com.concentricsky.android.khanacademy.data.remote.VideoDeserializerModule.java Source code

Introduction

Here is the source code for com.concentricsky.android.khanacademy.data.remote.VideoDeserializerModule.java

Source

/*
Viewer for Khan Academy
Copyright (C) 2012 Concentric Sky, Inc.
    
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
    
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
    
You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.concentricsky.android.khanacademy.data.remote;

import java.io.IOException;
import java.util.Iterator;

import com.concentricsky.android.khanacademy.data.db.Video;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.TreeNode;
import com.fasterxml.jackson.core.Version;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.deser.std.StdScalarDeserializer;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.databind.node.ObjectNode;

public class VideoDeserializerModule extends SimpleModule {
    private static final long serialVersionUID = 1990628478880621620L;

    private ObjectMapper defaultMapper;

    public VideoDeserializerModule() {
        super("VideoDeserializerModule", new Version(1, 0, 0, null, "com.concentricsky.android", "khanacademy"));
        this.addDeserializer(Video.class, new VideoDeserializer());
        defaultMapper = new ObjectMapper();
    }

    public final class VideoDeserializer extends StdScalarDeserializer<Video> {
        private static final long serialVersionUID = 7599380630777421226L;

        public VideoDeserializer() {
            super(Video.class);
        }

        @Override
        public Video deserialize(JsonParser jp, DeserializationContext ctxt)
                throws IOException, JsonProcessingException {

            // First, do the default deserialization.
            TreeNode tree = defaultMapper.readTree(jp);
            Video video = defaultMapper.treeToValue(tree, Video.class);

            // Then, in case this video came from the child list of a Topic's detail record, copy the 'id' onto 'readable_id'.
            try {
                // ClassCastException if this is really a NullNode.
                // That should never happen. I think it was just happening because I was accidentally trying to consume the video twice.
                ObjectNode root = (ObjectNode) tree;
                Iterator<String> keys = root.fieldNames();

                while (keys.hasNext()) {
                    String key = keys.next();
                    if ("id".equals(key)) {
                        JsonNode value = root.get(key);
                        if (value.isTextual()) {
                            video.setReadable_id(value.asText());
                        }
                    }
                }
            } catch (ClassCastException e) {
                e.printStackTrace();
                // fall through and return video unchanged.
            }

            return video;
        }

    }

}