Apply UoM to thing-types.xml : state : min / max / step parameters

AndrewFG · May 2, 2020, 12:19pm

In thing-types.xml one can define certain attributes of a channel-type’s state as follows…

<state min="15" max="30" step="0.5" pattern="%.1f %unit%" readOnly="false"/>

My question is whether it is possible to apply Units of Measurement to the min, max and step parameters of state. So for example for a thermostat target temperature one might define it as follows…

<state min="15|°C" max="30|°C" step="0.5|°C" ... />
.. or ..
<state min="60|°F" max="90|°F" step="1|°F" ... />

rossgb · May 2, 2020, 1:09pm

It doesn’t look like it, those attributes are all parsed as BigDecimal:

github.com

openhab/openhab-core/blob/2.5.0/bundles/org.openhab.core/src/main/java/org/eclipse/smarthome/core/types/StateDescription.java

/**
 * Copyright (c) 2010-2019 Contributors to the openHAB project
 *
 * See the NOTICE file(s) distributed with this work for additional
 * information.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0
 *
 * SPDX-License-Identifier: EPL-2.0
 */
package org.eclipse.smarthome.core.types;

import java.math.BigDecimal;
import java.util.Collections;
import java.util.List;

import org.eclipse.jdt.annotation.NonNullByDefault;
import org.eclipse.jdt.annotation.Nullable;

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AndrewFG · May 2, 2020, 1:20pm

Hi @rossgb many thanks for the response. I guess the answer “no” is clear. However I wonder if it should be added to the “to-do” list, perhaps for OH v3?

rossgb · May 2, 2020, 1:49pm

It’s not a definitive “no”. I don’t have a deep knowledge of the openHAB core, I just did a quick search of the code. There may be another mechanism that you can use to set bounds on a channel-type.

When it comes to UoM it’s probably easiest to just leave the min,max,step stuff to the sitemap/HABPanel level and either do sanity checks in your ThingHandler or let the device/service you are binding do the validation.

AndrewFG · May 2, 2020, 2:23pm

@rossgb yup, that’s what I (my users) have to do now; but it certainly would be good (IMHO) if the developer could provide default values (e.g. min/max/step values in Celsius, and also in Fahrenheit) so the user does not have to think too much about it…

cweitkamp · May 2, 2020, 5:25pm

There is an older issue in ESH repository where a brief discussion was going on about this feature. It tells you something about the issues implementing it and a draft of how it may be designed. I think adding this to the OH3 roadmap is a good idea. It is a nice feature.

AndrewFG · May 2, 2020, 7:51pm

Thanks for the link. I have added a suggestion to that thread.