org.pascani.dsl.lib.infrastructure.NamespaceProxy.java Source code

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Here is the source code for org.pascani.dsl.lib.infrastructure.NamespaceProxy.java

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/*
 * Copyright  2015 Universidad Icesi
 * 
 * This file is part of the Pascani project.
 * 
 * The Pascani project is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 * 
 * The Pascani project is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
 * for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with The Pascani project. If not, see <http://www.gnu.org/licenses/>.
 */
package org.pascani.dsl.lib.infrastructure;

import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.lang3.SerializationUtils;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.pascani.dsl.lib.PascaniRuntime;
import org.pascani.dsl.lib.infrastructure.rabbitmq.RabbitMQRpcClient;
import org.pascani.dsl.lib.util.SerializationUtils6;

/**
 * @author Miguel Jimnez - Initial contribution and API
 */
public class NamespaceProxy implements Namespace {

    /**
     * The logger
     */
    protected final Logger logger = LogManager.getLogger(NamespaceProxy.class);

    /**
     * An RPC client configured to make requests to a specific {@link Namespace}
     */
    private final RpcClient client;

    /**
     * Creates a NamespaceProxy instance from a routing key, and the default RPC
     * exchange
     * 
     * @param routingKey
     *            The namespace's routing key
     * 
     * @throws Exception
     */
    public NamespaceProxy(String routingKey) throws Exception {
        this(new RabbitMQRpcClient(PascaniRuntime.getEnvironment().get("rpc_exchange"), routingKey));
    }

    /**
     * @param client
     *            An already configured RPC client, i.e., an initialized client
     *            that knows a routing key
     */
    public NamespaceProxy(RpcClient client) {
        this.client = client;
    }

    /**
     * Performs an RPC call to a remote namespace
     * 
     * @param message
     *            The payload of the message
     * @param defaultValue
     *            A decent value to nicely return in case an {@link Exception}
     *            is thrown
     * @return The response from the RPC server (i.e., a remote component
     *         processing RPC requests) configured with the routing key of the
     *         {@link RpcClient} instance
     */
    private byte[] makeActualCall(RpcRequest request, Serializable defaultValue) {
        byte[] message = SerializationUtils.serialize(request);
        byte[] response = SerializationUtils.serialize(defaultValue);
        try {
            response = client.makeRequest(message);
        } catch (Exception e) {
            this.logger.error("Error performing an RPC call to namespace " + this.client.routingKey(),
                    e.getCause());
            throw new RuntimeException(e);
        }
        return response;
    }

    /*
     * (non-Javadoc)
     * 
     * @see pascani.lang.infrastructure.Namespace#getVariable(java.lang.String)
     */
    public Serializable getVariable(String variable) {
        RpcRequest request = new RpcRequest(RpcOperation.NAMESPACE_GET_VARIABLE, variable);
        byte[] response = makeActualCall(request, null);
        return (Serializable) SerializationUtils6.deserialize(response);
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.pascani.dsl.lib.infrastructure.Namespace#getVariable(java.lang.
     * String, java.util.Map)
     */
    public Serializable getVariable(String variable, Map<String, String> tags) {
        HashMap<String, String> serializableMap = new HashMap<String, String>(tags);
        RpcRequest request = new RpcRequest(RpcOperation.NAMESPACE_GET_VARIABLE, variable, serializableMap);
        byte[] response = makeActualCall(request, null);
        return (Serializable) SerializationUtils6.deserialize(response);
    }

    /*
     * (non-Javadoc)
     * 
     * @see pascani.lang.infrastructure.Namespace#setVariable(java.lang.String,
     * java.io.Serializable)
     */
    public Serializable setVariable(String variable, Serializable value) {
        RpcRequest request = new RpcRequest(RpcOperation.NAMESPACE_SET_VARIABLE, variable, value);
        byte[] response = makeActualCall(request, null);
        return SerializationUtils.deserialize(response);
    }

    /*
     * (non-Javadoc)
     * 
     * @see pascani.lang.util.Resumable#pause()
     */
    public void pause() {
        RpcRequest request = new RpcRequest(RpcOperation.PAUSE);
        makeActualCall(request, false); // true should be returned
    }

    /*
     * (non-Javadoc)
     * 
     * @see pascani.lang.util.Resumable#resume()
     */
    public void resume() {
        RpcRequest request = new RpcRequest(RpcOperation.RESUME);
        makeActualCall(request, false); // true should be returned
    }

    /*
     * (non-Javadoc)
     * 
     * @see pascani.lang.util.Resumable#isPaused()
     */
    public boolean isPaused() {
        RpcRequest request = new RpcRequest(RpcOperation.PAUSE);
        byte[] response = makeActualCall(request, false);
        return (Boolean) SerializationUtils6.deserialize(response);
    }

    /**
     * Shutdowns connections
     * 
     * @throws Exception
     *             If something bad happens!
     */
    public void shutdown() throws Exception {
        this.client.shutdown();
    }

}