org.directwebremoting.convert.MapConverter Maven / Gradle / Ivy

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DWR is easy Ajax for Java. It makes it simple to call Java code directly from Javascript. It gets rid of almost all the boiler plate code between the web browser and your Java code.
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/*
 * Copyright 2005 Joe Walker
 *
 * Licensed 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.
 */
package org.directwebremoting.convert;

import java.lang.reflect.Modifier;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.StringTokenizer;

import org.directwebremoting.dwrp.ParseUtil;
import org.directwebremoting.dwrp.ProtocolConstants;
import org.directwebremoting.dwrp.ObjectOutboundVariable;
import org.directwebremoting.extend.Converter;
import org.directwebremoting.extend.ConverterManager;
import org.directwebremoting.extend.InboundContext;
import org.directwebremoting.extend.InboundVariable;
import org.directwebremoting.extend.MarshallException;
import org.directwebremoting.extend.OutboundContext;
import org.directwebremoting.extend.OutboundVariable;
import org.directwebremoting.extend.TypeHintContext;
import org.directwebremoting.util.JavascriptUtil;
import org.directwebremoting.util.LocalUtil;
import org.directwebremoting.util.Logger;
import org.directwebremoting.util.Messages;

/**
 * An implementation of Converter for Maps.
 * @author Joe Walker [joe at eireneh dot com]
 * @version $Id: StringConverter.java,v 1.2 2004/11/04 15:54:07 joe_walker Exp $
 */
public class MapConverter implements Converter
{
    /* (non-Javadoc)
     * @see org.directwebremoting.Converter#setConverterManager(org.directwebremoting.ConverterManager)
     */
    public void setConverterManager(ConverterManager newConfig)
    {
        this.config = newConfig;
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.Converter#convertInbound(java.lang.Class, org.directwebremoting.InboundVariable, org.directwebremoting.InboundContext)
     */
    public Object convertInbound(Class paramType, InboundVariable iv, InboundContext inctx) throws MarshallException
    {
        String value = iv.getValue();

        // If the text is null then the whole bean is null
        if (value.trim().equals(ProtocolConstants.INBOUND_NULL))
        {
            return null;
        }

        if (!value.startsWith(ProtocolConstants.INBOUND_MAP_START))
        {
            throw new IllegalArgumentException(Messages.getString("MapConverter.FormatError", ProtocolConstants.INBOUND_MAP_START));
        }

        if (!value.endsWith(ProtocolConstants.INBOUND_MAP_END))
        {
            throw new IllegalArgumentException(Messages.getString("MapConverter.FormatError", ProtocolConstants.INBOUND_MAP_END));
        }

        value = value.substring(1, value.length() - 1);

        try
        {
            // Maybe we ought to check that the paramType isn't expecting a more
            // distinct type of Map and attempt to create that?
            Map map;

            // If paramType is concrete then just use whatever we've got.
            if (!paramType.isInterface() && !Modifier.isAbstract(paramType.getModifiers()))
            {
                // If there is a problem creating the type then we have no way
                // of completing this - they asked for a specific type and we
                // can't create that type. I don't know of a way of finding
                // subclasses that might be instaniable so we accept failure.
                map = (Map) paramType.newInstance();
            }
            else
            {
                map = new HashMap();
            }

            // Get the extra type info
            TypeHintContext thc = inctx.getCurrentTypeHintContext();

            TypeHintContext keyThc = thc.createChildContext(0);
            Class keyType = keyThc.getExtraTypeInfo();

            TypeHintContext valThc = thc.createChildContext(1);
            Class valType = valThc.getExtraTypeInfo();

            // We should put the new object into the working map in case it
            // is referenced later nested down in the conversion process.
            inctx.addConverted(iv, paramType, map);
            InboundContext incx = iv.getLookup();

            // Loop through the property declarations
            StringTokenizer st = new StringTokenizer(value, ",");
            int size = st.countTokens();
            for (int i = 0; i < size; i++)
            {
                String token = st.nextToken();
                if (token.trim().length() == 0)
                {
                    continue;
                }

                int colonpos = token.indexOf(ProtocolConstants.INBOUND_MAP_ENTRY);
                if (colonpos == -1)
                {
                    throw new MarshallException(paramType, Messages.getString("MapConverter.MissingSeparator", ProtocolConstants.INBOUND_MAP_ENTRY, token));
                }

                // Convert the value part of the token by splitting it into the
                // type and value (as passed in by Javascript)
                String valStr = token.substring(colonpos + 1).trim();
                String[] splitIv = ParseUtil.splitInbound(valStr);
                String splitIvValue = splitIv[LocalUtil.INBOUND_INDEX_VALUE];
                String splitIvType = splitIv[LocalUtil.INBOUND_INDEX_TYPE];
                InboundVariable valIv = new InboundVariable(incx, null, splitIvType, splitIvValue);
                Object val = config.convertInbound(valType, valIv, inctx, valThc);

                // Keys (unlike values) do not have type info passed with them
                // Could we have recurrsive key? - I don't think so because keys
                // must be strings in Javascript
                String keyStr = token.substring(0, colonpos).trim();
                //String[] keySplit = LocalUtil.splitInbound(keyStr);
                //InboundVariable keyIv = new InboundVariable(incx, splitIv[LocalUtil.INBOUND_INDEX_TYPE], splitIv[LocalUtil.INBOUND_INDEX_VALUE]);
                InboundVariable keyIv = new InboundVariable(incx, null, ProtocolConstants.TYPE_STRING, keyStr);
                Object key = config.convertInbound(keyType, keyIv, inctx, keyThc);

                map.put(key, val);
            }

            return map;
        }
        catch (MarshallException ex)
        {
            throw ex;
        }
        catch (Exception ex)
        {
            throw new MarshallException(paramType, ex);
        }
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.Converter#convertOutbound(java.lang.Object, org.directwebremoting.OutboundContext)
     */
    public OutboundVariable convertOutbound(Object data, OutboundContext outctx) throws MarshallException
    {
        // First we just collect our converted children
        Map ovs = (Map) LocalUtil.classNewInstance("OrderedConvertOutbound", "java.util.LinkedHashMap", Map.class);
        if (ovs == null)
        {
            ovs = new HashMap();
        }

        ObjectOutboundVariable ov = new ObjectOutboundVariable(outctx);
        outctx.put(data, ov);

        // Loop through the map outputting any init code and collecting
        // converted outbound variables into the ovs map
        Map map = (Map) data;
        for (Iterator it = map.entrySet().iterator(); it.hasNext();)
        {
            Map.Entry entry = (Map.Entry) it.next();
            Object key = entry.getKey();
            Object value = entry.getValue();

            // It would be nice to check for Enums here
            if (!(key instanceof String) && !sentNonStringWarning)
            {
                log.warn("--Javascript does not support non string keys. Converting '" + key.getClass().getName() + "' using toString()");
                sentNonStringWarning = true;
            }

            String outkey = JavascriptUtil.escapeJavaScript(key.toString());

            // OutboundVariable ovkey = config.convertOutbound(key, outctx);
            // buffer.append(ovkey.getInitCode());
            // outkey = ovkey.getAssignCode();

            OutboundVariable nested = config.convertOutbound(value, outctx);

            ovs.put(outkey, nested);
        }

        ov.init(ovs, null);

        return ov;
    }

    /**
     * We don't want to give the non-string warning too many times.
     */
    private static boolean sentNonStringWarning = false;

    /**
     * To forward marshalling requests
     */
    private ConverterManager config = null;

    /**
     * The log stream
     */
    private static final Logger log = Logger.getLogger(MapConverter.class);
}