2、集合--Collection、Map、Set、List、Compareable、Iterator接口的源码

 首先对Connection的源码进行分析：

public interface Collection<E> extends Iterable<E> {
　　//返回当前集合中元素的数量
    int size();

　　//判断集合中是否含有元素
    boolean isEmpty();

　　//查找集合中是由含有对象o
    boolean contains(Object o);

　　//返回一个迭代器用于访问集合中的每一个集合
    Iterator<E> iterator();

　　//返回一个内涵集合所有元素的array
    Object[] toArray();

　　//返回一个内含所有元素的array。运行期间返回的array和a的类型相同，需要转换为正确的类型
    <T> T[] toArray(T[] a);

　
　　//将对象添加到集合
    boolean add(E e);

　　//如果集合中的有与元素o相匹配的对象，将其删除
    boolean remove(Object o);

　　//查找的集合中的元素是否含有集合c中的所有元素
    boolean containsAll(Collection<?> c);
　　
　　//将集合c中的yuans都添加到集合中
    boolean addAll(Collection<? extends E> c);
　　
　　//从集合中删除所有的c集合中所包含的元素
    boolean removeAll(Collection<?> c);
　　
　　
    default boolean removeIf(Predicate<? super E> filter) {
        Objects.requireNonNull(filter);
        boolean removed = false;
        final Iterator<E> each = iterator();
        while (each.hasNext()) {
            if (filter.test(each.next())) {
                each.remove();
                removed = true;
            }
        }
        return removed;
    }


　　//从集合中删除集合c中没有的元素
    boolean retainAll(Collection<?> c);
　　
　　//删除集合种的所有元素
    void clear();
　　
    boolean equals(Object o);

    int hashCode();

    @Override
    default Spliterator<E> spliterator() {
        return Spliterators.spliterator(this, 0);
    }

    default Stream<E> stream() {
        return StreamSupport.stream(spliterator(), false);
    }

    default Stream<E> parallelStream() {
        return StreamSupport.stream(spliterator(), true);
    }
}

 

Iterator源码

public interface Iterator<E> {
　　//判断是否存在另一个可访问的接口
    boolean hasNext();
　　
　　//返回要访问的下一个元素
    E next();

　　//删除上次访问的对象
    default void remove() {
        throw new UnsupportedOperationException("remove");
    }


    default void forEachRemaining(Consumer<? super E> action) {
        Objects.requireNonNull(action);
        while (hasNext())
            action.accept(next());
    }
}

 

 

List源码

public interface List<E> extends Collection<E> {
　　
　　//返回当前集合中元素的数量
    int size();

　　//判断当前元素是否含有元素
    boolean isEmpty();

　　//查找集合中是否包含对象o
    boolean contains(Object o);

　　//返回一个内含集合中元素的array
    Object[] toArray();

　　//返回一个内含所有元素的array，运行期间返回array和a类型相同，需要转换为正确的类型
    <T> T[] toArray(T[] a);

　　//将兑现e添加到集合
    boolean add(E e);

　　//如果集合中有与元素o相匹配的对象，将其删除
    boolean remove(Object o);

　　//查找集合中的元素是否含有集合c中的所有元素
    boolean containsAll(Collection<?> c);

　　//将集合c中的元素都添加到集合中
    boolean addAll(Collection<? extends E> c);

　　//将集合中c中元素添加在指定的位置
    boolean addAll(int index, Collection<? extends E> c);

　　//从集合中删除c集合包含的所有元素
    boolean removeAll(Collection<?> c);

　　//从集合中删除c中元素不包含的元素
    boolean retainAll(Collection<?> c);


    default void replaceAll(UnaryOperator<E> operator) {
        Objects.requireNonNull(operator);
        final ListIterator<E> li = this.listIterator();
        while (li.hasNext()) {
            li.set(operator.apply(li.next()));
        }
    }


    @SuppressWarnings({"unchecked", "rawtypes"})
    default void sort(Comparator<? super E> c) {
        Object[] a = this.toArray();
        Arrays.sort(a, (Comparator) c);
        ListIterator<E> i = this.listIterator();
        for (Object e : a) {
            i.next();
            i.set((E) e);
        }
    }

　　//删除集合中的所有元素
    void clear();


    boolean equals(Object o);


    int hashCode();

　　//返回指定位置的元素
    E get(int index);

　　//用元素element元素代替index位置上的元素
    E set(int index, E element);

    void add(int index, E element);

 　　//删除指定位置上的元素
    E remove(int index);

　　//返回第一次出现元素o的位置，如果没有元素o则返回-1
    int indexOf(Object o);

　　//返回最后一次出现元素o的位置，如果没有该元素则返回-1
    int lastIndexOf(Object o);

　　//返回一个列表迭代器，用来访问列表中的元素
    ListIterator<E> listIterator();

　　//返回一个列表迭代器，用来从指定位置index开始访问列表中的元素
    ListIterator<E> listIterator(int index);

　　//返回指定位置fromIndex到toIndex范围中各个元素的列表视图
    List<E> subList(int fromIndex, int toIndex);


    @Override
    default Spliterator<E> spliterator() {
        return Spliterators.spliterator(this, Spliterator.ORDERED);
    }
}

 

 

Set接口：

各个方法和上述的方法基本一致

public interface Set<E> extends Collection<E> {

　　//
    int size();

    boolean isEmpty();

    boolean contains(Object o);

    Iterator<E> iterator();
 
    Object[] toArray();

    <T> T[] toArray(T[] a);

    boolean add(E e);

    boolean remove(Object o);

    boolean containsAll(Collection<?> c);

    boolean addAll(Collection<? extends E> c);

    boolean retainAll(Collection<?> c);

    boolean removeAll(Collection<?> c);

    void clear();
 
    boolean equals(Object o);

    int hashCode();
   
    @Override
    default Spliterator<E> spliterator() {
        return Spliterators.spliterator(this, Spliterator.DISTINCT);
    }
}

 

 

Map源码：

public interface Map<K,V> {
　　//返回当前映像中映射的数量
    int size();

　　//判断当前映像中映射的数量
    boolean isEmpty();

　　//判断映像中是否存在关键字key
    boolean containsKey(Object key);

　　//判断当前映像中是否存在值value
    boolean containsValue(Object value);

　　//获得与关键字key相关的值，并且返回与关键字key相关的对象
　　　　如果没有在该映像中找到关键字，则返回null
    V get(Object key);

　　//将相互关联的一个关键字与一个值放入该映像
　　　　如果关键之已经存在，那么旧值会被新值取代
    V put(K key, V value);

　　//从映像中删除与key相关的映射
    V remove(Object key);

　　//将来自特定映像的所有元素添加给该对象
    void putAll(Map<? extends K, ? extends V> m);
　　
　　//清除所有的映像
    void clear();

　　//返回映像中所有的关键字视图集
    Set<K> keySet();

　　//返回映像中所有值的视图集
    Collection<V> values();

　　//返回Map.Entry对象的视图集
    Set<Map.Entry<K, V>> entrySet();

  
    interface Entry<K,V> {

        K getKey();


        V getValue();

      
        V setValue(V value);

        boolean equals(Object o);

        int hashCode();
   
        public static <K extends Comparable<? super K>, V> Comparator<Map.Entry<K,V>> comparingByKey() {
            return (Comparator<Map.Entry<K, V>> & Serializable)
                (c1, c2) -> c1.getKey().compareTo(c2.getKey());
        }
    
        public static <K, V extends Comparable<? super V>> Comparator<Map.Entry<K,V>> comparingByValue() {
            return (Comparator<Map.Entry<K, V>> & Serializable)
                (c1, c2) -> c1.getValue().compareTo(c2.getValue());
        }

        public static <K, V> Comparator<Map.Entry<K, V>> comparingByKey(Comparator<? super K> cmp) {
            Objects.requireNonNull(cmp);
            return (Comparator<Map.Entry<K, V>> & Serializable)
                (c1, c2) -> cmp.compare(c1.getKey(), c2.getKey());
        }
        public static <K, V> Comparator<Map.Entry<K, V>> comparingByValue(Comparator<? super V> cmp) {
            Objects.requireNonNull(cmp);
            return (Comparator<Map.Entry<K, V>> & Serializable)
                (c1, c2) -> cmp.compare(c1.getValue(), c2.getValue());
        }
    }
 
    boolean equals(Object o);

    int hashCode();

    default V getOrDefault(Object key, V defaultValue) {
        V v;
        return (((v = get(key)) != null) || containsKey(key))
            ? v
            : defaultValue;
    }

    default void forEach(BiConsumer<? super K, ? super V> action) {
        Objects.requireNonNull(action);
        for (Map.Entry<K, V> entry : entrySet()) {
            K k;
            V v;
            try {
                k = entry.getKey();
                v = entry.getValue();
            } catch(IllegalStateException ise) {
                // this usually means the entry is no longer in the map.
                throw new ConcurrentModificationException(ise);
            }
            action.accept(k, v);
        }
    }

    default void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
        Objects.requireNonNull(function);
        for (Map.Entry<K, V> entry : entrySet()) {
            K k;
            V v;
            try {
                k = entry.getKey();
                v = entry.getValue();
            } catch(IllegalStateException ise) {
                // this usually means the entry is no longer in the map.
                throw new ConcurrentModificationException(ise);
            }

            // ise thrown from function is not a cme.
            v = function.apply(k, v);

            try {
                entry.setValue(v);
            } catch(IllegalStateException ise) {
                // this usually means the entry is no longer in the map.
                throw new ConcurrentModificationException(ise);
            }
        }
    }
 
    default V putIfAbsent(K key, V value) {
        V v = get(key);
        if (v == null) {
            v = put(key, value);
        }

        return v;
    }

    default boolean remove(Object key, Object value) {
        Object curValue = get(key);
        if (!Objects.equals(curValue, value) ||
            (curValue == null && !containsKey(key))) {
            return false;
        }
        remove(key);
        return true;
    }
    default boolean replace(K key, V oldValue, V newValue) {
        Object curValue = get(key);
        if (!Objects.equals(curValue, oldValue) ||
            (curValue == null && !containsKey(key))) {
            return false;
        }
        put(key, newValue);
        return true;
    }
  
    default V replace(K key, V value) {
        V curValue;
        if (((curValue = get(key)) != null) || containsKey(key)) {
            curValue = put(key, value);
        }
        return curValue;
    }

    default V computeIfAbsent(K key,
            Function<? super K, ? extends V> mappingFunction) {
        Objects.requireNonNull(mappingFunction);
        V v;
        if ((v = get(key)) == null) {
            V newValue;
            if ((newValue = mappingFunction.apply(key)) != null) {
                put(key, newValue);
                return newValue;
            }
        }
        return v;
    }
   
    default V computeIfPresent(K key,
            BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
        Objects.requireNonNull(remappingFunction);
        V oldValue;
        if ((oldValue = get(key)) != null) {
            V newValue = remappingFunction.apply(key, oldValue);
            if (newValue != null) {
                put(key, newValue);
                return newValue;
            } else {
                remove(key);
                return null;
            }
        } else {
            return null;
        }
    }

    default V compute(K key,
            BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
        Objects.requireNonNull(remappingFunction);
        V oldValue = get(key);

        V newValue = remappingFunction.apply(key, oldValue);
        if (newValue == null) {
            // delete mapping
            if (oldValue != null || containsKey(key)) {
                // something to remove
                remove(key);
                return null;
            } else {
                // nothing to do. Leave things as they were.
                return null;
            }
        } else {
            // add or replace old mapping
            put(key, newValue);
            return newValue;
        }
    }

    default V merge(K key, V value,
            BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
        Objects.requireNonNull(remappingFunction);
        Objects.requireNonNull(value);
        V oldValue = get(key);
        V newValue = (oldValue == null) ? value :
                   remappingFunction.apply(oldValue, value);
        if(newValue == null) {
            remove(key);
        } else {
            put(key, newValue);
        }
        return newValue;
    }
}

 

 

Compareable接口

@FunctionalInterface
public interface Comparator<T> {
  
　　//能够对o1和2两个对象进行比较，如果o1位于o2的前面则返回负值
　　　　如果在排序中认为o1和o2是相同的值，则返回0
　　　　如果o1位于o2的后面则返回正值
    int compare(T o1, T o2);

   //指示对象是否和obj相同
    boolean equals(Object obj);
   
    default Comparator<T> reversed() {
        return Collections.reverseOrder(this);
    }

    
    default Comparator<T> thenComparing(Comparator<? super T> other) {
        Objects.requireNonNull(other);
        return (Comparator<T> & Serializable) (c1, c2) -> {
            int res = compare(c1, c2);
            return (res != 0) ? res : other.compare(c1, c2);
        };
    }

  
    default <U> Comparator<T> thenComparing(
            Function<? super T, ? extends U> keyExtractor,
            Comparator<? super U> keyComparator)
    {
        return thenComparing(comparing(keyExtractor, keyComparator));
    }

    
    default <U extends Comparable<? super U>> Comparator<T> thenComparing(
            Function<? super T, ? extends U> keyExtractor)
    {
        return thenComparing(comparing(keyExtractor));
    }

   
    default Comparator<T> thenComparingInt(ToIntFunction<? super T> keyExtractor) {
        return thenComparing(comparingInt(keyExtractor));
    }

  
    default Comparator<T> thenComparingLong(ToLongFunction<? super T> keyExtractor) {
        return thenComparing(comparingLong(keyExtractor));
    }

   
    default Comparator<T> thenComparingDouble(ToDoubleFunction<? super T> keyExtractor) {
        return thenComparing(comparingDouble(keyExtractor));
    }

    public static <T extends Comparable<? super T>> Comparator<T> reverseOrder() {
        return Collections.reverseOrder();
    }

  
    @SuppressWarnings("unchecked")
    public static <T extends Comparable<? super T>> Comparator<T> naturalOrder() {
        return (Comparator<T>) Comparators.NaturalOrderComparator.INSTANCE;
    }

 
    public static <T> Comparator<T> nullsFirst(Comparator<? super T> comparator) {
        return new Comparators.NullComparator<>(true, comparator);
    }

   
    public static <T> Comparator<T> nullsLast(Comparator<? super T> comparator) {
        return new Comparators.NullComparator<>(false, comparator);
    }

   
    public static <T, U> Comparator<T> comparing(
            Function<? super T, ? extends U> keyExtractor,
            Comparator<? super U> keyComparator)
    {
        Objects.requireNonNull(keyExtractor);
        Objects.requireNonNull(keyComparator);
        return (Comparator<T> & Serializable)
            (c1, c2) -> keyComparator.compare(keyExtractor.apply(c1),
                                              keyExtractor.apply(c2));
    }

  
    public static <T, U extends Comparable<? super U>> Comparator<T> comparing(
            Function<? super T, ? extends U> keyExtractor)
    {
        Objects.requireNonNull(keyExtractor);
        return (Comparator<T> & Serializable)
            (c1, c2) -> keyExtractor.apply(c1).compareTo(keyExtractor.apply(c2));
    }

    public static <T> Comparator<T> comparingInt(ToIntFunction<? super T> keyExtractor) {
        Objects.requireNonNull(keyExtractor);
        return (Comparator<T> & Serializable)
            (c1, c2) -> Integer.compare(keyExtractor.applyAsInt(c1), keyExtractor.applyAsInt(c2));
    }

    public static <T> Comparator<T> comparingLong(ToLongFunction<? super T> keyExtractor) {
        Objects.requireNonNull(keyExtractor);
        return (Comparator<T> & Serializable)
            (c1, c2) -> Long.compare(keyExtractor.applyAsLong(c1), keyExtractor.applyAsLong(c2));
    }

    
    public static<T> Comparator<T> comparingDouble(ToDoubleFunction<? super T> keyExtractor) {
        Objects.requireNonNull(keyExtractor);
        return (Comparator<T> & Serializable)
            (c1, c2) -> Double.compare(keyExtractor.applyAsDouble(c1), keyExtractor.applyAsDouble(c2));
    }
}

 

以上是对主要的6个接口进行分析

其余的在之后的测试中有需要时在进行分析