【源码】Set集合源码剖析

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注：以下源码基于jdk1.7.0_11

static final long serialVersionUID = -5024744406713321676L;
    private transient HashMap<E,Object> map;//内部封装了HashMap
    // Dummy value to associate with an Object in the backing Map
    private static final Object PRESENT = new Object();//值固定为new Object
    /*构造器照搬HashMap的*/
    public HashSet() {
        map = new HashMap<>();
    }

    public HashSet(Collection<? extends E> c) {
        map = new HashMap<>(Math.max((int) (c.size()/.75f) + 1, 16));
        addAll(c);
    }

    public HashSet(int initialCapacity, float loadFactor) {
        map = new HashMap<>(initialCapacity, loadFactor);
    }
    public HashSet(int initialCapacity) {
        map = new HashMap<>(initialCapacity);
    }

    HashSet(int initialCapacity, float loadFactor, boolean dummy) {
        map = new LinkedHashMap<>(initialCapacity, loadFactor);
    }

  public boolean add(E e) {
        return map.put(e, PRESENT)==null;
    }

 public boolean remove(Object o) {
        return map.remove(o)==PRESENT;
    }

private transient NavigableMap<E,Object> m;
    // Dummy value to associate with an Object in the backing Map
    private static final Object PRESENT = new Object();

    TreeSet(NavigableMap<E,Object> m) {
        this.m = m;
    }

    public TreeSet() {//内部是TreeSet
        this(new TreeMap<E,Object>());
    }

    public TreeSet(Comparator<? super E> comparator) {
        this(new TreeMap<>(comparator));
    }
  
    public TreeSet(Collection<? extends E> c) {
        this();
        addAll(c);
    }

    public TreeSet(SortedSet<E> s) {
        this(s.comparator());
        addAll(s);
    }

    public boolean add(E e) {
        return m.put(e, PRESENT)==null;
    }
 public boolean remove(Object o) {
        return m.remove(o)==PRESENT;
    }

【源码】Set集合源码剖析

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原文地址：http://blog.csdn.net/chdjj/article/details/38783931