JDK中Collections的线程安全怎么实现
方法：
public static
Set synchronizedSet(Set s) { return new SynchronizedSet
(s); }
static class SynchronizedSet
extends SynchronizedCollection
implements Set
{ private static final long serialVersionUID = 487447009682186044L;
SynchronizedSet(Set
s) { super(s);
}
SynchronizedSet(Set
s, Object mutex) { super(s, mutex);
}
public boolean equals(Object o) {
synchronized(mutex) {return c.equals(o);}
}
public int hashCode() {
synchronized(mutex) {return c.hashCode();}
}
}
// use serialVersionUID from JDK 1.2.2 for interoperability
private static final long serialVersionUID = 3053995032091335093L;
final Collection
c; // Backing Collection final Object mutex; // Object on which to synchronize
SynchronizedCollection(Collection
c) { if (c==null)
throw new NullPointerException();
this.c = c;
mutex = this;
}
SynchronizedCollection(Collection
c, Object mutex) { this.c = c;
this.mutex = mutex;
}
public int size() {
synchronized(mutex) {return c.size();}
}
public boolean isEmpty() {
synchronized(mutex) {return c.isEmpty();}
}
public boolean contains(Object o) {
synchronized(mutex) {return c.contains(o);}
}
public Object[] toArray() {
synchronized(mutex) {return c.toArray();}
}
public
T[] toArray(T[] a) { synchronized(mutex) {return c.toArray(a);}
}
public Iterator
iterator() { return c.iterator(); // Must be manually synched by user!
}
public boolean add(E e) {
synchronized(mutex) {return c.add(e);}
}
public boolean remove(Object o) {
synchronized(mutex) {return c.remove(o);}
}
public boolean containsAll(Collection coll) {
synchronized(mutex) {return c.containsAll(coll);}
}
public boolean addAll(Collection coll) {
synchronized(mutex) {return c.addAll(coll);}
}
public boolean removeAll(Collection coll) {
synchronized(mutex) {return c.removeAll(coll);}
}
public boolean retainAll(Collection coll) {
synchronized(mutex) {return c.retainAll(coll);}
}
public void clear() {
synchronized(mutex) {c.clear();}
}
public String toString() {
synchronized(mutex) {return c.toString();}
}
private void writeObject(ObjectOutputStream s) throws IOException {
synchronized(mutex) {s.defaultWriteObject();}
}
}
List和Map方法同理，这样，我们利用了装实模式，给我们的Map和List穿上了交通协管员的制服，减少了类爆炸，这就是装实模式；
package org;
public class AImp implements IA {
public synchronized void say() {
;
}
}
package org;
public interface IA {
public void say();
}
sychronized标识符是不影响接口的实现和继承的
上一篇：JDK的Set源码分析
下一篇：如何编写字母全排列快速算法C代码