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.apex.malhar.contrib.formatter;
  
  import java.io.IOException;
  import java.io.StringWriter;
  import java.util.List;
  
  import javax.validation.constraints.NotNull;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.supercsv.cellprocessor.FmtDate;
  import org.supercsv.cellprocessor.Optional;
  import org.supercsv.cellprocessor.ift.CellProcessor;
  import org.supercsv.exception.SuperCsvException;
  import org.supercsv.io.CsvBeanWriter;
  import org.supercsv.io.ICsvBeanWriter;
  import org.supercsv.prefs.CsvPreference;
  
  import org.apache.apex.malhar.contrib.parser.DelimitedSchema;
  import org.apache.apex.malhar.contrib.parser.DelimitedSchema.Field;
  import org.apache.apex.malhar.contrib.parser.Schema.FieldType;
  import org.apache.apex.malhar.lib.formatter.Formatter;
  
  import com.google.common.annotations.VisibleForTesting;
  
  import com.datatorrent.api.AutoMetric;
  import com.datatorrent.api.Context;
  import com.datatorrent.netlet.util.DTThrowable;
  
  /**
   * Operator that converts POJO to CSV string <br>
   * Assumption is that each field in the delimited data should map to a simple
   * java type.<br>
   * <br>
   * <b>Properties</b> <br>
   * <b>schema</b>:schema as a string specified in a json format as per
   * {@link DelimitedSchema}. Currently only Date constraint (fmt) is supported
   * <br>
   * <b>clazz</b>:Pojo class <br>
   * <b>Ports</b> <br>
   * <b>in</b>:input tuple as a POJO. Each tuple represents a record<br>
   * <b>out</b>:tuples are are converted to string are emitted on this port<br>
   * <b>err</b>:tuples that could not be converted are emitted on this port<br>
   *
   * @displayName CsvFormatter
   * @category Formatter
   * @tags pojo csv formatter
   * @since 3.2.0
   */
  @org.apache.hadoop.classification.InterfaceStability.Evolving
  public class CsvFormatter extends Formatter<String>
  {
  
    /**
     * Names of all the fields in the same order that would appear in output
     * records
     */
    private transient String[] nameMapping;
    /**
     * Cell processors are an integral part of reading and writing with Super CSV
     * they automate the data type conversions, and enforce constraints.
     */
    private transient CellProcessor[] processors;
    /**
     * Writing preferences that are passed through schema
     */
    private transient CsvPreference preference;
  
    /**
     * Contents of the schema.Schema is specified in a json format as per
     * {@link DelimitedSchema}
     */
    @NotNull
    private String schema;
    /**
     * Schema is read into this object to access fields
     */
    private transient DelimitedSchema delimitedParserSchema;
  
    /**
     * metric to keep count of number of tuples emitted on error port port
     */
    @AutoMetric
    private long errorTupleCount;
  
    /**
     * metric to keep count of number of tuples emitted on out port
     */
    @AutoMetric
    private long emittedObjectCount;
  
    /**
     * metric to keep count of number of tuples emitted on input port
     */
    @AutoMetric
    private long incomingTuplesCount;
  
    @Override
    public void beginWindow(long windowId)
    {
      super.beginWindow(windowId);
      errorTupleCount = 0;
      emittedObjectCount = 0;
      incomingTuplesCount = 0;
    }
  
    @Override
    public void setup(Context.OperatorContext context)
    {
      super.setup(context);
      delimitedParserSchema = new DelimitedSchema(schema);
      preference = new CsvPreference.Builder(delimitedParserSchema.getQuoteChar(),
          delimitedParserSchema.getDelimiterChar(), delimitedParserSchema.getLineDelimiter()).build();
      nameMapping = delimitedParserSchema.getFieldNames()
          .toArray(new String[delimitedParserSchema.getFieldNames().size()]);
      processors = getProcessor(delimitedParserSchema.getFields());
    }
  
    /**
     * Returns array of cellprocessors, one for each field
     */
    private CellProcessor[] getProcessor(List<Field> fields)
    {
      CellProcessor[] processor = new CellProcessor[fields.size()];
      int fieldCount = 0;
      for (Field field : fields) {
        if (field.getType() == FieldType.DATE) {
          String format = field.getConstraints().get(DelimitedSchema.DATE_FORMAT) == null ? null
              : (String)field.getConstraints().get(DelimitedSchema.DATE_FORMAT);
          processor[fieldCount++] = new Optional(new FmtDate(format == null ? "dd/MM/yyyy" : format));
        } else {
          processor[fieldCount++] = new Optional();
        }
      }
      return processor;
    }
  
    @Override
    public String convert(Object tuple)
    {
      incomingTuplesCount++;
      if (tuple == null) {
        errorTupleCount++;
        logger.error(" Null tuple", tuple);
        return null;
      }
      try {
        StringWriter stringWriter = new StringWriter();
        ICsvBeanWriter beanWriter = new CsvBeanWriter(stringWriter, preference);
        beanWriter.write(tuple, nameMapping, processors);
        beanWriter.flush();
        beanWriter.close();
        emittedObjectCount++;
        return stringWriter.toString();
      } catch (SuperCsvException e) {
        logger.error("Error while converting tuple {} {}", tuple, e.getMessage());
        errorTupleCount++;
      } catch (IOException e) {
        DTThrowable.rethrow(e);
      }
      return null;
    }
  
    /**
     * Get the schema
     *
     * @return schema
     */
    public String getSchema()
    {
      return schema;
    }
  
    /**
     * Set the schema
     *
     * @param schema
     */
    public void setSchema(String schema)
    {
      this.schema = schema;
    }
  
    @VisibleForTesting
    protected long getErrorTupleCount()
    {
      return errorTupleCount;
    }
  
    @VisibleForTesting
    protected long getEmittedObjectCount()
    {
      return emittedObjectCount;
    }
  
    @VisibleForTesting
    protected long getIncomingTuplesCount()
    {
      return incomingTuplesCount;
    }
  
    private static final Logger logger = LoggerFactory.getLogger(CsvFormatter.class);
  }
  