velocity-engine-core/src/main/java/org/apache/velocity/runtime/parser/node/MapSetExecutor.java

package org.apache.velocity.runtime.parser.node;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import org.apache.velocity.exception.VelocityException;
import org.slf4j.Logger;

import java.util.Map;

/**
 * SetExecutor that is smart about Maps. If it detects one, it does not
 * use Reflection but a cast to access the setter.
 *
 * @author <a href="mailto:henning@apache.org">Henning P. Schmiedehausen</a>
 * @version $Id$
 * @since 1.5
 */
public class MapSetExecutor
        extends SetExecutor
{
    private final String property;

    public MapSetExecutor(final Logger log, final Class clazz, final String property)
    {
        this.log = log;
        this.property = property;
        discover(clazz);
    }

    protected void discover (final Class clazz)
    {
        Class [] interfaces = clazz.getInterfaces();
        for (Class anInterface : interfaces)
        {
            if (anInterface.equals(Map.class))
            {
                try
                {
                    if (property != null)
                    {
                        setMethod(Map.class.getMethod("put", Object.class, Object.class));
                    }
                }
                /**
                 * pass through application level runtime exceptions
                 */
                catch (RuntimeException e)
                {
                    throw e;
                }
                catch (Exception e)
                {
                    String msg = "Exception while looking for put('" + property + "') method";
                    log.error(msg, e);
                    throw new VelocityException(msg, e);
                }
                break;
            }
        }
    }

    public Object execute(final Object o, final Object arg)
    {
        return ((Map) o).put(property, arg);
    }
}