package us.codecraft.webmagic.model.fields;
   
   import java.lang.reflect.InvocationTargetException;
   import java.util.ArrayList;
   import java.util.List;
   
   import org.slf4j.Logger;
   
   import lombok.Getter;
  import us.codecraft.webmagic.model.FieldExtractor;
  import us.codecraft.webmagic.model.formatter.ObjectFormatter;
  
  public class MultipleField extends PageField {
     @Getter
     private List<String> fieldNames; 
  
     public MultipleField(List<String> fieldNames) {
        this.fieldNames = fieldNames;
     }
     
     public boolean operation(Object o, FieldExtractor fieldExtractor, Logger logger) throws IllegalAccessException, InvocationTargetException {
        if ((this.fieldNames == null || this.fieldNames.size() == 0) && fieldExtractor.isNotNull())
           return false;
        if (fieldExtractor.getObjectFormatter() != null) {
           List<Object> converted = this.convert(this.fieldNames, fieldExtractor.getObjectFormatter(), logger);
           setField(o, fieldExtractor, converted);
        }
        else
           setField(o, fieldExtractor, this.fieldNames);
        return true;
     }
  
     private List<Object> convert(List<String> values, ObjectFormatter objectFormatter, Logger logger) {
        List<Object> objects = new ArrayList<>();
        for (String value : values) {
            Object converted = this.convert(value, objectFormatter, logger);
            if (converted != null)
                objects.add(converted);
        }
        return objects;
    }
  }