设计模式之适配器模式

现实生活中一些适配器例子

例题：用火鸡冒充鸭子

适配器模式原理：
适配器模式：将一个类的接口转换成另一种接口.让原本接口不兼容的类可以兼容.

从用户的角度看不到被适配者，是解耦的
用户调用适配器转化出来的目标接口方法
适配器再调用被适配者的相关接口方法
用户收到反馈结果，感觉只是和目标接口交互

对象适配器

public class Turkey2DuckAdapter implements Duck{    private Turkey turkey;    public Turkey2DuckAdapter(Turkey turkey)    {        this.turkey=turkey;    }    @Override    public void quack()    {        turkey.gobble();    }    @Override    public void fly()    {        for (int i = 0; i < 3; i++)        {            turkey.fly();        }    }}

类适配器

类适配器：通过多重继承目标接口和被适配者类方式来实现适配

多重继承，其中继承的目标接口部分达到适配目的，而继承被适配者类的部分达
到通过调用被适配者类里的方法来实现目标接口的功能

public class Turkey2DuckClassAdapter extends WildTurkey implements Duck{    @Override    public void quack()    {        super.gobble();    }    @Override    public void fly()    {        for (int i = 0; i < 3; i++)        {            super.fly();            }    }}

对象适配器与类适配器差异

实际应用：从java枚举器到迭代器的适配

public class Enumeration2Iteration implements Iterator<Object>{    private Enumeration<Object> enumeration;    @Override    public boolean hasNext()    {        return enumeration.hasMoreElements();    }    @Override    public Object next()    {        return enumeration.nextElement();    }    @Override    public void remove()    {        throw new UnsupportedOperationException();    }}

实际应用2：Java的SynchronizedMap

 /**     * @serial include     */    private static class SynchronizedMap<K,V>        implements Map<K,V>, Serializable {        private static final long serialVersionUID = 1978198479659022715L;        private final Map<K,V> m;     // Backing Map        final Object      mutex;        // Object on which to synchronize        SynchronizedMap(Map<K,V> m) {            this.m = Objects.requireNonNull(m);            mutex = this;        }        SynchronizedMap(Map<K,V> m, Object mutex) {            this.m = m;            this.mutex = mutex;        }        public int size() {            synchronized (mutex) {return m.size();}        }        public boolean isEmpty() {            synchronized (mutex) {return m.isEmpty();}        }        public boolean containsKey(Object key) {            synchronized (mutex) {return m.containsKey(key);}        }        public boolean containsValue(Object value) {            synchronized (mutex) {return m.containsValue(value);}

code Address

http://download.csdn.net/detail/kaikai_sk/9873278