/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 2000, 2015 Oracle and/or its affiliates. All rights reserved.
*
*/
package com.sleepycat.bind.tuple;
import com.sleepycat.db.DatabaseEntry;
import com.sleepycat.db.ForeignKeyNullifier;
import com.sleepycat.db.SecondaryDatabase;
import com.sleepycat.db.SecondaryKeyCreator;
/**
* An abstract key creator that uses a tuple key and a tuple data entry. This
* class takes care of converting the key and data entry to/from {@link
* TupleInput} and {@link TupleOutput} objects.
* The following abstract method must be implemented by a concrete subclass
* to create the index key using these objects
* <ul>
* <li> {@link #createSecondaryKey(TupleInput,TupleInput,TupleOutput)} </li>
* </ul>
* <p>If {@link com.sleepycat.db.ForeignKeyDeleteAction#NULLIFY} was
* specified when opening the secondary database, the following method must be
* overridden to nullify the foreign index key. If NULLIFY was not specified,
* this method need not be overridden.</p>
* <ul>
* <li> {@link #nullifyForeignKey(TupleInput,TupleOutput)} </li>
* </ul>
* <p>If {@link com.sleepycat.db.ForeignKeyDeleteAction#NULLIFY} was
* specified when creating the secondary, 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>
*
* @author Mark Hayes
*/
public abstract class TupleTupleKeyCreator<E> extends TupleBase<E>
implements SecondaryKeyCreator, ForeignKeyNullifier {
/**
* Creates a tuple-tuple key creator.
*/
public TupleTupleKeyCreator() {
}
// javadoc is inherited
public boolean createSecondaryKey(SecondaryDatabase db,
DatabaseEntry primaryKeyEntry,
DatabaseEntry dataEntry,
DatabaseEntry indexKeyEntry) {
TupleOutput output = getTupleOutput(null);
TupleInput primaryKeyInput = entryToInput(primaryKeyEntry);
TupleInput dataInput = entryToInput(dataEntry);
if (createSecondaryKey(primaryKeyInput, dataInput, output)) {
outputToEntry(output, indexKeyEntry);
return true;
} else {
return false;
}
}
// javadoc is inherited
public boolean nullifyForeignKey(SecondaryDatabase db,
DatabaseEntry dataEntry) {
TupleOutput output = getTupleOutput(null);
if (nullifyForeignKey(entryToInput(dataEntry), output)) {
outputToEntry(output, dataEntry);
return true;
} else {
return false;
}
}
/**
* Creates the index key from primary key tuple and data tuple.
*
* @param primaryKeyInput is the {@link TupleInput} for the primary key
* entry.
*
* @param dataInput is the {@link TupleInput} for the data entry.
*
* @param indexKeyOutput is the destination index key tuple.
*
* @return true if a key was created, or false to indicate that the key is
* not present.
*/
public abstract boolean createSecondaryKey(TupleInput primaryKeyInput,
TupleInput dataInput,
TupleOutput indexKeyOutput);
/**
* Clears the index key in the tuple data entry. The dataInput should be
* read and then written to the dataOutput, clearing the index key in the
* process.
*
* <p>The secondary key should be output or removed by this method such
* that {@link #createSecondaryKey} will return false. Other fields in the
* data object should remain unchanged.</p>
*
* @param dataInput is the {@link TupleInput} for the data entry.
*
* @param dataOutput is the destination {@link TupleOutput}.
*
* @return true if the key was cleared, or false to indicate that the key
* is not present and no change is necessary.
*/
public boolean nullifyForeignKey(TupleInput dataInput,
TupleOutput dataOutput) {
return false;
}
}