exec.examples.EventExamples.java Source code

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/**
 * Copyright 2016 Technische Universitt Darmstadt
 * 
 * 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.
 */
package exec.examples;

import java.io.File;
import java.util.List;

import org.apache.commons.io.FileUtils;

import com.google.common.collect.Lists;

import cc.kave.commons.model.events.CommandEvent;
import cc.kave.commons.model.events.IIDEEvent;
import cc.kave.commons.utils.json.JsonUtils;
import cc.recommenders.io.ReadingArchive;

/**
 * This class contains several code examples that explain how to read enriched
 * event streams with the CARET platform. It cannot be run, the code snippets
 * serve as documentation.
 */
public class EventExamples {

    /**
     * this variable should point to a folder that contains a bunch of .zip
     * files that may be nested in subfolders. If you have downloaded the event
     * dataset from our website, please unzip the archive and point to the
     * containing folder here.
     */
    private static final String DIR_USERDATA = "/Users/seb/Downloads/All-Clean/";

    /**
     * 1: Find all users in the dataset.
     */
    public static List<String> findAllUsers() {
        // This step is straight forward, as events are grouped by user. Each
        // .zip file in the dataset corresponds to one user.

        List<String> zips = Lists.newLinkedList();
        for (File f : FileUtils.listFiles(new File(DIR_USERDATA), new String[] { "zip" }, true)) {
            zips.add(f.getAbsolutePath());
        }
        return zips;
    }

    /**
     * 2: Reading events
     */
    public static void readAllEvents() {
        // each .zip file corresponds to a user
        List<String> userZips = findAllUsers();

        for (String user : userZips) {
            // you can use our helper to open a file...
            ReadingArchive ra = new ReadingArchive(new File(user));
            // ...iterate over it...
            while (ra.hasNext()) {
                // ... and desrialize the IDE event.
                IIDEEvent e = ra.getNext(IIDEEvent.class);
                // afterwards, you can process it as a Java object
                process(e);
            }
            ra.close();
        }
    }

    /**
     * 3: Reading the plain JSON representation
     */
    public static void readPlainEvents() {
        // the example is basically the same as before, but...
        List<String> userZips = findAllUsers();

        for (String user : userZips) {
            ReadingArchive ra = new ReadingArchive(new File(user));
            while (ra.hasNext()) {
                // ... sometimes it is easier to just read the JSON...
                String json = ra.getNextPlain();
                // .. and call the deserializer yourself.
                IIDEEvent e = JsonUtils.fromJson(json, IIDEEvent.class);
                process(e);

                // Not all event bindings are very stable already, reading the
                // JSON helps debugging possible bugs in the bindings
            }
            ra.close();
        }
    }

    /**
     * 4: Processing events
     */
    private static void process(IIDEEvent event) {
        // once you have access to the instantiated event you can dispatch the
        // type. As the events are not nested, we did not implement the visitor
        // pattern, but resorted to instanceof checks.
        if (event instanceof CommandEvent) {
            // if the correct type is identified, you can cast it...
            CommandEvent ce = (CommandEvent) event;
            // ...and access the special context for this kind of event
            System.out.println(ce.CommandId);
        } else {
            // there a many different event types to process, it is recommended
            // that you browse the package to see all types and consult the
            // website for the documentation of the semantics of each event...
        }
    }
}