public @Interface BooleanFlag

@BooleanFlag
@Name("example.Rollback")
@Label("Rollback")
@Description("Include transactions that are rollbacked")
public static class RollbackSetting extends SettingControl {
    private static final String DEFAULT_VALUE = "true";
    private boolean value = true;

    @Override
    public String combine(Set<String> values) {
        if (values.contains("true")) {
            return "true";
        }
        if (values.contains("false")) {
            return "false";
        }
        return DEFAULT_VALUE;
    }

    @Override
    public void setValue(String value) {
        // Ignore invalid values
        if ("true".equals(value) || "false".equals(value)) {
            this.value = "true".equals(value);
        }
    }

    @Override
    public String getValue() {
        return Boolean.toString(value);
    }

    public boolean shouldEmit() {
        return value;
    }
}

@Name("example.Transaction")
public static class TransactionEvent extends Event {
    @Label("Context")
    String context;

    @Label("Rollback")
    boolean rollback;

    @SettingDefinition
    @Name("rollback")
    public boolean rollback(RollbackSetting rollbackSetting) {
        return rollback && rollbackSetting.shouldEmit();
    }
}