Remove duplicate class in sentinel-core (#309)

ClusterTokenClient.java,TokenClientProvider.java in package `com.alibaba.csp.sentinel.cluster`

sentinel-core/src/main/java/com/alibaba/csp/sentinel/cluster/ClusterTokenClient.java

@@ -1,32 +0,0 @@
-/*
- * Copyright 1999-2018 Alibaba Group Holding Ltd.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.alibaba.csp.sentinel.cluster;
-
-/**
- * Token client interface for distributed flow control.
- *
- * @author Eric Zhao
- * @since 1.4.0
- */
-public interface ClusterTokenClient extends TokenService {
-
-    /**
-     * Get descriptor of current token server.
-     *
-     * @return current token server
-     */
-    TokenServerDescriptor currentServer();
-}

sentinel-core/src/main/java/com/alibaba/csp/sentinel/cluster/TokenClientProvider.java

@@ -1,61 +0,0 @@
-/*
- * Copyright 1999-2018 Alibaba Group Holding Ltd.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.alibaba.csp.sentinel.cluster;
-
-import java.util.ArrayList;
-import java.util.List;
-import java.util.ServiceLoader;
-
-import com.alibaba.csp.sentinel.log.RecordLog;
-
-/**
- * Provider for a universal {@link ClusterTokenClient} instance.
- *
- * @author Eric Zhao
- * @since 1.4.0
- */
-public final class TokenClientProvider {
-
-    private static ClusterTokenClient client = null;
-
-    private static final ServiceLoader<ClusterTokenClient> LOADER = ServiceLoader.load(ClusterTokenClient.class);
-
-    static {
-        // Not strictly thread-safe, but it's OK since it will be resolved only once.
-        resolveTokenClientInstance();
-    }
-
-    public static ClusterTokenClient getClient() {
-        return client;
-    }
-
-    private static void resolveTokenClientInstance() {
-        List<ClusterTokenClient> clients = new ArrayList<ClusterTokenClient>();
-        for (ClusterTokenClient client : LOADER) {
-            clients.add(client);
-        }
-
-        if (!clients.isEmpty()) {
-            // Get first.
-            client = clients.get(0);
-            RecordLog.info("[TokenClientProvider] Token client resolved: " + client.getClass().getCanonicalName());
-        } else {
-            RecordLog.warn("[TokenClientProvider] No existing token client, resolve failed");
-        }
-    }
-
-    private TokenClientProvider() {}
-}