storlets/src/java/SBus/src/main/org/openstack/storlet/sbus/ServerSBusInDatagram.java

/*
 * Copyright (c) 2015, 2016 OpenStack Foundation.
 *
 * Licensed 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.
 */

/*
 * Designating the host side as the client side and the storlet side
 * as the server side, the IPC between the client and server requires
 * 4 different serialization / de-serialization objects:
 * 1. Serializing client commands (client side)
 * 2. De-srializing client commands (server side)
 * 3. Serializing server response (server side)
 * 4. De-srializing server response (client side)
 * This Java class implements the server side serialization objects:
 * ServerSBusInDatagram
 */
package org.openstack.storlet.sbus;

import java.io.FileDescriptor;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
import org.json.simple.JSONObject;
import org.json.simple.JSONArray;

public class ServerSBusInDatagram {

    private int numFDs;
    private FileDescriptor[] fds;
    private String command;
    private HashMap<String, String> params;
    private HashMap<String, HashMap<String, String>>[] metadata;
    private String taskID;

    private void populateMetadata(HashMap<String, String> dest, JSONObject source) throws ParseException {
        for (Object key : source.keySet()) {
            String strKey = (String)key;
            String strVal = (String)source.get(key);
            dest.put(strKey, strVal);
        }
    }

    /**
     * Parses a raw message coming from the wire.
     * The incoming message is constructed by the ClientSBusOutDatagram.
     * The message is structured as follows:
     * Array of file descriptors, already parsed in SBusRawMessage
     * A command related json string of the following structure:
     * {
     *     "command": "command encoded as string",
     *     "params": {                            // This element is optional
     *         "key1": "value1",
     *         ...
     *     },
     *     "task_id": "task id encoded as string" // This element is optional
     * }
     * File descriptors metadata, encoded as a JSON array with one
     * element per file descriptor. The i'th element in the array
     * consists of the metadata of the i'th element in the file
     * descriptors array:
     * [
     *     {
     *         "storlets": {
     *             "type": "the fd type encoded as string",  // Mandatory
     *             ... // Additional optional storlets metadata
     *         },
     *         "storage": {
     *             "metadata key1": "metadata value 1",
     *             ...
     *        }
     *     },
     *     ...
     * ]
     * All the values in the above JSON elements are strings.
     * Once constructed the class provides all necessary accessors to the parsed
     * fields.
     * @param msg   the raw mwssage consisting of the string encoded json formats
     * @see SBusPythonFacade.ClientSBusOutDatagram the python code that serilializes the datagram
     * @see SBusPythonFacade.ServerSBusInDatagram the equivalent python code
     */
    public ServerSBusInDatagram(final SBusRawMessage msg) throws ParseException {
        this.fds = msg.getFiles();
                numFDs = this.fds == null ? 0 : this.fds.length;

        JSONObject jsonCmdParams = (JSONObject)(new JSONParser().parse(msg.getParams()));
        this.command = (String)jsonCmdParams.get("command");
        this.params = new HashMap<String, String>();
        if (jsonCmdParams.containsKey("params")) {
            JSONObject jsonParams = (JSONObject)jsonCmdParams.get("params");
            for (Object key : jsonParams.keySet()) {
                this.params.put((String)key, (String)jsonParams.get(key));
            }
        }
        if (jsonCmdParams.containsKey("task_id")) {
            this.taskID = (String)jsonCmdParams.get("task_id");
        }

        String strMD = msg.getMetadata();
        this.metadata = (HashMap<String, HashMap<String, String>>[])new HashMap[getNFiles()];
        JSONArray jsonarray = (JSONArray)(new JSONParser().parse(strMD));
        Iterator<JSONObject> it = jsonarray.iterator();
        int i=0;
        while (it.hasNext()) {
            this.metadata[i] = new HashMap<String, HashMap<String, String>>();
            HashMap<String, String> storletsMetadata = new HashMap<String, String>();
            HashMap<String, String> storageMetadata = new HashMap<String, String>();
            JSONObject jsonobject = it.next();
            if (jsonobject.containsKey("storage")) {
                populateMetadata(storageMetadata, (JSONObject)jsonobject.get("storage"));
            }
            if (!jsonobject.containsKey("storlets")) {
            }
            else {
                populateMetadata(storletsMetadata, (JSONObject)jsonobject.get("storlets"));
            }
            this.metadata[i].put("storage", storageMetadata);
            this.metadata[i].put("storlets", storletsMetadata);
            i++;
        }
    }

    public FileDescriptor[] getFiles() {
        return fds;
    }

    public int getNFiles() {
        return numFDs;
    }

    public String getCommand() {
        return command;
    }

    public HashMap<String, String> getExecParams() {
        return params;
    }

    public String getTaskId() {
        return taskID;
    }

    public HashMap<String, HashMap<String, String>>[] getFilesMetadata() {
        return metadata;
    }
}