com.googlecode.objectify.util.GenericUtils Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of objectify Show documentation

The simplest convenient interface to the Google App Engine datastore

There is a newer version: 6.1.2

package com.googlecode.objectify.util;

import com.googlecode.objectify.repackaged.gentyref.GenericTypeReflector;

import java.lang.reflect.Type;
import java.util.Collection;
import java.util.Map;

/**
 */
public class GenericUtils
{
	private GenericUtils() {
	}

	/**
	 * Get the component type of a Collection.
	 */
	public static Type getCollectionComponentType(Type collectionType) {
		Type componentType = GenericTypeReflector.getTypeParameter(collectionType, Collection.class.getTypeParameters()[0]);
		if (componentType == null)	// if it was a raw type, just assume Object
			return Object.class;
		else
			return componentType;
	}

	/**
	 * Get the key type of a Map.
	 */
	public static Type getMapKeyType(Type mapType) {
		Type componentType = GenericTypeReflector.getTypeParameter(mapType, Map.class.getTypeParameters()[0]);
		if (componentType == null)	// if it was a raw type, just assume Object
			return Object.class;
		else
			return componentType;
	}

	/**
	 * Get the value type of a Map.
	 */
	public static Type getMapValueType(Type mapType) {
		Type componentType = GenericTypeReflector.getTypeParameter(mapType, Map.class.getTypeParameters()[1]);
		if (componentType == null)	// if it was a raw type, just assume Object
			return Object.class;
		else
			return componentType;
	}
}