customize toString() on enums

[Rizen59]

Hi,

With the ToString plugin, classes implements ToString but not enums.
With the EnumValue plugin, enums can EnumValue.

Maybe I didn't find how to do, but is it possible to customize the toString method of enums? For exemple to use a resourceBundle.

Best regards,

[laurentschoelens]

Hi @Rizen59
You can follow the wiki page of the toString plugin

You can extends the default strategy with custom implementation for EnumValue with the -XtoString-toStringStrategyClass=com.acme.foo.MyToStringStrategy argument

[laurentschoelens]

Or maybe I misunderstood your problem. Could you provide a MRE ?
You said that the toString plugin was not applied to Enum generated with EnumValue plugin, is that right ?

[Rizen59]

Hi Laurent,

Firstly thanks for your quick answer!
I pushed a sample to demonstrate the situation here: https://github.com/Rizen59/jaxb-tostring

If you generate the model you'll see that objects Console / Consoles / Devices implements ToString and override the methods to use the strategy I defined. But not Model and Vendor.

What I tried to do was override the toString also in enums, to be able to use the resource bundles into (provided also in the sample project).

Also I was wondering something :

• with mvn jaxb:generate the model is generated but the objects does not implement ToString
• with mvn install it is

Is it normal?

[laurentschoelens]

Thanks for the example. I'll take a look soon.

For the other question, it depends of your build config but it's normal mvn behavor. See comment here

[Rizen59]

Thanks for your feedback.
Maybe I'm not familiar enough with the maven build process but it would be convenient that the model generation apply also the jaxb-plugins. I will not check that for the moment, it was just an observation.

About the toString an enum I found an old issue with the same question: highsource/jaxb2-basics#31
At that time the response was to not add a ToString on enums but manage it directly in the strategy.
But how the strategy could be called if the enum does not implement it?

[laurentschoelens]

I've seen your configuration and that's what I've said for the jaxb:generate part.
You've defined an execution with no id (so defaults to default) with the configuration inside
The jaxb:generate will bind to jaxb-maven-plugin with generate goal on default-cli execution (internal mvn stuff).
So the configuration in your default-execution won't be picked up by this specific goal.

Since here you don't use more than 1 execution, you should bring the configuration at plugin level like this :

<plugin>
    <groupId>org.jvnet.jaxb</groupId>
    <artifactId>jaxb-maven-plugin</artifactId>
    <version>${jaxb.plugin.version}</version>
    <executions>
        <execution>
            <goals>
                <goal>generate</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <noFileHeader>true</noFileHeader>
        <extension>true</extension>
        <locale>en</locale>
        <args>
            <arg>-XenumValue</arg>
            <arg>-XtoString</arg>
            <arg>-XtoString-toStringStrategyClass=test.jaxb.EnumToStringStrategy</arg>
        </args>
        <plugins>
            <plugin>
                <groupId>org.jvnet.jaxb</groupId>
                <artifactId>jaxb-plugins</artifactId>
                <version>${jaxb.plugin.version}</version>
            </plugin>
        </plugins>
    </configuration>
</plugin>

[laurentschoelens]

For the toString question, the original answer was to add the following method in your custom strategy :

    public StringBuilder append(ObjectLocator locator,
                                StringBuilder buffer,
                                Object value) {

        if (value instanceof EnumValue<?>) {
            // do your stuff here of calling the resource bundle to get actual wanted displayed value
            return super.append(locator, buffer,
                    ((EnumValue<?>) value).enumValue());
        } else {
            return super.append(locator, buffer, value);
        }
    }

This only works if you don't call the toString on the enum class but on the model object (like in the Console object, it'll be called in the following block generated by the -XtoString plugin) :

        {
            Model theModel;
            theModel = this.getModel();
            strategy.appendField(locator, this, "model", buffer, theModel, (this.model!= null));
        }

Will it be enough for your use case ?

[Rizen59]

No really because I wanted to call toString directly from the enum :/

Thanks your previous answer on the configuration!

[laurentschoelens]

OK so my guess is to take back original PR submission in 2015 and adapt it to jaxb-tools latest version

I'll push a PR according to this.