/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 2002-2006
 *      Sleepycat Software.  All rights reserved.
 *
 * $Id: DatabaseConfigTest.java,v 1.20 2006/04/05 18:03:39 mark Exp $
 */

package com.sleepycat.je;

import java.io.File;
import java.io.IOException;
import java.io.Serializable;
import java.util.Comparator;
import java.util.Set;

import junit.framework.TestCase;

import com.sleepycat.je.util.TestUtils;

/**
 * Basic database configuration testing.
 */
public class DatabaseConfigTest extends TestCase {
    private static final boolean DEBUG = false;
  
    private File envHome;
    private Environment env;

    public DatabaseConfigTest() {
        envHome = new File(System.getProperty(TestUtils.DEST_DIR));
    }

    public void setUp()
        throws IOException {

        TestUtils.removeLogFiles("Setup", envHome, false);
    }
    
    public void tearDown()
        throws Exception {

        try {
            /* Close in case we hit an exception and didn't close. */
            if (env != null) {
            	env.close();
            } 
        } catch (DatabaseException e) {
            /* Ok if already closed */
        }
        env = null; // for JUNIT, to reduce memory usage when run in a suite.
        TestUtils.removeLogFiles("TearDown", envHome, false);
    }

    /**
     * Test that we can retrieve a database configuration and that it clones
     * its configuration appropriately.
     */
    public void testConfig()
        throws Throwable {

        try {
            EnvironmentConfig envConfig = TestUtils.initEnvConfig();
            envConfig.setAllowCreate(true);
            env = new Environment(envHome, envConfig);

            /* 
             * Make sure that the database keeps its own copy of the
             * configuration object.
             */
            DatabaseConfig dbConfigA = new DatabaseConfig();
            dbConfigA.setAllowCreate(true);
            Database dbA = env.openDatabase(null, "foo", dbConfigA);

            /* Change the original dbConfig */
            dbConfigA.setAllowCreate(false);
            DatabaseConfig getConfig1 = dbA.getConfig();
            assertEquals(true, getConfig1.getAllowCreate());
            assertEquals(false, getConfig1.getSortedDuplicates());

            /* 
             * Change the retrieved config, ought to have no effect on what the
             * Database is storing.
             */
            getConfig1.setSortedDuplicates(true);
            DatabaseConfig getConfig2 = dbA.getConfig();
            assertEquals(false, getConfig2.getSortedDuplicates());
            
            dbA.close();
            env.close();
        } catch (Throwable t) {
            t.printStackTrace();
            throw t;
        }
    }

    public void testConfigMatching()
        throws Throwable {

        try {
	    /* DatabaseConfig matching. */

            DatabaseConfig confA = new DatabaseConfig();
            DatabaseConfig confB = new DatabaseConfig();

	    try {
		confA.validate(confB);
	    } catch (Exception E) {
		fail("expected valid match");
	    }

	    try {
		confB.validate(confA);
	    } catch (Exception E) {
		fail("expected valid match");
	    }

	    try {
		confA.validate(null); // uses the DEFAULT config
	    } catch (Exception E) {
		fail("expected valid match");
	    }

            confA.setReadOnly(true);
	    try {
		confA.validate(confB);
		fail("expected exception");
	    } catch (DatabaseException E) {
		// ok
	    }

            confA.setReadOnly(false);
	    confA.setSortedDuplicates(true);
	    try {
		confA.validate(confB);
		fail("expected exception");
	    } catch (DatabaseException E) {
		// ok
	    }
	    confA.setSortedDuplicates(false);

            confA.setOverrideBtreeComparator(true);
	    confA.setBtreeComparator(TestComparator.class);
            confB.setOverrideBtreeComparator(true);
	    confB.setBtreeComparator(TestComparator2.class);
	    try {
		confA.validate(confB);
		fail("expected exception");
	    } catch (DatabaseException E) {
		// ok
	    }
	    confA.setBtreeComparator((Class) null);
            confA.setOverrideBtreeComparator(false);
	    confB.setBtreeComparator((Class) null);
            confB.setOverrideBtreeComparator(false);

            confA.setOverrideDuplicateComparator(true);
	    confA.setDuplicateComparator(TestComparator.class);
            confB.setOverrideDuplicateComparator(true);
	    confB.setDuplicateComparator(TestComparator2.class);
	    try {
		confA.validate(confB);
		fail("expected exception");
	    } catch (DatabaseException E) {
		// ok
	    }

            /* Same tests as above but for serialized comparators. */

            confA.setOverrideBtreeComparator(true);
	    confA.setBtreeComparator(new TestSerialComparator());
            confB.setOverrideBtreeComparator(true);
	    confB.setBtreeComparator(new TestSerialComparator2());
	    try {
		confA.validate(confB);
		fail("expected exception");
	    } catch (DatabaseException E) {
		// ok
	    }
	    confA.setBtreeComparator((Comparator) null);
            confA.setOverrideBtreeComparator(false);
	    confB.setBtreeComparator((Comparator) null);
            confB.setOverrideBtreeComparator(false);

            confA.setOverrideDuplicateComparator(true);
	    confA.setDuplicateComparator(new TestSerialComparator());
            confB.setOverrideDuplicateComparator(true);
	    confB.setDuplicateComparator(new TestSerialComparator2());
	    try {
		confA.validate(confB);
		fail("expected exception");
	    } catch (DatabaseException E) {
		// ok
	    }

	    /* SecondaryConfig matching. */

            SecondaryConfig confC = new SecondaryConfig();
            SecondaryConfig confD = new SecondaryConfig();
	    confC.setKeyCreator(new SecKeyCreator1());
	    confD.setKeyCreator(new SecKeyCreator1());

	    try {
		confC.validate(confD);
	    } catch (Exception E) {
		E.printStackTrace();
		fail("expected valid match");
	    }

	    try {
		confD.validate(confC);
	    } catch (Exception E) {
		fail("expected valid match");
	    }

	    try {
		confC.validate(null);
		fail("expected exception");
	    } catch (DatabaseException E) {
		// ok
	    }

	    confD.setKeyCreator(new SecKeyCreator2());
	    try {
		confC.validate(confD);
		fail("expected exception");
	    } catch (DatabaseException E) {
		// ok
	    }
	    confD.setKeyCreator(new SecKeyCreator1());

	    confD.setMultiKeyCreator(new SecMultiKeyCreator1());
	    try {
		confC.validate(confD);
		fail("expected exception");
	    } catch (DatabaseException E) {
		// ok
	    }
	    confD.setMultiKeyCreator(null);

	    confC.setForeignKeyDeleteAction(ForeignKeyDeleteAction.NULLIFY);
	    try {
		confC.validate(confD);
		fail("expected exception");
	    } catch (DatabaseException E) {
		// ok
	    }
	    confC.setForeignKeyDeleteAction(ForeignKeyDeleteAction.ABORT);

	    confC.setForeignKeyNullifier(new ForeignKeyNullifier1());
	    try {
		confC.validate(confD);
		fail("expected exception");
	    } catch (DatabaseException E) {
		// ok
	    }
	    confC.setForeignKeyNullifier(null);

	    confC.setForeignMultiKeyNullifier(new ForeignMultiKeyNullifier1());
	    try {
		confC.validate(confD);
		fail("expected exception");
	    } catch (DatabaseException E) {
		// ok
	    }
	    confC.setForeignMultiKeyNullifier(null);

	    confC.setImmutableSecondaryKey(true);
	    try {
		confC.validate(confD);
		fail("expected exception");
	    } catch (DatabaseException E) {
		// ok
	    }
	    confC.setImmutableSecondaryKey(false);
        } catch (Throwable t) {
            t.printStackTrace();
            throw t;
        }
    }

    /**
     * Make sure we can instantiate a comparator at the time it's set.
     */
    public void testComparator()
        throws Throwable {

        try {
            /* Can't be instantiated, a nested class */
            try {
                DatabaseConfig config = new DatabaseConfig();
                config.setBtreeComparator(BadComparator1.class);
                fail("Comparator shouldn't be instantiated");
            } catch (IllegalArgumentException e) {
                /* Expected. */
                if (DEBUG) {
                    System.out.println(e);
                }
            }

            /* No zero-parameter constructor */
            try {
                DatabaseConfig config = new DatabaseConfig();
                config.setBtreeComparator(BadComparator2.class);
                fail("Comparator shouldn't be instantiated");
            } catch (IllegalArgumentException e) {
                /* Expected. */
                if (DEBUG) {
                    System.out.println(e);
                }
            }

            /* Can't be serialized, not serializable */
            try {
                DatabaseConfig config = new DatabaseConfig();
                config.setBtreeComparator(new BadSerialComparator1());
                fail("Comparator shouldn't be instantiated");
            } catch (IllegalArgumentException e) {
                /* Expected. */
                if (DEBUG) {
                    System.out.println(e);
                }
            }

            /* Can't be serialized, contains non-serializable field */
            try {
                DatabaseConfig config = new DatabaseConfig();
                config.setBtreeComparator(new BadSerialComparator2());
                fail("Comparator shouldn't be instantiated");
            } catch (IllegalArgumentException e) {
                /* Expected. */
                if (DEBUG) {
                    System.out.println(e);
                }
            }

            /* Valid comparators */
            DatabaseConfig config = new DatabaseConfig();
            config.setBtreeComparator(TestComparator.class);
            config.setBtreeComparator(TestComparator2.class);
            config.setBtreeComparator(new TestSerialComparator());
            config.setBtreeComparator(new TestSerialComparator2());

        } catch (Throwable t) {
            t.printStackTrace();
            throw t;
        }
    }

    /**
     * Test that any conflicts between configuration object settings and the
     * underlying impl object are detected.
     */
    public void testConfigConfict() 
        throws Throwable {
        
        try {
            EnvironmentConfig envConfig = TestUtils.initEnvConfig();
            envConfig.setAllowCreate(true);
            env = new Environment(envHome, envConfig);

            /*
             * Test conflicts of duplicate allowed configuration.
             */

            /* 1a. Create allowing duplicates. */
            DatabaseConfig firstConfig = new DatabaseConfig();
            firstConfig.setAllowCreate(true);
            firstConfig.setSortedDuplicates(true);
            Database firstHandle = env.openDatabase(null, "fooDups",
                                                    firstConfig);
            /* 1b. Try to open w/no duplicates. */
            DatabaseConfig secondConfig = new DatabaseConfig();
            secondConfig.setSortedDuplicates(false);
            try {
                    env.openDatabase(null, "fooDups", secondConfig);
                fail("Conflict in duplicates allowed should be detected.");
            } catch (DatabaseException e) {
            }
            
            firstHandle.close();
            env.removeDatabase(null, "fooDups");

            /* 2a. Create dis-allowing duplicates. */
            firstConfig.setSortedDuplicates(false);
            firstHandle = env.openDatabase(null, "fooDups", firstConfig);
            /* 2b. Try to open w/duplicates. */
            secondConfig.setSortedDuplicates(true);
            try {
                    env.openDatabase(null, "fooDups", secondConfig);
                fail("Conflict in duplicates allowed should be detected.");
            } catch (DatabaseException e) {
            }
            firstHandle.close();

            /*
             * Test conflicts of read only. If the environment is read/write
             * we should be able to open handles in read only or read/write
             * mode. If the environment is readonly, the database handles 
             * must also be read only.
             */
            DatabaseConfig readOnlyConfig = new DatabaseConfig();
            readOnlyConfig.setReadOnly(true);
            Database roHandle = env.openDatabase(null, "fooDups",
                                                 readOnlyConfig);
            roHandle.close();

            /* Open the environment in read only mode. */
            env.close();
            envConfig = TestUtils.initEnvConfig();
            envConfig.setReadOnly(true);
            env = new Environment(envHome, envConfig);
            
            /* Open a readOnly database handle, should succeed */
            roHandle = env.openDatabase(null, "fooDups",
                                        readOnlyConfig);
            roHandle.close();

            /* Open a read/write database handle, should succeed. */
            try {
                env.openDatabase(null, "fooDups", null);
                fail("Should not be able to open read/write");
            } catch (DatabaseException e) {
                if (DEBUG) {
                    System.out.println(e);
                }
            }
            env.close();

            /*
             * Check comparator changes.
             */
            /* 1a. Open w/a null comparator */
            env = new Environment(envHome, null);
            firstConfig = new DatabaseConfig();
            firstConfig.setAllowCreate(true);
            firstHandle = env.openDatabase(null,
                                           "fooComparator",
                                           firstConfig);
            DatabaseConfig firstRetrievedConfig = firstHandle.getConfig();
            assertEquals(null, firstRetrievedConfig.getBtreeComparator());
            assertEquals(null, firstRetrievedConfig.getDuplicateComparator());

            /* 
             * 1b. Open a db w/a different comparator, shouldn't take effect
             * because override is not set.
             */
            secondConfig = new DatabaseConfig();
            Comparator btreeComparator = new TestComparator();
            Comparator dupComparator = new TestComparator();
            secondConfig.setBtreeComparator(btreeComparator.getClass());
            secondConfig.setDuplicateComparator(dupComparator.getClass());
            Database secondHandle =
		env.openDatabase(null, "fooComparator", secondConfig);
            DatabaseConfig retrievedConfig = secondHandle.getConfig();
            assertEquals(null, retrievedConfig.getBtreeComparator());
            assertEquals(null, retrievedConfig.getDuplicateComparator());
            secondHandle.close();

            /* Same as above but with a serialized comparator. */
            secondConfig = new DatabaseConfig();
            btreeComparator = new TestSerialComparator();
            dupComparator = new TestSerialComparator();
            secondConfig.setBtreeComparator(btreeComparator);
            secondConfig.setDuplicateComparator(dupComparator);
            secondHandle =
		env.openDatabase(null, "fooComparator", secondConfig);
            retrievedConfig = secondHandle.getConfig();
            assertEquals(null, retrievedConfig.getBtreeComparator());
            assertEquals(null, retrievedConfig.getDuplicateComparator());
            secondHandle.close();

            /* 1c. Allow override */
            secondConfig.setOverrideBtreeComparator(true);
            secondConfig.setOverrideDuplicateComparator(true);
            btreeComparator = new TestComparator();
            dupComparator = new TestComparator();
            secondConfig.setBtreeComparator(btreeComparator.getClass());
            secondConfig.setDuplicateComparator(dupComparator.getClass());
            secondHandle = env.openDatabase(null,
                                            "fooComparator",
                                            secondConfig);

            retrievedConfig = secondHandle.getConfig();
            assertEquals(btreeComparator.getClass(),
                         retrievedConfig.getBtreeComparator().getClass());
            assertEquals(dupComparator.getClass(),
                         retrievedConfig.getDuplicateComparator().getClass());
            secondHandle.close();

            /* Same as above but with a serialized comparator. */
            secondConfig.setOverrideBtreeComparator(true);
            secondConfig.setOverrideDuplicateComparator(true);
            btreeComparator = new TestSerialComparator();
            dupComparator = new TestSerialComparator();
            secondConfig.setBtreeComparator(btreeComparator);
            secondConfig.setDuplicateComparator(dupComparator);
            secondHandle = env.openDatabase(null,
                                            "fooComparator",
                                            secondConfig);

            retrievedConfig = secondHandle.getConfig();
            assertEquals(btreeComparator,
                         retrievedConfig.getBtreeComparator());
            assertEquals(dupComparator,
                         retrievedConfig.getDuplicateComparator());
            secondHandle.close();

            firstHandle.close();
            env.close();
        } catch (Throwable t) {
            t.printStackTrace();
            env.close();
            throw t;
        }
    }

    public void testIsTransactional()
        throws Throwable {

        try {
            /* Open environment in transactional mode.*/
            EnvironmentConfig envConfig = TestUtils.initEnvConfig();
            envConfig.setTransactional(true);
            envConfig.setAllowCreate(true);
            env = new Environment(envHome, envConfig);

            /* Create a db, open transactionally with implied auto-commit. */
            DatabaseConfig dbConfig = new DatabaseConfig();
            dbConfig.setAllowCreate(true);
            dbConfig.setTransactional(true);
            Database myDb = env.openDatabase(null, "testDB", dbConfig);
            assertTrue(myDb.isTransactional());
            assertTrue(myDb.getConfig().getTransactional());
            myDb.close();

            /* Open an existing db, can open it non-transactionally. */
            dbConfig.setTransactional(false);
            myDb = env.openDatabase(null, "testDB", null);
            assertFalse(myDb.isTransactional());
            assertFalse(myDb.getConfig().getTransactional());
            myDb.close();

            /* Open another db, pass an explicit transaction. */
            dbConfig.setTransactional(true);
            Transaction txn = env.beginTransaction(null, null);
            myDb = env.openDatabase(txn, "testDB2", dbConfig);
            assertTrue(myDb.isTransactional());
            assertTrue(myDb.getConfig().getTransactional());

            DatabaseEntry key = new DatabaseEntry();
            DatabaseEntry data = new DatabaseEntry();
            key.setData(TestUtils.getTestArray(0));
            data.setData(TestUtils.getTestArray(0));
            try {
                myDb.put(null, key, data);
            } catch (DatabaseException DBE) {
                fail("didn't expect DatabaseException, implied autocommit");
            }

            key.setData(TestUtils.getTestArray(1));
            data.setData(TestUtils.getTestArray(1));
            try {
                myDb.put(txn, key, data);
            } catch (DatabaseException DBE) {
                fail("didn't expect DatabaseException with txn passed");
            }

            try {
                myDb.get(txn, key, data, LockMode.DEFAULT);
            } catch (DatabaseException DBE) {
                fail("didn't expect DatabaseException with txn passed");
            }

            txn.commit();

            try {
                myDb.get(null, key, data, LockMode.DEFAULT);
            } catch (DatabaseException DBE) {
                fail("didn't expect DatabaseException because no txn passed");
            }

            myDb.close();

            env.close();
        } catch (Throwable t) {
            t.printStackTrace();
            throw t;
        }
    }

    public void testOpenReadOnly()
        throws Throwable {

        try {
            EnvironmentConfig envConfig = TestUtils.initEnvConfig();
            envConfig.setTransactional(true);
            envConfig.setAllowCreate(true);
            env = new Environment(envHome, envConfig);

            DatabaseEntry key = new DatabaseEntry();
            DatabaseEntry data = new DatabaseEntry();

            Transaction txn = env.beginTransaction(null, null);
            DatabaseConfig dbConfig = new DatabaseConfig();
            dbConfig.setTransactional(true);
            dbConfig.setAllowCreate(true);
            Database myDb = env.openDatabase(txn, "testDB2", dbConfig);

            key.setData(TestUtils.getTestArray(0));
            data.setData(TestUtils.getTestArray(0));
            try {
                myDb.put(txn, key, data);
            } catch (DatabaseException DBE) {
                fail("unexpected DatabaseException during put");
            }

            txn.commit();
            myDb.close();

            dbConfig = new DatabaseConfig();
            dbConfig.setTransactional(true);
            dbConfig.setReadOnly(true);
            txn = env.beginTransaction(null, null);
            myDb = env.openDatabase(txn, "testDB2", dbConfig);
            assertTrue(myDb.isTransactional());
            assertTrue(myDb.getConfig().getTransactional());

            key.setData(TestUtils.getTestArray(0));
            data.setData(TestUtils.getTestArray(0));
            try {
                myDb.put(txn, key, data);
                fail("expected DatabaseException because open RDONLY");
            } catch (DatabaseException DBE) {
            }

            key.setData(TestUtils.getTestArray(0));
            data.setData(TestUtils.getTestArray(0));
            assertEquals(OperationStatus.SUCCESS,
                         myDb.get(txn, key, data, LockMode.DEFAULT));

            Cursor cursor = myDb.openCursor(txn, null);

            assertEquals(OperationStatus.SUCCESS,
                         cursor.getFirst(key, data, LockMode.DEFAULT));

            try {
                cursor.delete();
                fail("expected Exception from delete on RD_ONLY db");
            } catch (DatabaseException DBE) {
            }

            key.setData(TestUtils.getTestArray(1));
            data.setData(TestUtils.getTestArray(1));
            try {
                myDb.put(txn, key, data);
                fail("expected DatabaseException because open RDONLY");
            } catch (DatabaseException DBE) {
            }

	    cursor.close();
            txn.commit();
            myDb.close();

            env.close();
        } catch (Throwable t) {
            t.printStackTrace();
            throw t;
        }
    }

    /**
     * Test exclusive creation.
     */
    public void testExclusive()
        throws Throwable {

        try {
            EnvironmentConfig envConfig = TestUtils.initEnvConfig();

            /* 
             * Make sure that the database keeps its own copy of the
             * configuration object.
             */
            envConfig.setAllowCreate(true);
            env = new Environment(envHome, envConfig);
            DatabaseConfig dbConfig = new DatabaseConfig();
            dbConfig.setAllowCreate(true);
            dbConfig.setExclusiveCreate(true);

            /* Should succeed and create the database. */
            Database dbA = env.openDatabase(null, "foo", dbConfig);
            dbA.close();
                                            
            /* Should not succeed, because the database exists. */
            try {
                env.openDatabase(null, "foo", dbConfig);
                fail("Database already exists");
            } catch (DatabaseException e) {
            }
            env.close();
        } catch (Throwable t) {
            t.printStackTrace();
            throw t;
        }
    }

    /*
     * This Comparator can't be instantiated because it's private and not
     * static.
     */
    private class BadComparator1 implements Comparator {
        public BadComparator1(int foo) {
        }
        
        public int compare(Object o1, Object o2) {
            return 0;
        }
    }

    /*
     * This Comparator can't be instantiated because it doesn't have zero
     * parameter constructor.
     */
    public static class BadComparator2 implements Comparator {
        public BadComparator2(int i) {
        }

        public int compare(Object o1, Object o2) {
            return 0;
        }
    }    

    /*
     * OK comparator for setting comparators.
     */
    public static class TestComparator implements Comparator {
        public TestComparator() {
        }

        public int compare(Object o1, Object o2) {
            return 0;
        }
    }

    /*
     * OK comparator for setting comparators.
     */
    public static class TestComparator2 implements Comparator {
        public TestComparator2() {
        }

        public int compare(Object o1, Object o2) {
            return 0;
        }
    }

    /*
     * This Comparator can't be serialized because it's not serializable.
     */
    public class BadSerialComparator1 implements Comparator {

        public BadSerialComparator1() {
        }
        
        public int compare(Object o1, Object o2) {
            return 0;
        }
    }

    /*
     * This Comparator can't be serialized because it contains a reference to
     * an object that's not serializable.
     */
    public class BadSerialComparator2 implements Comparator, Serializable {

        private BadSerialComparator1 o = new BadSerialComparator1();

        public BadSerialComparator2() {
        }
        
        public int compare(Object o1, Object o2) {
            return 0;
        }
    }

    /*
     * OK comparator for setting comparators -- private class, private
     * constructor, and serializable fields are allowed.
     */
    private static class TestSerialComparator
        implements Comparator, Serializable {

        private String s = "sss";

        private TestSerialComparator() {
        }

        public int compare(Object o1, Object o2) {
            return 0;
        }

        public boolean equals(Object other) {
            TestSerialComparator o = (TestSerialComparator) other;
            return s.equals(o.s);
        }
    }

    /*
     * OK comparator for setting comparators.
     */
    public static class TestSerialComparator2
        implements Comparator, Serializable {

        public int compare(Object o1, Object o2) {
            return 0;
        }
    }

    public static class SecKeyCreator1 implements SecondaryKeyCreator {
	public boolean createSecondaryKey(SecondaryDatabase secondary,
					  DatabaseEntry key,
					  DatabaseEntry data,
					  DatabaseEntry result)
	    throws DatabaseException {

	    return true;
	}

	public boolean equals(Object o) {
	    if (o == null) {
		return false;
	    }
	    return (o.getClass() == getClass());
	}
    }

    public static class SecKeyCreator2 implements SecondaryKeyCreator {
	public boolean createSecondaryKey(SecondaryDatabase secondary,
					  DatabaseEntry key,
					  DatabaseEntry data,
					  DatabaseEntry result)
	    throws DatabaseException {

	    return true;
	}

	public boolean equals(Object o) {
	    if (o == null) {
		return false;
	    }
	    return (o.getClass() == getClass());
	}
    }

    public static class SecMultiKeyCreator1
        implements SecondaryMultiKeyCreator {
	public void createSecondaryKeys(SecondaryDatabase secondary,
					DatabaseEntry key,
					DatabaseEntry data,
					Set results)
	    throws DatabaseException {
	}

	public boolean equals(Object o) {
	    if (o == null) {
		return false;
	    }
	    return (o.getClass() == getClass());
	}
    }

    public static class ForeignKeyNullifier1 implements ForeignKeyNullifier {
	public boolean nullifyForeignKey(SecondaryDatabase secondary,
					 DatabaseEntry data)
	    throws DatabaseException {

	    return true;
	}
    }

    public static class ForeignMultiKeyNullifier1
        implements ForeignMultiKeyNullifier {
	public boolean nullifyForeignKey(SecondaryDatabase secondary,
					 DatabaseEntry key,
					 DatabaseEntry data,
					 DatabaseEntry secKey)
	    throws DatabaseException {

	    return true;
	}
    }
}
