Analyze MS-Project files - calculate delay from original plan

Main.java

import net.sf.mpxj.MPXJException;
import net.sf.mpxj.ProjectFile;
import net.sf.mpxj.Task;
import net.sf.mpxj.mpp.MPPReader;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.*;
import java.util.logging.*;

public class Main {

    private static final Logger LOG = Logger.getLogger(Main.class.getName());
    private static final long MS_TO_DAYS = 1000 * 60 * 60 * 24;

    public static void main(String[] args) throws MPXJException, IOException {

        Map<String, List<Task>> taskNameToTasks = new HashMap<>();
        MPPReader reader = new MPPReader();
        Files.find(Paths.get("."), 1, (f, a) -> f.toString().endsWith(".mpp"))
                .forEach(f -> {
                    try {
                        LOG.info("Reading " + f);
                        ProjectFile projectFile = reader.read(f.toFile());
                        projectFile.getAllTasks().stream().forEach(t -> collectTask(t, taskNameToTasks));
                    } catch (MPXJException e) {
                        throw new RuntimeException(e);
                    }
                });

        Map<String, Long> taskNameToDelay = new HashMap<>();
        taskNameToTasks.forEach((name, tasks) -> taskNameToDelay.put(name, computeMaxDistance(tasks)));

        LOG.info("Tasks with no matching: " + taskNameToTasks.values().stream().filter(l -> l.size() == 1).count());
        LOG.info("Tasks with matching: " + taskNameToTasks.values().stream().filter(l -> l.size() > 1).count());
        LOG.info("Moving tasks: " + taskNameToDelay.values().stream().filter(d -> d > 0).count());

        Long maxDelayDays = taskNameToDelay.values().stream().sorted().reduce(0L, Math::max);
        LOG.info("Maximum delay (days): " + maxDelayDays);

        String maxDelayTaskName = taskNameToDelay.keySet().stream().filter(name -> maxDelayDays.equals(taskNameToDelay.get(name))).findAny().get();
        LOG.info("Task with maximum delay: " + maxDelayTaskName);

        Task maxDelayTask = taskNameToTasks.get(maxDelayTaskName).get(0);
        List<Task> parentTasks = getParentTasks(maxDelayTask);
        LOG.info("Task in hierarchy:\n" + parentTasks);

        LOG.info("Average delay: " + taskNameToDelay.values().stream().reduce(0L, (a, b) -> a + b) / taskNameToDelay.size());
    }

    /**
     * @return list of tasks leading to given task. Top level first.
     */
    private static List<Task> getParentTasks(Task task) {
        List<Task> result = new ArrayList<>();
        while (task != null) {
            result.add(0, task);
            task = task.getParentTask();
        }
        return result;
    }

    private static long computeMaxDistance(List<Task> tasks) {
        long max = 0;
        for (Task task1 : tasks) {
            for (Task task2 : tasks) {
                Date finish1 = task1.getFinish();
                Date finish2 = task2.getFinish();
                max = Math.max(daysDifference(finish1, finish2), max);
            }
        }
        return max;
    }

    private static long daysDifference(Date finish1, Date finish2) {
        return Math.abs((finish1.getTime() - finish2.getTime()) / MS_TO_DAYS);
    }

    private static void collectTask(Task t, Map<String, List<Task>> taskNameToTasks) {
        // use uniqueId, as tasks with the same name might be used in several places
        String id = t.getUniqueID() + t.getName().trim();
        if (!taskNameToTasks.containsKey(id)) {
            taskNameToTasks.put(id, new ArrayList<>());
        }
        taskNameToTasks.get(id).add(t);
    }


}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.analyse_msproject</groupId>
    <artifactId>analyse_msproject</artifactId>
    <version>1.0-SNAPSHOT</version>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>


    <dependencies>
        <dependency>
            <groupId>net.sf.mpxj</groupId>
            <artifactId>mpxj</artifactId>
            <version>5.1.13</version>
        </dependency>
    </dependencies>
</project>