/**
* Copyright (C) cedarsoft GmbH.
*
* Licensed under the GNU General Public License version 3 (the "License")
* with Classpath Exception; you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.cedarsoft.org/gpl3ce
* (GPL 3 with Classpath Exception)
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 3 only, as
* published by the Free Software Foundation. cedarsoft GmbH designates this
* particular file as subject to the "Classpath" exception as provided
* by cedarsoft GmbH in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 3 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 3 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact cedarsoft GmbH, 72810 Gomaringen, Germany,
* or visit www.cedarsoft.com if you need additional information or
* have any questions.
*/
package com.cedarsoft.test.io2;
import com.cedarsoft.UnsupportedVersionException;
import com.cedarsoft.Version;
import com.cedarsoft.VersionRange;
import com.cedarsoft.serialization.stax.AbstractStaxSerializer;
import com.cedarsoft.test.Money;
import javax.annotation.Nonnull;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.XMLStreamWriter;
import java.io.IOException;
/**
* This is an extended version of money serializer.
* <p/>
* It represents the next step of the evolution of MoneySerializer.
* This is an example for a refactoring that might happen, after the serializer has been
* released (and shipped to thousands of customers creating millions of files).
* <p/>
* Therefore this serializer is able to still read the old format.
* Writing is only supported for the latest file.
*/
public class MoneySerializer extends AbstractStaxSerializer<Money> {
public MoneySerializer() {
//This serializer supports an old version, too
super( "money", "http://thecompany.com/test/money", new VersionRange( new Version( 1, 0, 0 ), new Version( 1, 0, 1 ) ) );
}
@Override
public void serialize( @Nonnull XMLStreamWriter serializeTo, @Nonnull Money object, Version formatVersion ) throws IOException, XMLStreamException {
assert isVersionWritable( formatVersion );
serializeTo.writeAttribute( "cents", String.valueOf( object.getCents() ) );
//We use an attribute - just because it is possible...
}
@Override
public Money deserialize( XMLStreamReader deserializeFrom, Version formatVersion ) throws IOException, XMLStreamException {
assert isVersionReadable( formatVersion );
//This serializer supports reading of an old format. Therefore we have to switch based on the format version.
//This might be solved using the strategy pattern. But in most of the cases the format changes only in small portions.
//So it seems easier to add just one if/else.
//If a serializer evolves further a switch to the strategy pattern might be done. A simple map holding the strategies should do it.
//The common case - current version
if ( formatVersion.equals( new Version( 1, 0, 1 ) ) ) {
int cents = Integer.parseInt( deserializeFrom.getAttributeValue( null, "cents" ) );
//We have to close the tag! Every stax based serializer has to close its tag
//getText does this automatically for us. But when only using attributes, we have to close it manually.
closeTag( deserializeFrom );
return new Money( cents );
//The old format that does not use an attribute but text instead
} else if ( formatVersion.equals( new Version( 1, 0, 0 ) ) ) {
int cents = Integer.parseInt( getText( deserializeFrom ) );
//We don't have to close the tag. The getText method does that for us
return new Money( cents );
//Whoo - something went terribly wrong
} else {
throw new UnsupportedVersionException( formatVersion, getFormatVersionRange() );
}
}
}