public enum Color { RED("红色", 1), GREEN("绿色", 2), BLANK("白色", 3), YELLO("黄色", 4); // 成员变量 private String name; private int index; // 构造方法 private Color(String name, int index) { this.name = name; this.index = index; } public static String getName(int index) { //利用了枚举自身的values()方法; for (Color c : Color.values()) { if (c.getIndex() == index) { return c.name; } } return null; } public String getName() { return name; } public void setName(String name) { this.name = name; } }问题:添加新方法只是得到了对于枚举实例不同的字符串描述信息。那么还有其他特殊的重要性吗??
下面是Floodlight controller中相关知识点的体现
public enum OFType { //这里自定义构造方法,有三个参数 HELLO (0, OFHello.class, new Instantiable<OFMessage>() { @Override public OFMessage instantiate() { return new OFHello(); }}), ERROR (1, OFError.class, new Instantiable<OFMessage>() { @Override public OFMessage instantiate() { return new OFError(); }}), PACKET_IN (10, OFPacketIn.class, new Instantiable<OFMessage>() { @Override public OFMessage instantiate() { return new OFPacketIn(); }}), PACKET_OUT (13, OFPacketOut.class, new Instantiable<OFMessage>() { @Override public OFMessage instantiate() { return new OFPacketOut(); }}), FLOW_MOD (14, OFFlowMod.class, new Instantiable<OFMessage>() { @Override public OFMessage instantiate() { return new OFFlowMod(); }}); static OFType[] mapping; //每个消息类型,都需要对应的具体实现类 protected Class<? extends OFMessage> clazz; //每个消息类的无参构造器 protected Constructor<? extends OFMessage> constructor; //接口 Instantiable 有一个初始化实例的方法,创建具体的OFMessage protected Instantiable<OFMessage> instantiable; //消息类型的值 protected byte type; /**构造方法 * Store some information about the OpenFlow type, including wire protocol * type number, length, and derived class * * @param type Wire protocol number associated with this OFType * @param requestClass The Java class corresponding to this type of OpenFlow message * @param instantiator An Instantiator<OFMessage> implementation that creates an * instance of the specified OFMessage */ OFType(int type, Class<? extends OFMessage> clazz, Instantiable<OFMessage> instantiator) { this.type = (byte) type; this.clazz = clazz; this.instantiable = instantiator; try { this.constructor = clazz.getConstructor(new Class[]{}); } catch (Exception e) { throw new RuntimeException("Failure getting constructor for class: " + clazz, e); } OFType.addMapping(this.type, this); //值到枚举类的映射 } /** * Adds a mapping from type value to OFType enum * * @param i OpenFlow wire protocol type * @param t type */ static public void addMapping(byte i, OFType t) { if (mapping == null) mapping = new OFType[32]; OFType.mapping[i] = t; } /** * Remove a mapping from type value to OFType enum * * @param i OpenFlow wire protocol type */ static public void removeMapping(byte i) { OFType.mapping[i] = null; } /** * Given a wire protocol OpenFlow type number, return the OFType associated * with it * * @param i wire protocol number * @return OFType enum type */ static public OFType valueOf(Byte i) { return OFType.mapping[i]; } /** * @return Returns the wire protocol value corresponding to this OFType */ public byte getTypeValue() { return this.type; } /** * @return return the OFMessage subclass corresponding to this OFType */ public Class<? extends OFMessage> toClass() { return clazz; } /** * Returns the no-argument Constructor of the implementation class for * this OFType * @return the constructor */ public Constructor<? extends OFMessage> getConstructor() { return constructor; } /** * Returns a new instance of the OFMessage represented by this OFType * @return the new object */ public OFMessage newInstance() { return instantiable.instantiate(); } /** * @return the instantiable */ public Instantiable<OFMessage> getInstantiable() { return instantiable; } /** * @param instantiable the instantiable to set */ public void setInstantiable(Instantiable<OFMessage> instantiable) { this.instantiable = instantiable; } }
向Java枚举类型中添加新方法,布布扣,bubuko.com
原文:http://blog.csdn.net/vonzhoufz/article/details/31740279