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.lang.groovy.closure;
020    
021    import groovy.lang.Closure;
022    import org.crsh.command.CommandContext;
023    import org.crsh.command.CommandInvoker;
024    
025    import java.io.IOException;
026    
027    /** @author Julien Viet */
028    public class ClosureInvoker extends CommandInvoker<Object, Object> {
029    
030      /** . */
031      private final Closure closure;
032    
033      /** . */
034      private final Class<?> type;
035    
036      /** . */
037      private CommandContext<? super Object> consumer;
038    
039      public ClosureInvoker(Closure closure) {
040    
041        // Resolve the closure consumed type
042        final Class<?> type;
043        Class[] parameterTypes = closure.getParameterTypes();
044        if (parameterTypes != null && parameterTypes.length > 0) {
045          type = parameterTypes[0];
046        } else {
047          type = Object.class;
048        }
049    
050        //
051        this.type = type;
052        this.closure = closure;
053      }
054    
055      public Class<Object> getProducedType() {
056        return Object.class;
057      }
058      public Class<Object> getConsumedType() {
059        return Object.class;
060      }
061      public void provide(Object element) throws IOException {
062        if (type.isInstance(element)) {
063          Object ret = closure.call(element);
064          if (ret != null) {
065            consumer.provide(ret);
066          }
067        }
068      }
069    
070      public void open(CommandContext<? super Object> consumer) {
071        this.consumer = consumer;
072        ClosureDelegate delegate = new ClosureDelegate(consumer, closure.getOwner());
073        closure.setResolveStrategy(Closure.DELEGATE_FIRST);
074        closure.setDelegate(delegate);
075      }
076    
077      public void flush() throws IOException {
078        consumer.flush();
079      }
080    
081      public void close() {
082        consumer = null;
083      }
084    }