package org.neo4j.driver.projection;
   
   import org.neo4j.driver.exception.Neo4jClientException;
   import org.neo4j.driver.v1.Record;
   
   import java.util.function.Function;
   
   /**
    * Abstract class for projection.
   * A projection is just a function that can be passed to a map.
   */
  abstract class Projection<T> implements Function<Record, T> {
  
      /**
       * Projection's type.
       */
      protected Class type;
  
      /**
       * Default constructor.
       *
       * @param type
       */
      public Projection(Class type) {
          this.type = type;
      }
  
      /**
       * Check if the given <code>record</code> has only one column.
       * if not, a {@link Neo4jClientException} is throw.
       *
       * @param record
       */
      protected void checkIfRecordHaveSingleValue(Record record) {
          if (record.size() > 1) {
              throw new Neo4jClientException("Record doesn't have a single column -> can't cast it to primitive object type");
          }
      }
  
  }