dubbo-cluster/src/main/java/org/apache/dubbo/rpc/cluster/router/mock/MockInvokersSelector.java

/*
 * 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.
 */
package org.apache.dubbo.rpc.cluster.router.mock;

import org.apache.dubbo.common.URL;
import org.apache.dubbo.common.utils.CollectionUtils;
import org.apache.dubbo.rpc.Invocation;
import org.apache.dubbo.rpc.Invoker;
import org.apache.dubbo.rpc.RpcException;
import org.apache.dubbo.rpc.cluster.router.state.AbstractStateRouter;
import org.apache.dubbo.rpc.cluster.router.state.BitList;
import org.apache.dubbo.rpc.cluster.router.state.StateRouterResult;

import static org.apache.dubbo.rpc.cluster.Constants.INVOCATION_NEED_MOCK;
import static org.apache.dubbo.rpc.cluster.Constants.MOCK_PROTOCOL;

/**
 * A specific Router designed to realize mock feature.
 * If a request is configured to use mock, then this router guarantees that only the invokers with protocol MOCK appear in final the invoker list, all other invokers will be excluded.
 */
public class MockInvokersSelector<T> extends AbstractStateRouter<T> {

    public static final String NAME = "MOCK_ROUTER";
    private static final int MOCK_INVOKERS_DEFAULT_PRIORITY = -100;

    private volatile BitList<Invoker<T>> normalInvokers = BitList.emptyList();
    private volatile BitList<Invoker<T>> mockedInvokers = BitList.emptyList();

    public MockInvokersSelector(URL url) {
        super(url);
        this.setPriority(MOCK_INVOKERS_DEFAULT_PRIORITY);
    }

    @Override
    public StateRouterResult<Invoker<T>> route(BitList<Invoker<T>> invokers, URL url,
                                                   Invocation invocation, boolean needToPrintMessage) throws RpcException {
        if (CollectionUtils.isEmpty(invokers)) {
            return new StateRouterResult<>(invokers,
                needToPrintMessage ? "Empty invokers. Directly return." : null);
        }

        if (invocation.getObjectAttachments() == null) {
            return new StateRouterResult<>(invokers.and(normalInvokers),
                needToPrintMessage ? "ObjectAttachments from invocation are null. Return normal Invokers." : null);
        } else {
            String value = (String) invocation.getObjectAttachments().get(INVOCATION_NEED_MOCK);
            if (value == null) {
                return new StateRouterResult<>(invokers.and(normalInvokers),
                    needToPrintMessage ? "invocation.need.mock not set. Return normal Invokers." : null);
            } else if (Boolean.TRUE.toString().equalsIgnoreCase(value)) {
                return new StateRouterResult<>(invokers.and(mockedInvokers),
                    needToPrintMessage ? "invocation.need.mock is true. Return mocked Invokers." : null);
            }
        }
        return new StateRouterResult<>(invokers,
            needToPrintMessage ? "Directly Return. Reason: invocation.need.mock is set but not match true" : null);
    }

    @Override
    public void notify(BitList<Invoker<T>> invokers) {
        cacheMockedInvokers(invokers);
        cacheNormalInvokers(invokers);
    }

    private void cacheMockedInvokers(BitList<Invoker<T>> invokers) {
        BitList<Invoker<T>> clonedInvokers = invokers.clone();
        clonedInvokers.removeIf((invoker) -> !invoker.getUrl().getProtocol().equals(MOCK_PROTOCOL));
        mockedInvokers = clonedInvokers;
    }

    @SuppressWarnings("rawtypes")
    private void cacheNormalInvokers(BitList<Invoker<T>> invokers) {
        BitList<Invoker<T>> clonedInvokers = invokers.clone();
        clonedInvokers.removeIf((invoker) -> invoker.getUrl().getProtocol().equals(MOCK_PROTOCOL));
        normalInvokers = clonedInvokers;
    }

}