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# ResourceUpdate
An edit to one existing resource in a live project. It goes into `resources.update` of [`SchedulingChanges`](), which [`Project::apply`]() takes. Create it with `ResourceUpdate::new` and set only the fields to change. To add a resource, use [`ResourceData`]() in `resources.add` instead.
## Declaration
```rust
#[derive(Clone, Debug)]
pub struct ResourceUpdate {
pub id: Id,
pub capacity: Patch,
pub calendar_id: Patch,
}
```
## Constructors
### ResourceUpdate::new
```rust
pub fn new(id: impl Into) -> ResourceUpdate
```
Creates an update for the resource `id` with every field set to [`Patch::Missing`](), so nothing changes until a field is set.
**Parameters**
| Name | Type | Description |
|---|---|---|
| `id` | `impl Into<`[`Id`]()`>` | Id of the resource to edit. Accepts a string or a number. |
**Returns** a `ResourceUpdate` that leaves the resource unchanged.
## Fields
Each `Patch` field follows the [`Patch`]() rules: `Missing` leaves the field as is, `Null` clears it, `Value` sets it. The new value is validated like the matching [`ResourceData`]() field.
### id
```rust
pub id: Id
```
[`Id`]() of the resource to edit. It must name a resource in the project.
### capacity
```rust
pub capacity: Patch
```
New [`ResourceData::capacity`](). `Null` clears it, so the resource takes the default capacity again.
Default: `Patch::Missing`.
### calendar_id
```rust
pub calendar_id: Patch
```
New [`ResourceData::calendar_id`](). `Null` clears it, so the resource has no calendar of its own. The id must name an existing calendar; [`Project::apply`]() can't add calendars.
When assignments work on resource calendars, a task whose working calendars change keeps its start and duration, and its end is derived again. See [Resources and assignments]().
Default: `Patch::Missing`.
## Errors
[`Project::apply`]() rejects the operation, and lists it under its path (such as `resources.update[0]`) in [`ApplyReport::rejected`](), when:
- `id` names no resource in the project (`unknown resource id`)
- the new `capacity` or `calendar_id` fails [`ResourceData` validation]()
A rejected update leaves the resource unchanged.
## Example
```rust
use plen_core::{
Patch, Project, ProjectData, ProjectOptions, ResourceData, ResourceUpdate,
SchedulingChanges, SolveOptions,
};
fn main() -> Result<(), Box> {
let mut project = Project::new(ProjectOptions::default());
let data = ProjectData {
resources: vec![ResourceData {
id: "team".into(),
capacity: Some(1.0),
calendar_id: None,
}],
..Default::default()
};
project.solve(Some(data), &SolveOptions::default())?;
let mut update = ResourceUpdate::new("team");
update.capacity = Patch::Value(2.0);
let mut changes = SchedulingChanges::default();
changes.resources.update.push(update);
let report = project.apply(&changes)?;
println!("rejected: {:?}", report.rejected);
Ok(())
}
```
## Related
- [`ResourceData`]() - the record an update edits
- [`Patch`]() - the type of every editable field
- [`ApplyReport`]() - reports whether the update was applied
- [Data Updates]() - shows resource updates in a change set