Marcosrico commented on code in PR #2343: URL: https://github.com/apache/helix/pull/2343#discussion_r1086002703
########## meta-client/src/main/java/org/apache/helix/metaclient/impl/zk/util/ZkMetaClientUtil.java: ########## @@ -0,0 +1,213 @@ +package org.apache.helix.metaclient.impl.zk.util; + +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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. + */ + +import org.apache.helix.metaclient.api.MetaClientInterface; +import org.apache.helix.metaclient.api.OpResult; +import org.apache.helix.metaclient.constants.*; +import org.apache.helix.zookeeper.zkclient.exception.*; +import org.apache.zookeeper.CreateMode; +import org.apache.zookeeper.KeeperException; +import org.apache.zookeeper.Op; +import org.apache.zookeeper.ZooDefs; +import org.apache.zookeeper.data.ACL; +import org.apache.zookeeper.server.EphemeralType; + +import java.util.Collections; +import java.util.EnumMap; +import java.util.List; +import java.util.Map; +import java.util.ArrayList; +import java.util.HashMap; +import java.util.function.Function; + +public class ZkMetaClientUtil { + //TODO Implement MetaClient ACL + //Default ACL value until metaClient Op has ACL of its own. + private static final List<ACL> DEFAULT_ACL = Collections.unmodifiableList(ZooDefs.Ids.OPEN_ACL_UNSAFE); + + private ZkMetaClientUtil(){ + } + + /** + * Helper function for transactionOp. Converts MetaClient Op's into Zk Ops to execute + * zk transactional support. + * @param ops + * @return + */ + public static List<Op> metaClientOpsToZkOps(Iterable<org.apache.helix.metaclient.api.Op> ops) { + if (getOpMap().isEmpty()) { + initializeOpMap(); + } + + List<Op> zkOps = new ArrayList<>(); + for (org.apache.helix.metaclient.api.Op op : ops) { + Function<org.apache.helix.metaclient.api.Op, Op> function = getOpMap().get(op.getType()); + if (function != null) { + zkOps.add(function.apply(op)); + } else { + throw new IllegalArgumentException("Op type " + op.getType().name() + " is not supported."); + } + } + return zkOps; + } + + private static final class OpMapHolder { + static final Map<org.apache.helix.metaclient.api.Op.Type, Function<org.apache.helix.metaclient.api.Op, Op>> OPMAP = + new EnumMap<>(org.apache.helix.metaclient.api.Op.Type.class); + } + + private static Map<org.apache.helix.metaclient.api.Op.Type, Function<org.apache.helix.metaclient.api.Op, Op>> getOpMap() { + return OpMapHolder.OPMAP; + } + + private static void initializeOpMap() { + getOpMap().put(org.apache.helix.metaclient.api.Op.Type.CREATE, op -> { + try { + CreateMode mode = convertMetaClientMode(((org.apache.helix.metaclient.api.Op.Create) op).getEntryMode()); + return Op.create(op.getPath(), ((org.apache.helix.metaclient.api.Op.Create) op).getData(), DEFAULT_ACL, mode); + } catch (KeeperException e) { + throw translateZkExceptionToMetaclientException(ZkException.create(e)); + } + }); + + getOpMap().put(org.apache.helix.metaclient.api.Op.Type.DELETE, + op -> Op.delete(op.getPath(), ((org.apache.helix.metaclient.api.Op.Delete) op).getVersion())); + + getOpMap().put(org.apache.helix.metaclient.api.Op.Type.SET, + op -> Op.setData(op.getPath(), + ((org.apache.helix.metaclient.api.Op.Set) op).getData(), ((org.apache.helix.metaclient.api.Op.Set) op).getVersion())); + + getOpMap().put(org.apache.helix.metaclient.api.Op.Type.CHECK, + op -> Op.check(op.getPath(), ((org.apache.helix.metaclient.api.Op.Check) op).getVersion())); + } + + private static CreateMode convertMetaClientMode(MetaClientInterface.EntryMode entryMode) throws KeeperException { + switch (entryMode) { + case PERSISTENT: + return CreateMode.PERSISTENT; + case EPHEMERAL: + return CreateMode.EPHEMERAL; + case CONTAINER: + return CreateMode.CONTAINER; + default: + throw new IllegalArgumentException(entryMode.name() + " is not a supported EntryMode."); + } + } + + /** + * Helper function for transactionOP. Converts the result from calling zk transactional support into + * metaclient OpResults. + * @param zkResult + * @return + */ + public static List<OpResult> zkOpResultToMetaClientOpResults(List<org.apache.zookeeper.OpResult> zkResult) { + if (getOpResultMap().isEmpty()) { + initializeOpResultMap(); + } + List<OpResult> metaClientOpResult = new ArrayList<>(); + for (org.apache.zookeeper.OpResult opResult : zkResult) { + Function<org.apache.zookeeper.OpResult, OpResult> function = getOpResultMap().get(opResult.getClass()); + if (function != null) { + metaClientOpResult.add(function.apply(opResult)); + } else { + throw new IllegalArgumentException("OpResult type " + opResult.getType() + "is not supported."); + } + } + + return metaClientOpResult; + } + + private static final class OpResultMapHolder { + static final Map<Class<? extends org.apache.zookeeper.OpResult>, Function<org.apache.zookeeper.OpResult, OpResult>> OPRESULTMAP = + new HashMap<>(); + } Review Comment: Correct me if I am wrong, but I believe what you're saying is to have the map be populated when the static variable `OPRESULTMAP` is declared? I have attempted several methods and none seemed feasible: 1. Create a constructor that invokes `initializeOpResultMap` method when `OpResultMapHolder` object is created. However, given the nature of it being a util class, making it an object is counterproductive. 2. Populating the map directly when declaring the `OPRESULTMAP` static variable instead of having a separate method. This can only be done with java JDK 9+ (current library is at 8) so decided against it. With the current implementation, `initializeOpResultMap` is called just once when needed in the `zkOpResultToMetaClientOpResults` method. Inside, `getOpResultMap` is called first which initializes the `OPRESULTMAP` for the first time, effectively achieving lazy loading. Though ideally when initializing `OPRESULTMAP` for the first time, we would like it to automatically be populated with its values, as mentioned above, I couldn't find a reasonable way to do so. Please suggest a solution that I may have missed. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
