lightning-maven-plugin/src/main/java/org/apache/directmemory/lightning/maven/SourceMarshallerGenerator.java

/*
 * 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.
 */
package org.apache.directmemory.lightning.maven;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStreamWriter;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Properties;

import org.apache.directmemory.lightning.SerializationStrategy;
import org.apache.directmemory.lightning.logging.Logger;
import org.apache.directmemory.lightning.metadata.PropertyDescriptor;
import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.VelocityEngine;

public class SourceMarshallerGenerator
{

    private final VelocityEngine engine;

    private final Template marshallerTemplate;

    private final Charset charset;

    private final Logger logger;

    public SourceMarshallerGenerator( Charset charset, Logger logger )
        throws IOException
    {
        this.charset = charset;
        this.logger = logger;

        Properties properties = new Properties();
        InputStream stream = getClass().getClassLoader().getResourceAsStream( "velocity.properties" );
        properties.load( stream );
        engine = new VelocityEngine( properties );

        engine.init();
        marshallerTemplate = engine.getTemplate( "marshaller.vm", "UTF-8" );
    }

    public File generateMarshaller( Class<?> type, List<PropertyDescriptor> propertyDescriptors,
                                    SerializationStrategy serializationStrategy, File outputFolder )
        throws IOException
    {

        // Copy properties and sort them by name
        List<PropertyDescriptor> propertyDescriptorsCopy = new ArrayList<PropertyDescriptor>( propertyDescriptors );
        Collections.sort( propertyDescriptorsCopy );

        String packageName = type.getPackage() != null ? type.getPackage().getName() : "lightning";
        String className = type.getName().replace( packageName + ".", "" ) + "LightningGeneratedMarshaller";

        File packageFolder = new File( outputFolder, packageName.replace( ".", "/" ) );
        if ( !packageFolder.exists() )
        {
            packageFolder.mkdirs();
        }

        File outputFile = new File( packageFolder, className + ".java" );

        logger.info( "Generating source :" + outputFile.getAbsolutePath() );

        FileOutputStream stream = new FileOutputStream( outputFile );
        OutputStreamWriter writer = new OutputStreamWriter( stream, charset );

        VelocityContext context = new VelocityContext();

        context.put( "support", new Support() );
        context.put( "packageName", packageName );
        context.put( "className", className );
        context.put( "properties", propertyDescriptorsCopy );
        context.put( "strategy", serializationStrategy.name() );

        marshallerTemplate.merge( context, writer );

        writer.flush();
        writer.close();

        return outputFile;
    }

    public static class Support
    {

        public String toFinalFieldName( String prefix, PropertyDescriptor propertyDescriptor )
        {
            return new StringBuilder( prefix.toUpperCase() ).append( "_" ).append( propertyDescriptor.getPropertyName().toUpperCase() ).append( "_LIGHTNING" ).toString();
        }

        public String generateWriter( PropertyDescriptor propertyDescriptor, String instanceName )
        {
            StringBuilder sb =
                new StringBuilder( propertyDescriptor.getPropertyName() ).append( "PropertyAccessor.write" );
            Class<?> type = propertyDescriptor.getType();
            if ( type == boolean.class )
            {
                sb.append( "Boolean(" ).append( instanceName ).append( ", ((Boolean) " ).append( propertyDescriptor.getPropertyName() ).append( "Value" ).append( ").booleanValue())" );
            }
            else if ( type == byte.class )
            {
                sb.append( "Byte(" ).append( instanceName ).append( ", ((Byte) " ).append( propertyDescriptor.getPropertyName() ).append( "Value" ).append( ").byteValue())" );
            }
            else if ( type == char.class )
            {
                sb.append( "Char(" ).append( instanceName ).append( ", ((Character) " ).append( propertyDescriptor.getPropertyName() ).append( "Value" ).append( ").charValue())" );
            }
            else if ( type == short.class )
            {
                sb.append( "Short(" ).append( instanceName ).append( ", ((Short) " ).append( propertyDescriptor.getPropertyName() ).append( "Value" ).append( ").shortValue())" );
            }
            else if ( type == int.class )
            {
                sb.append( "Int(" ).append( instanceName ).append( ", ((Integer) " ).append( propertyDescriptor.getPropertyName() ).append( "Value" ).append( ").intValue())" );
            }
            else if ( type == long.class )
            {
                sb.append( "Long(" ).append( instanceName ).append( ", ((Long) " ).append( propertyDescriptor.getPropertyName() ).append( "Value" ).append( ").longValue())" );
            }
            else if ( type == float.class )
            {
                sb.append( "Float(" ).append( instanceName ).append( ", ((Float) " ).append( propertyDescriptor.getPropertyName() ).append( "Value" ).append( ").floatValue())" );
            }
            else if ( type == double.class )
            {
                sb.append( "Double(" ).append( instanceName ).append( ", ((Double) " ).append( propertyDescriptor.getPropertyName() ).append( "Value" ).append( ").doubleValue())" );
            }
            else
            {
                sb.append( "Object(" ).append( instanceName ).append( ", " ).append( propertyDescriptor.getPropertyName() ).append( "Value" ).append( ")" );
            }

            return sb.append( ";" ).toString();
        }

        public String generateReader( PropertyDescriptor propertyDescriptor )
        {
            StringBuilder sb = new StringBuilder();
            Class<?> type = propertyDescriptor.getType();
            if ( type == boolean.class )
            {
                sb.append( "Boolean.valueOf(" ).append( propertyDescriptor.getPropertyName() ).append( "PropertyAccessor" ).append( ".readBoolean(" );
            }
            else if ( type == byte.class )
            {
                sb.append( "Byte.valueOf(" ).append( propertyDescriptor.getPropertyName() ).append( "PropertyAccessor" ).append( ".readByte(" );
            }
            else if ( type == char.class )
            {
                sb.append( "Character.valueOf(" ).append( propertyDescriptor.getPropertyName() ).append( "PropertyAccessor" ).append( ".readChar(" );
            }
            else if ( type == short.class )
            {
                sb.append( "Short.valueOf(" ).append( propertyDescriptor.getPropertyName() ).append( "PropertyAccessor" ).append( ".readShort(" );
            }
            else if ( type == int.class )
            {
                sb.append( "Integer.valueOf(" ).append( propertyDescriptor.getPropertyName() ).append( "PropertyAccessor" ).append( ".readInt(" );
            }
            else if ( type == long.class )
            {
                sb.append( "Long.valueOf(" ).append( propertyDescriptor.getPropertyName() ).append( "PropertyAccessor" ).append( ".readLong(" );
            }
            else if ( type == float.class )
            {
                sb.append( "Float.valueOf(" ).append( propertyDescriptor.getPropertyName() ).append( "PropertyAccessor" ).append( ".readFloat(" );
            }
            else if ( type == double.class )
            {
                sb.append( "Double.valueOf(" ).append( propertyDescriptor.getPropertyName() ).append( "PropertyAccessor" ).append( ".readDouble(" );
            }
            else
            {
                sb.append( propertyDescriptor.getPropertyName() ).append( "PropertyAccessor" ).append( ".readObject(" );
            }

            sb.append( "value)" );

            if ( type.isPrimitive() )
            {
                sb.append( ")" );
            }

            return sb.toString();
        }
    }
}