Extending code completion to support internal orm

Question

As said in the tittle, i need to extend code completion to support a internal ORM.

It's something like ActiveRecords. Ex.:

@TableName("ONE_MODEL")
public class OneModel extends BaseModel {

}

...
OneModel oneModel = OneModel.getById(1);
Object value = oneModel.get("COLUMN_NAME");
...

So, when using smart completion when caret between quotation marks inside de .get method, for example, i need to show parameters options based on the table columns.

Something like that it's possible to be made with Intellij Plugins?

I was reading about CompletionContributor, but can't find anything about the possibility to identify the class whose method is being called, it's super class, and it's annotations values.

Answer 1

CompletionContributor is the way to go. This example is taken from the official SDK docs:

public class SimpleCompletionContributor extends CompletionContributor {
  public SimpleCompletionContributor() {
    extend(CompletionType.BASIC,
           PlatformPatterns.psiElement(SimpleTypes.VALUE).withLanguage(SimpleLanguage.INSTANCE),
           new CompletionProvider<CompletionParameters>() {
             public void addCompletions(@NotNull CompletionParameters parameters,
                                        ProcessingContext context,
                                        @NotNull CompletionResultSet resultSet) {
               resultSet.addElement(LookupElementBuilder.create("Hello"));
             }
           }
    );
  }
}

The second parameter of extend allows you to trigger your provider on a specific kind of PSI element. In your case, you could target something like PlatformPatterns.psiElement(JavaElementType.LITERAL_EXPRESSION), then in your CompletionProvider you can check for the exact element with parameters.getPosition() and see if it's a PsiLiteral representing a String.

Using the PSI API, you can then discover what's around this literal, like classes if the containing file is a PsiClassOwner, or with PsiTreeUtil.getParentOfType() etc.

In your specific example, you could check if the string literal is part of a PsiMethodCallExpression.

To easily understand how the PSI tree is built, I highly suggest you open Tools > View PSI Structure... and paste a sample of what you want to detect: