com.cloudera.nav.sdk.client.writer.JsonMetadataWriter.java Source code

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Here is the source code for com.cloudera.nav.sdk.client.writer.JsonMetadataWriter.java

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/*
 * Copyright (c) 2015 Cloudera, Inc.
 *
 * Licensed 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 com.cloudera.nav.sdk.client.writer;

import com.cloudera.nav.sdk.client.ClientConfig;
import com.cloudera.nav.sdk.client.writer.serde.EntitySerializer;
import com.cloudera.nav.sdk.client.writer.serde.EntityV9Serializer;
import com.cloudera.nav.sdk.client.writer.serde.RelationSerializer;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.datatype.joda.JodaModule;
import com.google.common.base.Throwables;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;

import org.apache.commons.httpclient.HttpStatus;

/**
 * Write metadata in JSON format
 */
public class JsonMetadataWriter extends MetadataWriter {

    private final HttpURLConnection conn;
    private final ObjectMapper mapper;
    private ResultSet lastResult;

    public JsonMetadataWriter(ClientConfig config, OutputStream stream, HttpURLConnection conn) {
        super(config, stream);
        this.conn = conn;
        this.mapper = newMapper();
    }

    @Override
    protected void persistMetadataValues(MClassWrapper mclassWrapper) {
        try {
            mapper.writeValue(stream, mclassWrapper);
        } catch (IOException e) {
            Throwables.propagate(e);
        }
    }

    private ObjectMapper newMapper() {
        ObjectMapper mapper = new ObjectMapper();
        SimpleModule module = new SimpleModule("MetadataSerializer");
        if (config.getApiVersion() < 9) {
            module.addSerializer(new EntitySerializer(registry));
        } else {
            module.addSerializer(new EntityV9Serializer(registry));
        }
        module.addSerializer(new RelationSerializer(registry));
        mapper.registerModule(module);
        mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
        mapper.configure(DeserializationFeature.WRAP_EXCEPTIONS, false);
        mapper.registerModule(new JodaModule());
        return mapper;
    }

    @Override
    public void flush() {
        super.flush();
        try {
            // request is not sent until response code is requested
            if (conn.getResponseCode() >= HttpStatus.SC_BAD_REQUEST) {

                // display error message
                BufferedReader br = new BufferedReader(new InputStreamReader((conn.getErrorStream())));
                StringBuilder sb = new StringBuilder();
                String responseBody;
                while ((responseBody = br.readLine()) != null) {
                    sb.append(responseBody);
                }
                responseBody = sb.toString();

                throw new RuntimeException(String.format("Error writing metadata (code %s): %s %s",
                        conn.getResponseCode(), conn.getResponseMessage(), responseBody));
            }
            lastResult = mapper.readValue(conn.getInputStream(), ResultSet.class);
        } catch (IOException e) {
            Throwables.propagate(e);
        }
    }

    @Override
    public ResultSet getLastResultSet() {
        return lastResult;
    }
}