package com.sun.persistence.tools.apt;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import java.io.*;

/**
 * This class reads/writes Persistence XML deployment descriptor and builds a
 * descriptor object graph.
 *
 * @author Sanjeeb Sahoo
 * @version 1.0
 */
public class XMLReaderWriter {

    public PersistenceDescriptor read(InputStream is) throws IOException {
        try {
            JAXBContext jc = JAXBContext.newInstance(
                    PersistenceDescriptor.class.getPackage().getName(),
                    getClass().getClassLoader());
            Unmarshaller unmarshaller = jc.createUnmarshaller();
            return (PersistenceDescriptor) unmarshaller.unmarshal(is);
        } catch (JAXBException je) {
            je.printStackTrace();
            IOException ioe = new IOException();
            ioe.initCause(je);
            throw ioe;
        }
    }

    public void write(PersistenceDescriptor persistenceJar, OutputStream os)
            throws IOException {
        try {
            getMarshaller(persistenceJar.getClass()).marshal(persistenceJar,
                    os);
        } catch (JAXBException je) {
            je.printStackTrace();
            IOException ioe = new IOException();
            ioe.initCause(je);
            throw ioe;
        }
    }

    public void write(PersistenceDescriptor persistenceJar, Writer writer)
            throws IOException {
        try {
            getMarshaller(persistenceJar.getClass()).marshal(persistenceJar,
                    writer);
        } catch (JAXBException je) {
            je.printStackTrace();
            IOException ioe = new IOException();
            ioe.initCause(je);
            throw ioe;
        }
    }

    private Marshaller getMarshaller(Class<?> clazz) throws JAXBException {
        JAXBContext jc = JAXBContext.newInstance(clazz.getPackage().getName(),
                getClass().getClassLoader());
        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT,
                Boolean.TRUE);
        return marshaller;
    }

    public static void main(String... args) throws IOException {
        PersistenceDescriptor dd =
                new XMLReaderWriter().read(
                        new FileInputStream(new File(args[0])));
        new XMLReaderWriter().write(dd, System.out);
    }
}