import org.codelibs.core.collection.CollectionsUtil;

/**
 * Utility class for handling generics in Java.
 *
 * @author koichik
 */
public abstract class GenericsUtil {

    /**
     * Do not instantiate.
     */
    protected GenericsUtil() {
    }

    /**
     * Returns <code>true</code> if the raw type of <code>type</code> can be assigned to <code>clazz</code>,
     * <code>false</code> otherwise.
     *

        assertThat(GenericsUtil.isTypeOf(t1, Set.class), is(true));
        assertThat(GenericsUtil.getElementTypeOfSet(t1), is(sameClass(String.class)));

        final Method m2 = SetType.class.getMethod("setOfClass");
        final Type t2 = m2.getGenericReturnType();
        assertThat(GenericsUtil.isTypeOf(t2, Set.class), is(true));

        assertArgumentNotNull("method", method);

        final Type[] parameterTypes = method.getGenericParameterTypes();
        return GenericsUtil.getRawClass(GenericsUtil.getElementTypeOfCollection(parameterTypes[position]));
    }

    /**
     * Returns the element type of the parameterized collection declared as the method's return type.
     *
     * @param method

     */
    public static Class<?> getElementTypeOfCollection(final Field field) {
        assertArgumentNotNull("field", field);

        final Type type = field.getGenericType();
        return GenericsUtil.getRawClass(GenericsUtil.getElementTypeOfCollection(type));
    }

    /**
     * Returns the key type of a parameterized map field.
     *
     * @param field a field of a parameterized map type (must not be {@literal null})

import static org.codelibs.core.collection.CollectionsUtil.newHashSet;
import static org.codelibs.core.lang.GenericsUtil.getActualClass;
import static org.codelibs.core.lang.GenericsUtil.getGenericParameters;
import static org.codelibs.core.lang.GenericsUtil.getTypeVariableMap;
import static org.codelibs.core.misc.AssertionUtil.assertArgumentArrayIndex;