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 java.lang.reflect.InvocationTargetException;

import org.apache.velocity.app.event.EventHandlerUtil;
import org.apache.velocity.context.InternalContextAdapter;
import org.apache.velocity.exception.MethodInvocationException;
import org.apache.velocity.exception.TemplateInitException;
import org.apache.velocity.exception.VelocityException;
import org.apache.velocity.runtime.RuntimeConstants;
import org.apache.velocity.runtime.parser.Parser;
import org.apache.velocity.util.introspection.Info;
import org.apache.velocity.util.introspection.IntrospectionCacheData;
import org.apache.velocity.util.introspection.VelPropertyGet;

/**
 *  ASTIdentifier.java
 *
 *  Method support for identifiers :  $foo
 *
 *  mainly used by ASTRefrence
 *
 *  Introspection is now moved to 'just in time' or at render / execution
 *  time. There are many reasons why this has to be done, but the
 *  primary two are   thread safety, to remove any context-derived
 *  information from class member  variables.
 *
 * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
 * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
 * @version $Id: ASTIdentifier.java 732250 2009-01-07 07:37:10Z byron $
 */
public class ASTIdentifier extends SimpleNode
{
    private String identifier = "";

    /**
     *  This is really immutable after the init, so keep one for this node
     */
    protected Info uberInfo;
    
    /**
     * Indicates if we are running in strict reference mode.
     */
    protected boolean strictRef = false;

    /**
     * @param id
     */
    public ASTIdentifier(int id)
    {
        super(id);
    }

    /**
     * @param p
     * @param id
     */
    public ASTIdentifier(Parser p, int id)
    {
        super(p, id);
    }


    /**
     * @see org.apache.velocity.runtime.parser.node.SimpleNode#jjtAccept(org.apache.velocity.runtime.parser.node.ParserVisitor, java.lang.Object)
     */
    public Object jjtAccept(ParserVisitor visitor, Object data)
    {
        return visitor.visit(this, data);
    }

    /**
     *  simple init - don't do anything that is context specific.
     *  just get what we need from the AST, which is static.
     * @param context
     * @param data
     * @return The data object.
     * @throws TemplateInitException
     */
    public  Object init(InternalContextAdapter context, Object data)
        throws TemplateInitException
    {
        super.init(context, data);

        identifier = getFirstToken().image.intern();

        uberInfo = new Info(getTemplateName(), getLine(), getColumn());

        strictRef = rsvc.getBoolean(RuntimeConstants.RUNTIME_REFERENCES_STRICT, false);
        
        return data;
    }

    /**
     * @see org.apache.velocity.runtime.parser.node.SimpleNode#execute(java.lang.Object, org.apache.velocity.context.InternalContextAdapter)
     */
    public Object execute(Object o, InternalContextAdapter context)
        throws MethodInvocationException
    {

        VelPropertyGet vg = null;

        try
        {
            /*
             *  first, see if we have this information cached.
             */

            IntrospectionCacheData icd = context.icacheGet(this);

            /*
             * if we have the cache data and the class of the object we are
             * invoked with is the same as that in the cache, then we must
             * be allright.  The last 'variable' is the method name, and
             * that is fixed in the template :)
             */

            if ( icd != null && (o != null) && (icd.contextData == o.getClass()) )
            {
                vg = (VelPropertyGet) icd.thingy;
            }
            else
            {
                /*
                 *  otherwise, do the introspection, and cache it.  Use the
                 *  uberspector
                 */

                vg = rsvc.getUberspect().getPropertyGet(o,identifier, uberInfo);

                if (vg != null && vg.isCacheable() && (o != null))
                {
                    icd = new IntrospectionCacheData();
                    icd.contextData = o.getClass();
                    icd.thingy = vg;
                    context.icachePut(this,icd);
                }
            }
        }

        /**
         * pass through application level runtime exceptions
         */
        catch( RuntimeException e )
        {
            throw e;
        }
        catch(Exception e)
        {
            String msg = "ASTIdentifier.execute() : identifier = "+identifier;
            log.error(msg, e);
            throw new VelocityException(msg, e);
        }

        /*
         *  we have no getter... punt...
         */

        if (vg == null)
        {
            if (strictRef)
            {
                throw new MethodInvocationException("Object '" + o.getClass().getName() +              
                    "' does not contain property '" + identifier + "'", null, identifier,
                    uberInfo.getTemplateName(), uberInfo.getLine(), uberInfo.getColumn());
            }
            else
            {
                return null;
            }
        }

        /*
         *  now try and execute.  If we get a MIE, throw that
         *  as the app wants to get these.  If not, log and punt.
         */
        try
        {
            return vg.invoke(o);
        }
        catch(InvocationTargetException ite)
        {
            /*
             *  if we have an event cartridge, see if it wants to veto
             *  also, let non-Exception Throwables go...
             */

            Throwable t = ite.getTargetException();
            if (t instanceof Exception)
            {
                try
                {
                    return EventHandlerUtil.methodException(rsvc, context, o.getClass(), vg.getMethodName(),
                            (Exception) t);
                }

                /**
                 * If the event handler throws an exception, then wrap it
                 * in a MethodInvocationException.  Don't pass through RuntimeExceptions like other
                 * similar catchall code blocks.
                 */
                catch( Exception e )
                {
                    throw new MethodInvocationException(
                      "Invocation of method '" + vg.getMethodName() + "'"
                      + " in  " + o.getClass()
                      + " threw exception "
                      + ite.getTargetException().toString(),
                      ite.getTargetException(), vg.getMethodName(), getTemplateName(), this.getLine(), this.getColumn());
                }
            }
            else
            {
                /*
                 * no event cartridge to override. Just throw
                 */

                throw  new MethodInvocationException(
                "Invocation of method '" + vg.getMethodName() + "'"
                + " in  " + o.getClass()
                + " threw exception "
                + ite.getTargetException().toString(),
                ite.getTargetException(), vg.getMethodName(), getTemplateName(), this.getLine(), this.getColumn());


            }
        }
        catch(IllegalArgumentException iae)
        {
            return null;
        }
        /**
         * pass through application level runtime exceptions
         */
        catch( RuntimeException e )
        {
            throw e;
        }
        catch(Exception e)
        {
            String msg = "ASTIdentifier() : exception invoking method "
                        + "for identifier '" + identifier + "' in "
                        + o.getClass();
            log.error(msg, e);
            throw new VelocityException(msg, e);
        }
    }
}
