001    /*
002     * Copyright (C) 2012 eXo Platform SAS.
003     *
004     * This is free software; you can redistribute it and/or modify it
005     * under the terms of the GNU Lesser General Public License as
006     * published by the Free Software Foundation; either version 2.1 of
007     * the License, or (at your option) any later version.
008     *
009     * This software is distributed in the hope that it will be useful,
010     * but WITHOUT ANY WARRANTY; without even the implied warranty of
011     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012     * Lesser General Public License for more details.
013     *
014     * You should have received a copy of the GNU Lesser General Public
015     * License along with this software; if not, write to the Free
016     * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
017     * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
018     */
019    package org.crsh.cli.impl.lang;
020    
021    /**
022     * @author Julien Viet
023     */
024    public interface Instance<T> {
025    
026      /**
027       * Resolve the specified contextual type to an instance or return null if no object able
028       * to satisfy the class type was resolved.
029       *
030       * @param type the type to resolve
031       * @param <T> the generic type parameter
032       * @return the resolved instance
033       */
034      <T> T resolve(Class<T> type);
035    
036      /**
037       * Return the instance, the same instance should be returned, however it can lazily be created.
038       *
039       * @return the instance
040       * @throws Exception any exception preventing to obtain the instance
041       */
042      T get() throws Exception;
043    
044    }