枚举属性文件中的常量显示名称

Question

I have an enum datatype in my EMF model.

This is what I want:

1. I'd like to have nice display names for the enum constants.
2. The display names should be set in a plugin.properties file.
3. The mechanism for must integrate well with the EMF system for getting values from properties, so that I can treat all values, enum or not, in a uniform way. That probably means that the solution must use IItemPropertyDescriptor somehow.

I can see that enum constants get generated entries in my plugin.properties in my EMF Edit project. So there should be some way to get at those names. But I can't figure out how.

I can set the display names in my Xcore model file, but that is not what I want. I want them to be read from my plugin.properties file.

It is simple to manually get the enum display names from the properties file. But there should be some way to make EMF handle this. It seems weird that I should have to write special code to handle enum values each time I get a value from the model.

Answer 1

Here is an example:

public enum Constants {
    PROP1,
    PROP2;

    private static final String PATH            = "/constants.properties";

    private static final Logger logger          = LoggerFactory.getLogger(Constants.class);

    private static Properties   properties;

    private String          value;

    private void init() {
        if (properties == null) {
            properties = new Properties();
            try {
                properties.load(Constants.class.getResourceAsStream(PATH));
            }
            catch (Exception e) {
                logger.error("Unable to load " + PATH + " file from classpath.", e);
                System.exit(1);
            }
        }
        value = (String) properties.get(this.toString());
    }

    public String getValue() {
        if (value == null) {
            init();
        }
        return value;
    }

}

And this can be the constans.properties file:

#This is property file...
PROP1=some text
PROP2=some other text

Answer 2

I have managed to get the enum display values using EMF. But with a sever limitation, so I don't consider this to be solved.

The solution works by calling ItemPropertyDescriptor.getLabelProvider . The returned label provider is an ItemDelegator , which is the only class I have found that has code for reading enum literals from property files. So it's just to call getText on that label provider.

IItemPropertySource adapter = (IItemPropertySource) adapterFactory.adapt(eObject, IItemPropertySource.class);
IItemPropertyDescriptor descriptor = adapter.getPropertyDescriptor(eObject, feature);
Object propertyValue = descriptor.getPropertyValue(eObject);
Object value = ((IItemPropertySource) propertyValue).getEditableValue(null);    
String text descriptor.getLabelProvider(value).getText(value);

The limitation is that ItemDelegator "crops" the returned text, by replacing all text after a newline with ... .

Unfortunately I have to handle multi-line strings in some places in my application, so I still can't handle all features in a uniform way with this solution. So I would really like to find a better one.