/**
* 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.cobar.client.router;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.alibaba.cobar.client.router.rules.IRoutingRule;
import com.alibaba.cobar.client.router.support.IBatisRoutingFact;
import com.alibaba.cobar.client.router.support.RoutingResult;
import com.alibaba.cobar.client.support.LRUMap;
import com.alibaba.cobar.client.support.utils.CollectionUtils;
/**
* CobarInternalRouter is the default router that will be used in cobar client,
* but it will not be the only one.<br>
* if it can't meet the needs, we can provide other {@link ICobarRouter} like a
* one that use rule engines.<br>
* for now, CobarInternalRouter will hold 4 set of routing rules:
* <ol>
* <li>sqlActionShardingRules
* <li>
* <li>sqlActionRules
* <li>
* <li>namespaceShardingRules
* <li>
* <li>namespaceRules
* <li>
* </ol>
* rules start with "sqlAction" are rules that will exactly match against the
* sql-map action id in the routing fact, while rules start with "namesapce"
* just match against the "namespace" part in the sql action id; we will match
* these rules in sequence against the routing fact, each later rule will be
* used as fall-back rule if former match fails.<br>
* To enhance the rule matching performance, we add a LRU cache, you can decide
* whether to use this cache by set the {@link #enableCache} property's value to
* true or false.<br>
*
* @author fujohnwang
* @since 1.0
*/
public class CobarClientInternalRouter implements ICobarRouter<IBatisRoutingFact> {
private transient final Logger logger = LoggerFactory.getLogger(CobarClientInternalRouter.class);
private LRUMap localCache;
private boolean enableCache = false;
public CobarClientInternalRouter(boolean enableCache) {
this(enableCache, 10000);
}
public CobarClientInternalRouter(int cacheSize) {
this(true, cacheSize);
}
public CobarClientInternalRouter(boolean enableCache, int cacheSize) {
this.enableCache = enableCache;
if (this.enableCache) {
localCache = new LRUMap(cacheSize);
}
}
private List<Set<IRoutingRule<IBatisRoutingFact, List<String>>>> ruleSequences = new ArrayList<Set<IRoutingRule<IBatisRoutingFact, List<String>>>>();
public RoutingResult doRoute(IBatisRoutingFact routingFact) throws RoutingException {
if (enableCache) {
synchronized (localCache) {
if (localCache.containsKey(routingFact)) {
RoutingResult result = (RoutingResult) localCache.get(routingFact);
logger.info("return routing result:{} from cache for fact:{}", result, routingFact);
return result;
}
}
}
RoutingResult result = new RoutingResult();
result.setResourceIdentities(new ArrayList<String>());
IRoutingRule<IBatisRoutingFact, List<String>> ruleToUse = null;
if (!CollectionUtils.isEmpty(getRuleSequences())) {
for (Set<IRoutingRule<IBatisRoutingFact, List<String>>> ruleSet : getRuleSequences()) {
ruleToUse = searchMatchedRuleAgainst(ruleSet, routingFact);
if (ruleToUse != null) {
break;
}
}
}
if (ruleToUse != null) {
logger.info("matched with rule:{} with fact:{}", ruleToUse, routingFact);
result.getResourceIdentities().addAll(ruleToUse.action());
} else {
logger.info("No matched rule found for routing fact:{}", routingFact);
}
if (enableCache) {
synchronized (localCache) {
localCache.put(routingFact, result);
}
}
return result;
}
private IRoutingRule<IBatisRoutingFact, List<String>> searchMatchedRuleAgainst(
Set<IRoutingRule<IBatisRoutingFact, List<String>>> rules,
IBatisRoutingFact routingFact) {
if (CollectionUtils.isEmpty(rules)) {
return null;
}
for (IRoutingRule<IBatisRoutingFact, List<String>> rule : rules) {
if (rule.isDefinedAt(routingFact)) {
return rule;
}
}
return null;
}
public LRUMap getLocalCache() {
return localCache;
}
public synchronized void clearLocalCache(){
this.localCache.clear();
}
public boolean isEnableCache() {
return enableCache;
}
public void setRuleSequences(List<Set<IRoutingRule<IBatisRoutingFact, List<String>>>> ruleSequences) {
this.ruleSequences = ruleSequences;
}
public List<Set<IRoutingRule<IBatisRoutingFact, List<String>>>> getRuleSequences() {
return ruleSequences;
}
}