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

import java.util.HashMap;
import java.util.Map;

/**
 * Default presenter implementation that simply returns the value passed to it.
 *
 * @param <V> the type of the value to present, which matches the value returned
 */
public class DefaultColumnValuePresenter<V> extends AbstractColumnValuePresenter<V, V> {
    
    /**
     * Cache of DefaultColumnValuePresenter instances, one per presentation type
     */
    private static final Map<Class<?>, DefaultColumnValuePresenter<?>> INSTANCE_CACHE = new HashMap<Class<?>, DefaultColumnValuePresenter<?>>();
    
    /**
     * Factory method to retrieve DefaultColumnValuePresenter instances
     * @param <V> the value type to present
     * @param presentationType the presentation value type
     * @return the presenter instance
     */
    public static <V> DefaultColumnValuePresenter<V> of(Class<V> presentationType) {
        if (presentationType == null) throw new IllegalArgumentException("presentationType"); //$NON-NLS-1$
        
        @SuppressWarnings("unchecked")
        DefaultColumnValuePresenter<V> instance = (DefaultColumnValuePresenter<V>)INSTANCE_CACHE.get(presentationType);
        if (instance == null) {
            instance = new DefaultColumnValuePresenter<V>(presentationType);
            INSTANCE_CACHE.put(presentationType, instance);
        }
        return instance;
    }
    
    /**
     * Factory method to retrieve DefaultColumnValuePresenter for unknown Object type
     * @return the presenter instance
     */
    public static DefaultColumnValuePresenter<Object> ofObjectType() {
        @SuppressWarnings("unchecked")
        DefaultColumnValuePresenter<Object> instance = (DefaultColumnValuePresenter<Object>)INSTANCE_CACHE.get(Object.class);
        if (instance == null) {
            instance = new DefaultColumnValuePresenter<Object>(Object.class);
            INSTANCE_CACHE.put(Object.class, instance);
        }
        return instance;
    }

    // Private constructor
    private DefaultColumnValuePresenter(Class<V> presentationType) {
        super(presentationType);
    }

    @Override
    public V getPresentation(V value, String identifier) {
        return value;
    }
}