[Canonical page](<https://docs.dhtmlx.com/planning-engine/java/how-to/accept-messy-input/>)
[Full documentation index](<https://docs.dhtmlx.com/planning-engine/llms.txt>)


# Accept messy input

Schedule project data that strict validation rejects, such as data with duplicate ids or missing dates, and get a list of every fix the engine made.

By default a [`Project`](<https://docs.dhtmlx.com/planning-engine/java/api/project/project.md>) uses [`Validation.STRICT`](<https://docs.dhtmlx.com/planning-engine/java/api/project/validation.md>) and throws [`InputException`](<https://docs.dhtmlx.com/planning-engine/java/api/errors/input-exception.md>) for the first invalid field. `Validation.REPAIR` coerces the data into valid input instead, then schedules the result.

## Steps

1. Create the project with repair validation:

   ```java
   var project = new Project(new ProjectOptions().withValidation(Validation.REPAIR));
   ```

2. Pass your data to [`Project#solve`](<https://docs.dhtmlx.com/planning-engine/java/api/project-solve.md>) as usual. [`Project#analyze`](<https://docs.dhtmlx.com/planning-engine/java/api/project-analyze.md>) with non-null data repairs it the same way. [`Engine.schedule`](<https://docs.dhtmlx.com/planning-engine/java/api/engine-schedule.md>) always uses strict validation, so use a `Project` here.

3. Read the [`Note.Repaired`](<https://docs.dhtmlx.com/planning-engine/java/api/results/note.md#repaired>) entries in `result.notes` and show them to the user, or log them. Each one has a `path` and a `message`.

The full example below has four kinds of problems: a duplicate id, a task with no dates, a dated constraint with no date, and a task whose start, end and duration disagree. Strict validation rejects this data. Repair schedules it:

```java
import java.util.List;
import org.dhtmlx.plen.*;

public class AcceptMessyInput {
  public static void main(String[] args) throws Exception {
    var jan1 = Moment.fromYmdHm(2026, 1, 1, 0, 0);
    var jan4 = Moment.fromYmdHm(2026, 1, 4, 0, 0);

    // Start and end without a duration: valid, nothing to repair.
    var design = new TaskData(Id.str("design")).withStartDate(jan1).withEndDate(jan4);

    // "build" appears twice. The later record wins.
    var buildOld = new TaskData(Id.str("build")).withStartDate(jan1).withDuration(1.0);
    var build = new TaskData(Id.str("build")).withStartDate(jan1).withDuration(2.0);

    // No dates, no duration, and a dated constraint without a constraint date.
    var review = new TaskData(Id.str("review")).withConstraintType(ConstraintType.SNET);

    // Three days between start and end, but the duration says five.
    var deploy = new TaskData(Id.str("deploy"))
        .withStartDate(jan1)
        .withEndDate(jan4)
        .withDuration(5.0);

    var data = new ProjectData()
        .withTasks(List.of(design, buildOld, review, build, deploy));
    // 24/7 time keeps the example dates easy to check.
    data.config.useCalendars = false;

    var project = new Project(new ProjectOptions().withValidation(Validation.REPAIR));
    var options = new SolveOptions().withIncludeUnchanged(true);
    var result = project.solve(data, options);

    for (var note : result.notes) {
      if (note instanceof Note.Repaired r) {
        System.out.println(r.path + ": " + r.message);
      }
    }
    for (var m : result.updates) {
      System.out.println(m.id + " " + m.startDate + ".." + m.endDate + " " + m.duration);
    }
  }
}
```

## What repair changes

Repair reports each change below as one [`Note.Repaired`](<https://docs.dhtmlx.com/planning-engine/java/api/results/note.md#repaired>), with the field path in `path`:

- Duplicate ids in `tasks`, `links`, `resources`, `assignments` and `calendars`: the last record replaces the earlier one and takes its position. The note is at `tasks[i].id`, where `i` is the index of the duplicate in your input.
- A task with no start and no end gets `startDate` set to `config.projectStart`, or to the earliest date of any task if `projectStart` isn't set.
- A leaf task (not a milestone) with no `duration` and only one date gets `duration` 1.
- Start, end and duration that disagree: the dates win, and the duration becomes the working time between them. If the end is in non-working time, or the dates were computed on a different calendar, repair drops the duration and resolves the task from its dates. An end that falls inside a pause moves to the pause start, with a second note at `tasks[i].end_date`.
- A summary with only one date gets the other date computed from that date and its duration.
- A dated constraint (`SNET`, `SNLT`, `FNET`, `FNLT`, `MSO`, `MFO`) without `constraintDate` is cleared.
- Invalid `pauses` on a task: the whole list is cleared, with a note at `tasks[i].pauses`.
- An invalid assignment `offset` or `duration` is cleared, so the assignment books the whole task.

A task that already has two of start, end and duration is valid input. Repair doesn't touch it and doesn't report it.

Note paths use the JSON field names (`start_date`, `constraint_type`), not the Java field names.

Only the duplicate-id notes use input indexes. Every other note indexes the deduplicated list. In the example, the two `build` records become one, so `deploy` is `tasks[4]` in your input but `tasks[3]` in its note.

Repair works on the project's own copy of the data. The [`ProjectData`](<https://docs.dhtmlx.com/planning-engine/java/api/data/project-data.md>) you pass in isn't changed.

## What repair doesn't fix

- An entirely undated project, with no `config.projectStart` and no task that has a date, still throws [`InputException`](<https://docs.dhtmlx.com/planning-engine/java/api/errors/input-exception.md>) at `tasks[i].start_date`. The engine never falls back to today's date.
- Every other invalid input, such as a cycle in the `parent` hierarchy or a calendar with no working time, still throws `InputException`. See [Error handling](<https://docs.dhtmlx.com/planning-engine/java/error-handling.md>).
- If repair or validation fails, [`solve`](<https://docs.dhtmlx.com/planning-engine/java/api/project-solve.md>) throws and the project keeps its previous state.

## Result

The example prints the fixes, then the scheduled dates (the date lines may come in a different order):

```text
tasks[3].id: duplicate id replaced the earlier record, retaining its position
tasks[2].constraint_type: dated constraint without date cleared
tasks[2].start_date: missing date defaulted to project anchor
tasks[2].duration: missing duration defaulted to one
tasks[3].duration: duration recomputed from supplied start and end
design 2026-01-01 00:00..2026-01-04 00:00 3.0
build 2026-01-01 00:00..2026-01-03 00:00 2.0
review 2026-01-01 00:00..2026-01-02 00:00 1.0
deploy 2026-01-01 00:00..2026-01-04 00:00 3.0
```

`build` uses the second record's duration of 2, and `deploy` has a duration of 3, taken from its dates. With `new Project()`, the same `solve` call throws `InputException`.