Execution of a single rule for a group in Drools

I am working on an expert system based on legislation, I have many rules like these:

Rule 1: If the seizure has an amount greater than 3000, seize the amount, justification law 100

Rule 2: If the seizure is of a family type, seize the amount, justification law 200

The problem is that the action "Seize" can only be applied once, but I need to save the history of the rules that are met, I present an example below

rule "law 100"

when 
  $seizure: Seizure(amount>3000)
then
  $seizure.getRules().add("Justification: law 100 of the civil that says bla bla");
  $seizure.applyPunishment();

rule "law 200"

when 
  $seizure: Seizure(type == TYPES.Family)
then
  $seizure.getRules().add("Justification: law 200 of the family code that says bla bla");
  $seizure.applyPunishment();

As I showed above, I need the "then" part that save the description rule "$seizure.getRules().add("Justification: law of the civil code");". and I also need that if the "$seizure.applyPunishment();" was already applied in rule 1, it will not be reapplied in the rule 2.

Thanks in advice

Solution

You have several options here.

Change applyPunishment to be idempotent.

You don't show the code for applyPunishment, but it could look like
```
private boolean alreadySeized = false;

public void applyPunishment() {
    if (alreadySeized) {
        return;
    }

    alreadySeized = true;
```
You could also base this on some other variable that already exists. E.g. if (seizedAmount > 0) return;. But it's hard to say how that might work without the code.

You could change applyPunishment to something like markForPunishment, which could look like

private boolean markedForPunishment;

public void markForPunishment() {
    markedForPunishment = true;
}

Then add a rule like

rule "Punish"

when
  $seizure: Seizure(markedForPunishment  == true)
then
  $seizure.applyPunishment();

With an appropriate getter.

Your other rules would call markForPunishment rather than applyPunishment.

You could use a ruleflow to separate the justifications from the punishment.
You could set a variable in your then clause that you use in your rules.

There are probably other options. The big decision to make is whether you want an MVEL solution or a Java solution. Several of the options will require changing both.