content: /*
   * 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.ambari.server.state.quicklinksprofile;
  
  import java.io.IOException;
  import java.net.URL;
  import java.util.ArrayList;
  import java.util.List;
  
  import com.fasterxml.jackson.annotation.JsonInclude;
  import com.fasterxml.jackson.core.JsonParseException;
  import com.fasterxml.jackson.core.JsonParser;
  import com.fasterxml.jackson.core.JsonProcessingException;
  import com.fasterxml.jackson.core.Version;
  import com.fasterxml.jackson.databind.DeserializationContext;
  import com.fasterxml.jackson.databind.ObjectMapper;
  import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
  import com.fasterxml.jackson.databind.module.SimpleModule;
  import com.fasterxml.jackson.databind.node.ObjectNode;
  import com.google.common.collect.ImmutableList;
  import com.google.common.io.Resources;
  
  /**
   * Loads and parses JSON quicklink profiles.
   */
  public class QuickLinksProfileParser {
    private final ObjectMapper mapper = new ObjectMapper();
  
    public QuickLinksProfileParser() {
      SimpleModule module =
          new SimpleModule("Quick Links Parser", new Version(1, 0, 0, null, null, null));
      module.addDeserializer(Filter.class, new QuickLinksFilterDeserializer());
      mapper.registerModule(module);
      mapper.setSerializationInclusion(JsonInclude.Include.NON_EMPTY);
    }
  
    public QuickLinksProfile parse(byte[] input) throws IOException {
      return mapper.readValue(input, QuickLinksProfile.class);
    }
  
    public QuickLinksProfile parse(URL url) throws IOException {
      return parse(Resources.toByteArray(url));
    }
  
    public String encode(QuickLinksProfile profile) throws IOException {
      return mapper.writeValueAsString(profile);
    }
  }
  
  /**
   * Custom deserializer is needed to handle filter polymorphism.
   */
  class QuickLinksFilterDeserializer extends StdDeserializer<Filter> {
    static final String PARSE_ERROR_MESSAGE_AMBIGUOUS_FILTER =
        "A filter is not allowed to declare both link_name and link_attribute at the same time.";
  
    static final String PARSE_ERROR_MESSAGE_INVALID_JSON_TAG =
        "Invalid attribute(s) in filter declaration: ";
  
    QuickLinksFilterDeserializer() {
      super(Filter.class);
    }
  
    /**
     * Filter polymorphism is handled here. If a filter object in the JSON document has:
     * <ul>
     *   <li>a {@code link_attribute} field, it will parsed as {@link LinkAttributeFilter}</li>
     *   <li>a {@code link_name} field, it will be parsed as {@link LinkNameFilter}</li>
     *   <li>both {@code link_attribute} and {@code link_name}, it will throw a {@link JsonParseException}</li>
     *   <li>neither of the above fields, it will be parsed as {@link AcceptAllFilter}</li>
     * </ul>
     *
     * @throws JsonParseException if ambiguous filter definitions are found, or any JSON syntax error.
     */
    @Override
    public Filter deserialize (JsonParser parser, DeserializationContext context) throws IOException, JsonProcessingException {
      ObjectMapper mapper = (ObjectMapper) parser.getCodec();
      ObjectNode root = mapper.readTree(parser);
      Class<? extends Filter> filterClass = null;
      List<String> invalidAttributes = new ArrayList<>();
      for (String fieldName: ImmutableList.copyOf(root.fieldNames())) {
        switch(fieldName) {
          case LinkAttributeFilter.LINK_ATTRIBUTE:
            if (null != filterClass) {
              throw new JsonParseException(parser, PARSE_ERROR_MESSAGE_AMBIGUOUS_FILTER, parser.getCurrentLocation());
            }
            filterClass = LinkAttributeFilter.class;
            break;
          case LinkNameFilter.LINK_NAME:
          case LinkNameFilter.LINK_URL:
            if (null != filterClass && !filterClass.equals(LinkNameFilter.class)) {
              throw new JsonParseException(parser, PARSE_ERROR_MESSAGE_AMBIGUOUS_FILTER, parser.getCurrentLocation());
            }
            filterClass = LinkNameFilter.class;
            break;
          case Filter.VISIBLE:
            // silently ignore here, will be parsed later in mapper.readValue
            break;
          default:
            invalidAttributes.add(fieldName);
        }
      }
      if (!invalidAttributes.isEmpty()) {
        throw new JsonParseException(parser, PARSE_ERROR_MESSAGE_INVALID_JSON_TAG + invalidAttributes,
            parser.getCurrentLocation());
      }
      if (null == filterClass) {
        filterClass = AcceptAllFilter.class;
      }
      return mapper.readValue(root.traverse(), filterClass);
    }
  }