gateway-shell/src/main/java/org/apache/knox/gateway/shell/table/KnoxShellTableJSONSerializer.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.knox.gateway.shell.table;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Locale;

import org.apache.knox.gateway.util.JsonUtils;

import com.fasterxml.jackson.databind.ser.impl.SimpleBeanPropertyFilter;
import com.fasterxml.jackson.databind.ser.impl.SimpleFilterProvider;

/**
 * Utility class that helps serializing a {@link KnoxShellTable} in JSON format. The
 * reasons this class exists are:
 * <ol>
 * <li>to define the @DateFormat we use when serializing/deserializing a @Date
 * Object</li>
 * <li>conditionally exclude certain fields from the serialized JSON
 * representation</li>
 */
class KnoxShellTableJSONSerializer {

   static final DateFormat JSON_DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ", Locale.getDefault());

  /**
   * Serializes the given {@link KnoxShellTable}
   *
   * @param table
   *          the table to be serialized
   * @param data
   *          if this is <code>true</code> the underlying JSON serializer will
   *          output the table's content; otherwise the table's
   *          <code>callHistory</code> will be serilized
   * @return the serialized table in JSON format
   */
  static String serializeKnoxShellTable(KnoxShellTable table, boolean data) {
    SimpleFilterProvider filterProvider = new SimpleFilterProvider();
    if (data) {
      filterProvider.addFilter("knoxShellTableFilter", SimpleBeanPropertyFilter.filterOutAllExcept("headers", "rows", "title", "id"));
    } else {
      filterProvider.addFilter("knoxShellTableFilter", SimpleBeanPropertyFilter.filterOutAllExcept("callHistoryList"));
    }
    return JsonUtils.renderAsJsonString(table, filterProvider, JSON_DATE_FORMAT);
  }

}