org.marid.runtime.model.Entity Maven / Gradle / Ivy

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package org.marid.runtime.model;

import org.w3c.dom.Element;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.io.StringReader;
import java.io.StringWriter;

public interface Entity extends Externalizable {

  @Override
  int hashCode();

  @Override
  boolean equals(Object obj);

  @Override
  String toString();

  ModelObjectFactory modelObjectFactory();

  String tag();

  void writeTo(Element element);

  void readFrom(Element element);

  @Override
  default void writeExternal(ObjectOutput out) throws IOException {
    try {
      final var document = DocumentBuilderFactory.newDefaultInstance().newDocumentBuilder().newDocument();
      final var element = document.createElement(tag());
      document.appendChild(element);
      writeTo(element);
      final var transformerFactory = TransformerFactory.newDefaultInstance();
      final var transformer = transformerFactory.newTransformer();
      final var stringWriter = new StringWriter();
      transformer.transform(new DOMSource(document), new StreamResult(stringWriter));
      out.writeUTF(stringWriter.toString());
    } catch (ParserConfigurationException | TransformerException e) {
      throw new IOException(e);
    }
  }

  @Override
  default void readExternal(ObjectInput in) throws IOException {
    try {
      final var documentBuilder = DocumentBuilderFactory.newDefaultInstance().newDocumentBuilder();
      final var document = documentBuilder.parse(new InputSource(new StringReader(in.readUTF())));
      final var element = document.getDocumentElement();
      if (!element.getTagName().equals(tag())) {
        throw new IllegalArgumentException("Tag mismatch: " + element.getTagName() + " != " + tag());
      }
      readFrom(element);
    } catch (ParserConfigurationException | SAXException e) {
      throw new IOException(e);
    }
  }
}