Grid displaying many different objects

[danieljamesscott]

I have a GXT2 project which displays database query results in a grid. The grid displays DBRow objects which extend BaseModelData. The columns within each row are stored as properties of the BaseModel and accessed using e.g. get("name") and set("name").

The user submits a query to the DB and the results are returned. There's a DBRowHeader object which contains the information required to setup the ColumnConfig objects and the List of DBRow objects containing the data.

In GXT3, I understand that there's the new ValueProvider which requires named properties for each model. This is no good for my use case because I would have to write a new model for each model that can be returned.

Is there a way to implement the old system using the new GXT3 grid object?

[Colin Alworth]

Why not make a model that wraps a Map from String keys to Object values? Or, if the values are always the same type, no need to refer to them as Object. Or make the model just Map<String, Object>?

The ValueProvider is just an interface - you can make a ValueProvider any way you want, including one that takes a string and uses that to ask the model for an object. This would act on a Map:

class MapValueProvider implements ValueProvider<Map<String, String>, String> {
  private final String key;
  public MapValueProvider(String key) {
    this.key = key;
  }
  public String getValue(Map<String, String> object) {
    return object.get(key);
  }
  public void setValue(Map<String, String> object, String value) {
    object.put(key, value);
  }
  public String getPath() {
    return key;
  }
}

This could be reused whenever you are reading data from a map. It would need to be adapted of course for a model object that wraps a map, but those changes should be clear.

This could be used like this when making columnConfig instances:

new ColumnConfig<Map<String, String>, String>(new MapValueProvider("name"), ...);

[danieljamesscott]

Excellent thanks. That works.