package com.sleepycat.bind.tuple;
import de.ovgu.cide.jakutil.*;
/** 
 * A marshalling interface implemented by entity classes that represent keys as
 * tuples. Since <code>MarshalledTupleKeyEntity</code> objects are
 * instantiated using Java deserialization, no particular constructor is
 * required by classes that implement this interface.
 * <p>
 * Note that a marshalled tuple key extractor is somewhat less efficient than a
 * non-marshalled key tuple extractor because more conversions are needed. A
 * marshalled key extractor must convert the entry to an object in order to
 * extract the key fields, while an unmarshalled key extractor does not.
 * </p>
 * @author Mark Hayes
 * @see TupleTupleMarshalledBinding
 * @see com.sleepycat.bind.serial.TupleSerialMarshalledBinding
 */
public interface MarshalledTupleKeyEntity {
  /** 
 * Extracts the entity's primary key and writes it to the key output.
 * @param keyOutputis the output tuple.
 */
  void marshalPrimaryKey(  TupleOutput keyOutput);
  /** 
 * Completes construction of the entity by setting its primary key from the
 * stored primary key.
 * @param keyInputis the input tuple.
 */
  void unmarshalPrimaryKey(  TupleInput keyInput);
  /** 
 * Extracts the entity's secondary key and writes it to the key output.
 * @param keyNameidentifies the secondary key.
 * @param keyOutputis the output tuple.
 * @return true if a key was created, or false to indicate that the key is
 * not present.
 */
  boolean marshalSecondaryKey(  String keyName,  TupleOutput keyOutput);
  /** 
 * Clears the entity's secondary key fields for the given key name.
 * <p>
 * The specified index key should be changed by this method such that{@link #marshalSecondaryKey} for the same key name will return false.
 * Other fields in the data object should remain unchanged.
 * </p>
 * <!-- begin JE only -->
 * <p>
 * If {@link com.sleepycat.je.ForeignKeyDeleteAction#NULLIFY} was specified
 * when opening the secondary database, this method is called when the
 * entity for this foreign key is deleted. If NULLIFY was not specified,
 * this method will not be called and may always return false.
 * </p>
 * <!-- end JE only -->
 * @param keyNameidentifies the secondary key.
 * @return true if the key was cleared, or false to indicate that the key is
 * not present and no change is necessary.
 */
  boolean nullifyForeignKey(  String keyName);
}
