpty()) { |
| this.theElement = obj; |
| return true; |
| } |
| return super.add(obj); |
| } |
| |
| private boolean eq(T obj, T theElement) { |
| return theElement == obj || _hashingStrategy.equals(theElement, obj); |
| } |
| |
| @Override |
| public boolean equals(@NotNull Object other) { |
| T theElement = this.theElement; |
| if (theElement != null) { |
| return other instanceof Set && ((Set)other).size() == 1 && eq(theElement, (T)((Set)other).iterator().next()); |
| } |
| |
| return super.equals(other); |
| } |
| |
| @Override |
| public int hashCode() { |
| T theElement = this.theElement; |
| if (theElement != null) { |
| return _hashingStrategy.computeHashCode(theElement); |
| } |
| return super.hashCode(); |
| } |
| |
| @Override |
| public void clear() { |
| theElement = null; |
| super.clear(); |
| } |
| |
| @Override |
| public int size() { |
| T theElement = this.theElement; |
| if (theElement != null) { |
| return 1; |
| } |
| return super.size(); |
| } |
| |
| @Override |
| public boolean isEmpty() { |
| T theElement = this.theElement; |
| return theElement == null && super.isEmpty(); |
| } |
| |
| @Override |
| public boolean remove(@NotNull Object obj) { |
| T theElement = this.theElement; |
| if (theElement != null) { |
| if (eq(theElement, (T)obj)) { |
| this.theElement = null; |
| return true; |
| } |
| return false; |
| } |
| return super.remove(obj); |
| } |
| |
| @NotNull |
| @Override |
| public Iterator<T> iterator() { |
| if (theElement != null) { |
| return new SingletonIteratorBase<T>() { |
| @Override |
| protected void checkCoModification() { |
| if (theElement == null) { |
| throw new ConcurrentModificationException(); |
| } |
| } |
| |
| @Override |
| protected T getElement() { |
| return theElement; |
| } |
| |
| @Override |
| public void remove() { |
| checkCoModification(); |
| clear(); |
| } |
| }; |
| } |
| return super.iterator(); |
| } |
| |
| @Override |
| public boolean forEach(@NotNull TObjectProcedure<T> procedure) { |
| T theElement = this.theElement; |
| if (theElement != null) { |
| return procedure.execute(theElement); |
| } |
| return super.forEach(procedure); |
| } |
| |
| @NotNull |
| @Override |
| public Object[] toArray() { |
| T theElement = this.theElement; |
| if (theElement != null) { |
| return new Object[]{theElement}; |
| } |
| return super.toArray(); |
| } |
| |
| @NotNull |
| @Override |
| public <T> T[] toArray(@NotNull T[] a) { |
| T theElement = (T)this.theElement; |
| if (theElement != null) { |
| if (a.length == 0) { |
| a = (T[]) Array.newInstance(a.getClass().getComponentType(), 1); |
| } |
| a[0] = theElement; |
| if (a.length > 1) { |
| a[1] = null; |
| } |
| return a; |
| } |
| return super.toArray(a); |
| } |
| |
| } |