Seasar2 を利用しなくても利用したい Seasar2 の ユーティリティ

総称型を取得するのに便利

1. GenericUtil
2. CollectionsUtil

example

package jp.mirageworld.dao;

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

import org.seasar.framework.util.tiger.GenericUtil;

@Stateless
@TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)
public class AbstractDao<E> {

    protected final Class<E> entityClass;

    @SuppressWarnings("unchecked")
    public AbstractDao() {
        Class<E> entityClass = null;
        Map<TypeVariable<?>, Type> map;
        map = GenericUtil.getTypeVariableMap(getClass());
        for (Class<?> c = getClass(); c != Object.class; c = c.getSuperclass()) {
            if (c.getSuperclass() == AbstractDao.class) {
                Type type = c.getGenericSuperclass();
                Type[] arrays = GenericUtil.getGenericParameters(type);
                entityClass = (Class<E>) GenericUtil.getActualClass(arrays[0], map);
                break;
            }
        }
        this.entityClass = entityClass;
    }
}