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本文主要研究一下nacos的DelegateConsistencyServiceImpl

ConsistencyService

nacos-1.1.3/naming/src/main/java/com/alibaba/nacos/naming/consistency/ConsistencyService.java

public interface ConsistencyService {    /**     * Put a data related to a key to Nacos cluster     *     * @param key   key of data, this key should be globally unique     * @param value value of data     * @throws NacosException     * @see     */    void put(String key, Record value) throws NacosException;    /**     * Remove a data from Nacos cluster     *     * @param key key of data     * @throws NacosException     */    void remove(String key) throws NacosException;    /**     * Get a data from Nacos cluster     *     * @param key key of data     * @return data related to the key     * @throws NacosException     */    Datum get(String key) throws NacosException;    /**     * Listen for changes of a data     *     * @param key      key of data     * @param listener callback of data change     * @throws NacosException     */    void listen(String key, RecordListener listener) throws NacosException;    /**     * Cancel listening of a data     *     * @param key      key of data     * @param listener callback of data change     * @throws NacosException     */    void unlisten(String key, RecordListener listener) throws NacosException;    /**     * Tell the status of this consistency service     *     * @return true if available     */    boolean isAvailable();}
  • ConsistencyService定义了put、remove、get、listen、unlisten、isAvailable方法

DelegateConsistencyServiceImpl

nacos-1.1.3/naming/src/main/java/com/alibaba/nacos/naming/consistency/DelegateConsistencyServiceImpl.java

@Service("consistencyDelegate")public class DelegateConsistencyServiceImpl implements ConsistencyService {    @Autowired    private PersistentConsistencyService persistentConsistencyService;    @Autowired    private EphemeralConsistencyService ephemeralConsistencyService;    @Override    public void put(String key, Record value) throws NacosException {        mapConsistencyService(key).put(key, value);    }    @Override    public void remove(String key) throws NacosException {        mapConsistencyService(key).remove(key);    }    @Override    public Datum get(String key) throws NacosException {        return mapConsistencyService(key).get(key);    }    @Override    public void listen(String key, RecordListener listener) throws NacosException {        // this special key is listened by both:        if (KeyBuilder.SERVICE_META_KEY_PREFIX.equals(key)) {            persistentConsistencyService.listen(key, listener);            ephemeralConsistencyService.listen(key, listener);            return;        }        mapConsistencyService(key).listen(key, listener);    }    @Override    public void unlisten(String key, RecordListener listener) throws NacosException {        mapConsistencyService(key).unlisten(key, listener);    }    @Override    public boolean isAvailable() {        return ephemeralConsistencyService.isAvailable() && persistentConsistencyService.isAvailable();    }    private ConsistencyService mapConsistencyService(String key) {        return KeyBuilder.matchEphemeralKey(key) ? ephemeralConsistencyService : persistentConsistencyService;    }}
  • DelegateConsistencyServiceImpl实现了ConsistencyService接口；其put、remove、get、listen、unlisten方法内部都使用了mapConsistencyService来判断是使用ephemeralConsistencyService还persistentConsistencyService；其isAvailable方法要求ephemeralConsistencyService及persistentConsistencyService都是available

小结

ConsistencyService定义了put、remove、get、listen、unlisten、isAvailable方法；DelegateConsistencyServiceImpl实现了ConsistencyService接口；其put、remove、get、listen、unlisten方法内部都使用了mapConsistencyService来判断是使用ephemeralConsistencyService还persistentConsistencyService；其isAvailable方法要求ephemeralConsistencyService及persistentConsistencyService都是available

doc

  • DelegateConsistencyServiceImpl