org.apache.fluo.core.observer.v1.ObserversV1.java Source code

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Here is the source code for org.apache.fluo.core.observer.v1.ObserversV1.java

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/*
 * 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.fluo.core.observer.v1;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import com.google.common.collect.Iterables;
import org.apache.fluo.api.data.Column;
import org.apache.fluo.api.observer.Observer;
import org.apache.fluo.core.impl.Environment;
import org.apache.fluo.core.observer.Observers;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@SuppressWarnings("deprecation")
class ObserversV1 implements Observers {

    private static final Logger log = LoggerFactory.getLogger(ObserversV1.class);

    private Environment env;
    Map<Column, List<Observer>> observers = new HashMap<>();
    Map<Column, org.apache.fluo.api.config.ObserverSpecification> strongObservers;
    Map<Column, org.apache.fluo.api.config.ObserverSpecification> weakObservers;
    Map<Column, String> aliases;

    private List<Observer> getObserverList(Column col) {
        List<Observer> observerList;
        synchronized (observers) {
            observerList = observers.get(col);
            if (observerList == null) {
                observerList = new ArrayList<>();
                observers.put(col, observerList);
            }
        }
        return observerList;
    }

    public ObserversV1(Environment env,
            Map<Column, org.apache.fluo.api.config.ObserverSpecification> strongObservers,
            Map<Column, org.apache.fluo.api.config.ObserverSpecification> weakObservers) {
        this.env = env;
        this.strongObservers = strongObservers;
        this.weakObservers = weakObservers;
        this.aliases = new HashMap<>();

        for (Entry<Column, org.apache.fluo.api.config.ObserverSpecification> e : Iterables
                .concat(strongObservers.entrySet(), weakObservers.entrySet())) {
            org.apache.fluo.api.config.ObserverSpecification observerConfig = e.getValue();
            try {
                String alias = Class.forName(observerConfig.getClassName()).asSubclass(Observer.class)
                        .getSimpleName();
                aliases.put(e.getKey(), alias);
            } catch (ClassNotFoundException e1) {
                throw new RuntimeException(e1);
            }
        }
    }

    @Override
    public Observer getObserver(Column col) {

        List<Observer> observerList;
        observerList = getObserverList(col);

        synchronized (observerList) {
            if (observerList.size() > 0) {
                return observerList.remove(observerList.size() - 1);
            }
        }

        Observer observer = null;

        org.apache.fluo.api.config.ObserverSpecification observerConfig = strongObservers.get(col);
        if (observerConfig == null) {
            observerConfig = weakObservers.get(col);
        }

        if (observerConfig != null) {
            try {
                observer = Class.forName(observerConfig.getClassName()).asSubclass(Observer.class).newInstance();
                observer.init(new ObserverContext(env, observerConfig.getConfiguration()));
            } catch (RuntimeException e) {
                throw e;
            } catch (Exception e) {
                throw new RuntimeException(e);
            }

            if (!observer.getObservedColumn().getColumn().equals(col)) {
                throw new IllegalStateException(
                        "Mismatch between configured column and class column " + observerConfig.getClassName() + " "
                                + col + " " + observer.getObservedColumn().getColumn());
            }
        }

        return observer;
    }

    @Override
    public void returnObserver(Observer observer) {
        List<Observer> olist = getObserverList(observer.getObservedColumn().getColumn());
        synchronized (olist) {
            olist.add(observer);
        }
    }

    @Override
    public void close() {
        if (observers == null) {
            return;
        }

        synchronized (observers) {
            for (List<Observer> olist : observers.values()) {
                synchronized (olist) {
                    for (Observer observer : olist) {
                        try {
                            observer.close();
                        } catch (Exception e) {
                            log.error("Failed to close observer", e);
                        }
                    }
                    olist.clear();
                }
            }
        }

        observers = null;
    }

    @Override
    public String getObserverId(Column col) {
        return aliases.get(col);
    }
}