SimpleJsonFileStorageImpl.java

package fxutil.doc;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Collection;
import java.util.Collections;

public abstract class SimpleJsonFileStorageImpl<T> extends AbstractDocumentStorageImpl<T, File>
implements IDocumentStorage<File> {

  private T document;

  private final ObjectMapper objectMapper;

  private final Class<T> documentClass;

  public SimpleJsonFileStorageImpl(final Class<T> documentClass) {
    this.documentClass = documentClass;
    final SimpleModule module = new SimpleModule();
    configureJacksonModule(module);
    objectMapper = new ObjectMapper();
    objectMapper.registerModule(module);
  }

  protected abstract void configureJacksonModule(final SimpleModule module);

  @Override
  public T loadDocument(final InputStream inputStream) throws Exception {
    return objectMapper.readValue(inputStream, documentClass);
  }

  @Override
  public void saveDocument(final T document, final File documentLocation) throws Exception {
    try (OutputStream outputStream = new FileOutputStream(documentLocation, false)) {
      objectMapper.writeValue(outputStream, document);
    }
  }

  @Override
  public Collection<IDocumentImporter> getDocumentImporters() {
    return Collections.emptyList();
  }

  @Override
  public T getDocument() {
    return document;
  }

  @Override
  public void setDocument(final T document) {
    final T oldDocument = this.document;
    this.document = document;
    fireDocumentChanged(oldDocument);
  }

  @Override
  protected T createDocument() {
    try {
      return documentClass.getDeclaredConstructor().newInstance();
    } catch (final Exception e) {
      throw new RuntimeException("Exception when instantiating " + documentClass, e);
    }
  }
}