添加简单Cache Util实现 DUBBO-475 ReferenceConfig支持按group+interface+version缓存

dubbo-config/dubbo-config-api/src/main/java/com/alibaba/dubbo/config/utils/ReferenceConfigCache.java

+/*
+ * Copyright 1999-2011 Alibaba Group.
+ *
+ * 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.dubbo.config.utils;
+
+import com.alibaba.dubbo.common.utils.StringUtils;
+import com.alibaba.dubbo.config.ReferenceConfig;
+
+import java.util.HashSet;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+
+/**
+ * a simple util class for cache {@link ReferenceConfig}.
+ * <p>
+ * {@link ReferenceConfig} is a heavy Object, it's necessary to cache these object
+ * for the framework which create {@link ReferenceConfig} frequently.
+ * <p>
+ * You can implement and use your own {@link ReferenceConfig} cache if you need use complicate strategy.
+ *
+ * @author ding.lid
+ */
+public class ReferenceConfigCache {
+    public static final String DEFAULT_NAME = "_DEFAULT_";
+
+    private static final ConcurrentMap<String, ReferenceConfigCache> cacheHolder = new ConcurrentHashMap<String, ReferenceConfigCache>();
+
+    /**
+     * Get the cache use default name and {@link #DEFAULT_KEY_GENERATOR} to generate cache key.
+     * Create cache if not existed yet.
+     */
+    public static ReferenceConfigCache getCache() {
+        return getCache(DEFAULT_NAME);
+    }
+
+    /**
+     * Get the cache use specified name and {@link KeyGenerator}.
+     * Create cache if not existed yet.
+     */
+    public static ReferenceConfigCache getCache(String name) {
+        return getCache(name, DEFAULT_KEY_GENERATOR);
+    }
+
+    /**
+     * Get the cache use specified {@link KeyGenerator}.
+     * Create cache if not existed yet.
+     */
+    public static ReferenceConfigCache getCache(String name, KeyGenerator keyGenerator) {
+        ReferenceConfigCache cache = cacheHolder.get(name);
+        if(cache != null) {
+            return cache;
+        }
+        cacheHolder.putIfAbsent(name, new ReferenceConfigCache(name, keyGenerator));
+        return cacheHolder.get(name);
+    }
+
+    public static interface KeyGenerator {
+        String generateKey(ReferenceConfig<?> referenceConfig);
+    }
+
+    /**
+     * Create the key with the <b>Group</b>, <b>Interface</b> and <b>version</b> attribute of {@link ReferenceConfig}.
+     * <p>
+     * eg: <code>group1/com.alibaba.foo.FooService:1.0.0</code>.
+     */
+    public static final KeyGenerator DEFAULT_KEY_GENERATOR = new KeyGenerator() {
+        public String generateKey(ReferenceConfig<?> referenceConfig) {
+            String iName = referenceConfig.getInterface();
+            if(StringUtils.isBlank(iName)) {
+                Class<?> clazz = referenceConfig.getInterfaceClass();
+                iName = clazz.getName();
+            }
+            if(StringUtils.isBlank(iName)) {
+                throw new IllegalArgumentException("No interface info in ReferenceConfig" + referenceConfig);
+            }
+
+            StringBuilder ret = new StringBuilder();
+            if(! StringUtils.isBlank(referenceConfig.getGroup())) {
+                ret.append(referenceConfig.getGroup()).append("/");
+            }
+            ret.append(iName);
+            if(! StringUtils.isBlank(referenceConfig.getVersion())) {
+                ret.append(":").append(referenceConfig.getVersion());
+            }
+            return ret.toString();
+        }
+    };
+
+    private final String name;
+    private final KeyGenerator generator;
+
+    private ConcurrentMap<String, ReferenceConfig<?>> cache = new ConcurrentHashMap<String, ReferenceConfig<?>>();
+
+    private ReferenceConfigCache(String name, KeyGenerator generator) {
+        this.name = name;
+        this.generator = generator;
+    }
+
+    public <T> T get(ReferenceConfig<T> referenceConfig) {
+        String key = generator.generateKey(referenceConfig);
+
+        ReferenceConfig<?> config = cache.get(key);
+        if(config != null) {
+            return referenceConfig.get();
+        }
+
+        cache.putIfAbsent(key, referenceConfig);
+        config = cache.get(key);
+        return (T) config.get();
+    }
+
+    void destroyKey(String key) {
+        ReferenceConfig<?> config = cache.remove(key);
+        if(config == null) return;
+        config.destroy();
+    }
+
+    /**
+     * clear and destroy one {@link ReferenceConfig} in the cache.
+     * @param referenceConfig use for create key.
+     */
+    public <T> void destroy(ReferenceConfig<T> referenceConfig) {
+        String key = generator.generateKey(referenceConfig);
+        destroyKey(key);
+    }
+
+    /**
+     * clear and destroy all {@link ReferenceConfig} in the cache.
+     */
+    public void destroyAll() {
+        Set<String> set = new HashSet<String>(cache.keySet());
+        for(String key : set) {
+            destroyKey(key);
+        }
+    }
+}