package com.onaro.sanscreen.client.view.tabular.columns;

import org.eclipse.core.runtime.IAdaptable;

import com.onaro.client.swing.table.functional.IFunction;
import com.onaro.client.swing.table.functional.IFunctionGroup;

public class FunctionColumnValueRetriever<V, F extends IFunction<IAdaptable, V>> extends AbstractColumnValueRetriever<V> {
    
    protected final Class<F> functionClass;
    private Class<V> functionValueType;
    
    public FunctionColumnValueRetriever(Class<F> functionClass, Class<V> functionValueType) {
        this.functionClass = functionClass;
        this.functionValueType = functionValueType;
    }
    
    @Override
    public Class<V> getValueType() {
        return functionValueType;
    }

    @Override
    public V getValue(IAdaptable rowObj) {
        F function = getRequiredFunction(functionClass);
        V value = function.evaluate(rowObj);
        if (functionValueType == null && value != null) {
            // Lazily initialize the functionValueType by the value retrieved from the function
            @SuppressWarnings("unchecked")
            Class<V> castClass = (Class<V>)value.getClass();
            functionValueType = castClass;
        }
        return value;
    }

    @Override
    public void getRequiredFunctions(IFunctionGroup<IAdaptable> functionGroup) {
        super.getRequiredFunctions(functionGroup);
        functionGroup.add(functionClass);
    }
}