defaultconvertermanager.java

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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.dwrp;

import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

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.NamedConverter;
import org.directwebremoting.extend.OutboundContext;
import org.directwebremoting.extend.OutboundVariable;
import org.directwebremoting.extend.TypeHintContext;
import org.directwebremoting.util.LocalUtil;
import org.directwebremoting.util.Logger;
import org.directwebremoting.util.Messages;

/**
 * A class to manage the converter types and the instansiated class name matches.
 * @author Joe Walker [joe at getahead dot ltd dot uk]
 */
public class DefaultConverterManager implements ConverterManager
{
    /* (non-Javadoc)
     * @see org.directwebremoting.ConverterManager#addConverterType(java.lang.String, java.lang.String)
     */
    public void addConverterType(String id, String className)
    {
        if (!LocalUtil.isJavaIdentifier(id))
        {
            log.error("Illegal identifier: '" + id + "'");
            return;
        }

        Class clazz = LocalUtil.classForName(id, className, Converter.class);
        if (clazz != null)
        {
            log.debug("- adding converter type: " + id + " = " + clazz.getName());
            converterTypes.put(id, clazz);
        }
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.ConverterManager#addConverter(java.lang.String, java.lang.String, java.util.Map)
     */
    public void addConverter(String match, String type, Map params) throws IllegalArgumentException, InstantiationException, IllegalAccessException
    {
        Class clazz = (Class) converterTypes.get(type);
        if (clazz == null)
        {
            log.info("Probably not an issue: " + match + " is not available so the " + type + " converter will not load. This is only an problem if you wanted to use it.");
            return;
        }

        Converter converter = (Converter) clazz.newInstance();
        converter.setConverterManager(this);

        LocalUtil.setParams(converter, params, ignore);

        // add the converter for the specified match
        addConverter(match, converter);
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.ConverterManager#addConverter(java.lang.String, org.directwebremoting.Converter)
     */
    public void addConverter(String match, Converter converter) throws IllegalArgumentException
    {
        // Check that we don't have this one already
        Converter other = (Converter) converters.get(match);
        if (other != null)
        {
            log.warn("Clash of converters for " + match + ". Using " + converter.getClass().getName() + " in place of " + other.getClass().getName());
        }

        log.debug("- adding converter: " + LocalUtil.getShortClassName(converter.getClass()) + " for " + match);
        converters.put(match, converter);
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.ConverterManager#getConverterMatchStrings()
     */
    public Collection getConverterMatchStrings()
    {
        return Collections.unmodifiableSet(converters.keySet());
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.ConverterManager#getConverterByMatchString(java.lang.String)
     */
    public Converter getConverterByMatchString(String match)
    {
        return (Converter) converters.get(match);
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.ConverterManager#isConvertable(java.lang.Class)
     */
    public boolean isConvertable(Class paramType)
    {
        return getConverter(paramType) != null;
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.ConverterManager#convertInbound(java.lang.Class, org.directwebremoting.InboundVariable, org.directwebremoting.InboundContext, org.directwebremoting.TypeHintContext)
     */
    public Object convertInbound(Class paramType, InboundVariable iv, InboundContext inctx, TypeHintContext incc) throws MarshallException
    {
        Object converted = inctx.getConverted(iv, paramType);
        if (converted == null)
        {
            // Was the inbound variable marshalled as an Object in the client
            // (could mean that this is an instance of one of our generated
            // JavaScript classes)
            Converter converter = getNamedConverter(paramType, iv.getType());

            // Fall back to the standard way of locating a converter if we
            // didn't find anything above
            if (converter == null)
            {
                converter = getConverter(paramType);
            }

            if (converter == null)
            {
                throw new MarshallException(paramType, Messages.getString("DefaultConverterManager.MissingConverter", paramType));
            }

            // We only think about doing a null conversion ourselves once we are
            // sure that there is a converter available. This prevents hackers
            // from passing null to things they are not allowed to convert
            if (iv.isNull())
            {
                return null;
            }

            inctx.pushContext(incc);
            converted = converter.convertInbound(paramType, iv, inctx);
            inctx.popContext();
        }

        return converted;
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.ConverterManager#convertOutbound(java.lang.Object, org.directwebremoting.OutboundContext)
     */
    public OutboundVariable convertOutbound(Object object, OutboundContext outctx) throws MarshallException
    {
        if (object == null)
        {
            return new SimpleOutboundVariable("null", outctx, true);
        }

        // Check to see if we have done this one already
        OutboundVariable ov = outctx.get(object);
        if (ov != null)
        {
            // So the object as been converted already, we just need to refer to it.
            return ov.getReferenceVariable();
        }

        // So we will have to do the conversion
        Converter converter = getConverter(object);
        if (converter == null)
        {
            log.error(Messages.getString("DefaultConverterManager.MissingConverter", object.getClass().getName()));
            return new SimpleOutboundVariable("null", outctx, true);
        }

        return converter.convertOutbound(object, outctx);
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.ConverterManager#setExtraTypeInfo(org.directwebremoting.TypeHintContext, java.lang.Class)
     */
    public void setExtraTypeInfo(TypeHintContext thc, Class type)
    {
        extraTypeInfoMap.put(thc, type);
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.ConverterManager#getExtraTypeInfo(org.directwebremoting.TypeHintContext)
     */
    public Class getExtraTypeInfo(TypeHintContext thc)
    {
        Class type = (Class) extraTypeInfoMap.get(thc);
        return type;
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.ConverterManager#setConverters(java.util.Map)
     */
    public void setConverters(Map converters)
    {
        this.converters = converters;
    }

    /**
     * Like <code>getConverter(object.getClass());</code> except that since the
     * object can be null we check for that fist and then do a lookup against
     * the <code>Void.TYPE</code> converter
     * @param object The object to find a converter for