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/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
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 * Copyright (c) 1997-2018 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://oss.oracle.com/licenses/CDDL+GPL-1.1
 * or LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at LICENSE.txt.
 *
 * GPL Classpath Exception:
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 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
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package org.shoal.adapter.store.commands;

import org.shoal.ha.cache.impl.store.DataStoreEntry;
import org.shoal.ha.cache.api.DataStoreException;
import org.shoal.ha.cache.api.ShoalCacheLoggerConstants;
import org.shoal.ha.cache.impl.command.Command;
import org.shoal.ha.cache.impl.command.ReplicationCommandOpcode;
import org.shoal.ha.cache.impl.util.*;

import java.io.IOException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * @author Mahesh Kannan
 */
public class LoadRequestCommand
        extends Command {

    private static final Logger _logger = Logger.getLogger(ShoalCacheLoggerConstants.CACHE_LOAD_REQUEST_COMMAND);

    private transient CommandResponse resp;

    private transient Future future;

    private long minVersion = -1;

    private long tokenId;

    private String originatingInstance;

    private String target;

    public LoadRequestCommand() {
        super(ReplicationCommandOpcode.LOAD_REQUEST);
    }

    public LoadRequestCommand(K key, long minVersion, String t) {
        this();
        super.setKey(key);
        this.minVersion = minVersion;
        this.target = t;
    }

    protected boolean beforeTransmit() {
        setTargetName(target);
        originatingInstance = dsc.getInstanceName();
        ResponseMediator respMed = dsc.getResponseMediator();
        resp = respMed.createCommandResponse();

        future = resp.getFuture();

        return target != null;
    }

    private void writeObject(java.io.ObjectOutputStream out)
            throws IOException {
        out.writeLong(minVersion);
        out.writeLong(resp.getTokenId());
        out.writeUTF(originatingInstance);
        if (_logger.isLoggable(Level.FINE)) {
            _logger.log(Level.FINE, dsc.getInstanceName() + getName() + " sending load_request command for " + getKey() + "to " + target);
        }
    }

    private void readObject(java.io.ObjectInputStream in)
            throws IOException, ClassNotFoundException {
        minVersion = in.readLong();
        tokenId = in.readLong();
        originatingInstance = in.readUTF();
    }

    @Override
    public void execute(String initiator) {

        try {
            if (_logger.isLoggable(Level.FINE)) {
                _logger.log(Level.FINE, dsc.getInstanceName() + getName() + " received load_request command for " + getKey() + "from " + initiator);
            }
            DataStoreEntry e = dsc.getReplicaStore().getEntry(getKey());

            if (e != null) {
                synchronized (e) {
                    if (!originatingInstance.equals(dsc.getInstanceName())) {
                        LoadResponseCommand rsp = dsc.getDataStoreEntryUpdater().createLoadResponseCommand(e, getKey(), minVersion);
                        rsp.setTokenId(tokenId);
                        rsp.setOriginatingInstance(originatingInstance);

                        getCommandManager().execute(rsp);
                    } else {
                        resp.setResult(dsc.getDataStoreEntryUpdater().getV(e));
                    }
                }
            } else {
                if (!originatingInstance.equals(dsc.getInstanceName())) {
                    LoadResponseCommand rsp = dsc.getDataStoreEntryUpdater().createLoadResponseCommand(null, getKey(), minVersion);
                    rsp.setTokenId(tokenId);
                    rsp.setOriginatingInstance(originatingInstance);

                    getCommandManager().execute(rsp);
                } else {
                    resp.setResult(null);
                }
            }


        } catch (DataStoreException dsEx) {
            resp.setException(dsEx);
        }
    }

    public String getRespondingInstanceName() {
        return resp.getRespondingInstanceName();
    }

    public V getResult(long waitFor, TimeUnit unit)
            throws DataStoreException {
        try {
            Object result = future.get(waitFor, unit);
            if (result instanceof Exception) {
                throw new DataStoreException((Exception) result);
            }
            LoadResponseCommand respCmd = (LoadResponseCommand) result;
            if (respCmd.getVersion() >= minVersion) {
                result = dsc.getDataStoreEntryUpdater().extractVFrom(respCmd);
            } else {
                result = null;
            }
            return (V) result;
        } catch (DataStoreException dsEx) {
            throw dsEx;
        } catch (InterruptedException inEx) {
            _logger.log(Level.WARNING, "LoadRequestCommand Interrupted while waiting for result", inEx);
            throw new DataStoreException(inEx);
        } catch (TimeoutException timeoutEx) {
            _logger.log(Level.WARNING, "LoadRequestCommand timed out while waiting for result " + timeoutEx);
            return null;
        } catch (ExecutionException exeEx) {
            _logger.log(Level.WARNING, "LoadRequestCommand got an exception while waiting for result", exeEx);
            throw new DataStoreException(exeEx);
        }
    }

    public String toString() {
        return getName() + "(" + getKey() + ")";
    }

}