org.eclipse.scout.rt.jackson/src/main/java/org/eclipse/scout/rt/jackson/dataobject/DoDateDeserializer.java

/*
 * Copyright (c) 2010-2018 BSI Business Systems Integration AG.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     BSI Business Systems Integration AG - initial API and implementation
 */
package org.eclipse.scout.rt.jackson.dataobject;

import java.io.IOException;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

import org.eclipse.scout.rt.dataobject.IDoEntity;
import org.eclipse.scout.rt.dataobject.ValueFormat;
import org.eclipse.scout.rt.platform.util.LazyValue;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.deser.std.DateDeserializers.DateDeserializer;

/**
 * Custom {@link DateDeserializer} handling date values within {@link IDoEntity} which are annotated with custom
 * {@link ValueFormat} format.
 */
public class DoDateDeserializer extends DateDeserializer {
  private static final long serialVersionUID = 1L;

  protected final LazyValue<DoDateSerializationHelper> m_helper = new LazyValue<>(DoDateSerializationHelper.class);

  public DoDateDeserializer() {
  }

  public DoDateDeserializer(DateDeserializer base, DateFormat df, String formatString) {
    super(base, df, formatString);
  }

  @Override
  protected Date _parseDate(JsonParser p, DeserializationContext ctxt) throws IOException {
    SimpleDateFormat formatter = m_helper.get().findFormatter(p.getParsingContext());
    if (formatter != null) {
      // TODO bsh, pbz: Set the time zone of the formatter to the time zone of Jackson here
      // This would allow setting a custom time zone on the ObjectMapper. However, we should also set the default time zone
      // in Jackson to the default time zone of the system, otherwise the current behavior will be changed and the
      // serialized date strings change. Jackson uses UTC by default (https://github.com/fasterxml/jackson-databind/issues/915)
      // and it's not possible to change this. Therefore, every ObjectMapper instance which sets a custom date format
      // using om.setDateFormat(...), would also have to set om.setTimeZone(TimeZone.getDefault()). As this requires
      // adjustments to existing code, it should only be considered in a future major release.
      // Note: The same issue exist in DoDateSerializer.
      String str = p.getText().trim();
      try {
        return formatter.parse(str);
      }
      catch (ParseException e) {
        throw ctxt.weirdStringException(str, handledType(), "expected format [" + formatter.toPattern() + "]");
      }
    }
    return super._parseDate(p, ctxt);
  }

  @Override
  protected DateDeserializer withDateFormat(DateFormat df, String formatString) {
    return new DoDateDeserializer(this, df, formatString);
  }
}