CMap: wrapper around DatabaseService
Change-Id: I55c534567b99d6bb7e95045c8100226c0b515a99
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/CMap.java b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/CMap.java
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+++ b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/CMap.java
@@ -0,0 +1,196 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * 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 org.onlab.onos.store.service.impl;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.base.Predicates.notNull;
+
+import java.util.Map;
+
+import org.onlab.onos.store.serializers.StoreSerializer;
+import org.onlab.onos.store.service.DatabaseAdminService;
+import org.onlab.onos.store.service.DatabaseService;
+import org.onlab.onos.store.service.VersionedValue;
+
+import com.google.common.base.Function;
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import com.google.common.collect.FluentIterable;
+
+/**
+ * Map like interface wrapper around DatabaseService.
+ *
+ * @param <K> Key type of the map.
+ * The type must have toString(), which can uniquely identify the entry.
+ * @param <V> Value type
+ */
+public class CMap<K, V> {
+
+ @SuppressWarnings("unused")
+ private final DatabaseAdminService dbAdminService;
+
+ private final DatabaseService dbService;
+
+ private final String tableName;
+ private final StoreSerializer serializer;
+
+ private final LoadingCache<K, String> keyCache;
+
+ /**
+ * Creates a CMap instance.
+ * It will create the table if necessary.
+ *
+ * @param dbAdminService
+ * @param dbService
+ * @param tableName table which this Map corresponds to
+ * @param serializer Value serializer
+ */
+ public CMap(DatabaseAdminService dbAdminService,
+ DatabaseService dbService,
+ String tableName,
+ StoreSerializer serializer) {
+
+ this.dbAdminService = checkNotNull(dbAdminService);
+ this.dbService = checkNotNull(dbService);
+ this.tableName = checkNotNull(tableName);
+ this.serializer = checkNotNull(serializer);
+
+ if (!dbAdminService.listTables().contains(tableName)) {
+ dbAdminService.createTable(tableName);
+ }
+
+ keyCache = CacheBuilder.newBuilder()
+ .softValues()
+ .build(new CacheLoader<K, String>() {
+
+ @Override
+ public String load(K key) {
+ return key.toString();
+ }
+ });
+ }
+
+ protected String sK(K key) {
+ return keyCache.getUnchecked(key);
+ }
+
+ protected byte[] sV(V val) {
+ return serializer.encode(val);
+ }
+
+ protected V dV(byte[] valBytes) {
+ return serializer.decode(valBytes);
+ }
+
+ /**
+ * Puts an entry to the map, if not already present.
+ *
+ * @param key the key of the value to put if absent
+ * @param value the value to be put if previous value does not exist
+ * @return true if put was successful.
+ */
+ public boolean putIfAbsent(K key, V value) {
+ return dbService.putIfAbsent(tableName, sK(key), sV(value));
+ }
+
+ /**
+ * Removes an entry associated to specified key.
+ *
+ * @param key key of the value to remove
+ * @return previous value in the map for the key
+ */
+ public V remove(K key) {
+ VersionedValue removed = dbService.remove(tableName, sK(key));
+ if (removed == null) {
+ return null;
+ }
+ return dV(removed.value());
+ }
+
+ /**
+ * Returns the size of the map.
+ *
+ * @return size of the map
+ */
+ public long size() {
+ // TODO this is very inefficient
+ return dbService.getAll(tableName).size();
+ }
+
+ /**
+ * Returns all the values contained in the map.
+ *
+ * @return values containd in this map
+ */
+ public Iterable<V> values() {
+ Map<String, VersionedValue> all = dbService.getAll(tableName);
+ return FluentIterable.from(all.values())
+ .transform(new Function<VersionedValue, V>() {
+
+ @Override
+ public V apply(VersionedValue input) {
+ if (input == null) {
+ return null;
+ }
+ return dV(input.value());
+ }
+ })
+ .filter(notNull());
+ }
+
+ /**
+ * Gets the value in the map.
+ *
+ * @param key to get from the map
+ * @return value associated with the key, null if not such entry
+ */
+ public V get(K key) {
+ VersionedValue vv = dbService.get(tableName, sK(key));
+ if (vv == null) {
+ return null;
+ }
+ return dV(vv.value());
+ }
+
+ /**
+ * Replaces the value in the map if the value matches the expected.
+ *
+ * @param key of the entry to replace
+ * @param oldVal value expected to be in the map
+ * @param newVal value to be replaced with
+ * @return true if successfully replaced
+ */
+ public boolean replace(K key, V oldVal, V newVal) {
+ return dbService.putIfValueMatches(tableName, sK(key), sV(oldVal), sV(newVal));
+ }
+
+ /**
+ * Puts a value int the map.
+ *
+ * @param key key with which the specified value is to be associated
+ * @param value value to be associated with the specified key
+ * @return previous value or null if not such entry
+ */
+ public V put(K key, V value) {
+ VersionedValue vv = dbService.put(tableName, sK(key), sV(value));
+ if (vv == null) {
+ return null;
+ }
+ return dV(vv.value());
+ }
+}
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