b2i.java

derby database source code.good for you.

	** Methods of B2I.
	*/

	/**
	Create an empty secondary index b-tree, using the generic b-tree to do the
    generic part of the creation process.

    This routine opens the newly created container, adds a single page, and
    makes this page the root by inserting a LeafControlRow onto this page
    at slot 0 and marking in that control row that the page is a root page.

    The following properties are specific to the b-tree secondary index:
    <UL>
    <LI> "baseConglomerateId" (integer).  The conglomerate id of the base
    conglomerate is never actually accessed by the b-tree secondary
    index implementation, it only serves as a namespace for row locks.
    This property is required.
    <LI> "rowLocationColumn" (integer).  The zero-based index into the row which
    the b-tree secondary index will assume holds a @see RowLocation of
    the base row in the base conglomerate.  This value will be used
    for acquiring locks.  In this implementation RowLocationColumn must be 
    the last key column.
    This property is required.
    </UL>

    A secondary index i (a, b) on table t (a, b, c) would have rows
    which looked like (a, b, row_location).  baseConglomerateId is set to the
    conglomerate id of t.  rowLocationColumns is set to 2.  allowsDuplicates
    would be set to false, @see BTree#create.  To create a unique
    secondary index set uniquenessColumns to 2, this means that the btree
    code will compare the key values but not the row id when determing
    uniqueness.  To create a nonunique secondary index set uniquenessColumns
    to 3, this would mean that the uniqueness test would include the row
    location and since all row locations will be unique  all rows inserted 
    into the index will be differentiated (at least) by row location.  

	@see BTree#create

	@exception StandardException Standard exception policy.
	**/
	public void create(
    TransactionManager      xact_manager,
    int                     segmentId, 
    long                    input_conglomid, 
    DataValueDescriptor[]	template, 
	ColumnOrdering[]	    columnOrder,
    Properties              properties,
	int                     temporaryFlag)
		throws StandardException
	{
        String      property_value = null;
        Transaction rawtran        = xact_manager.getRawStoreXact();

        if (properties == null)
        {
            throw(StandardException.newException(
                    SQLState.BTREE_PROPERTY_NOT_FOUND, PROPERTY_BASECONGLOMID));
        }

        // Get baseConglomerateId //
        property_value = properties.getProperty(PROPERTY_BASECONGLOMID);
        if (property_value == null)
        {
            throw(StandardException.newException(
                    SQLState.BTREE_PROPERTY_NOT_FOUND, PROPERTY_BASECONGLOMID));
        }

        if (SanityManager.DEBUG)
        {
			if (property_value == null)
            	SanityManager.THROWASSERT(
                	PROPERTY_BASECONGLOMID +
					"property not passed to B2I.create()");
        }

        baseConglomerateId = Long.parseLong(property_value);

        // Get rowLocationColumn //
        property_value = properties.getProperty(PROPERTY_ROWLOCCOLUMN);

        if (SanityManager.DEBUG)
        {
			if (property_value == null)
            	SanityManager.THROWASSERT(
                	PROPERTY_ROWLOCCOLUMN +
					"property not passed to B2I.create()");
        }

        if (property_value == null)
        {
            throw(StandardException.newException(
                    SQLState.BTREE_PROPERTY_NOT_FOUND, PROPERTY_BASECONGLOMID));
        }

        rowLocationColumn = Integer.parseInt(property_value);

        // Currently the row location column must be the last column (makes)
        // comparing the columns in the index easier.
        if (SanityManager.DEBUG)
        {
            SanityManager.ASSERT(rowLocationColumn == template.length - 1, 
                "rowLocationColumn is not the last column in the index");
            SanityManager.ASSERT(
                template[rowLocationColumn] instanceof 
                    RowLocation);

            // There must be at least one key column
			if (rowLocationColumn < 1)
            	SanityManager.THROWASSERT(
					"rowLocationColumn (" + rowLocationColumn +
					") expected to be >= 1");
        }


		/* covert the sorting order information into a boolean array map.
		 * If the sorting order for the columns is not provided, we
		 * assign the default as Ascending Order.
		 * array length is equla to template length , because column order
		 * length changes wther it is unique is non unique. store assumes
		 * template length arrays. So , we make  template length array and make
		 * the last column as ascending instead of having lot of execeptions code.
		 */
		
		ascDescInfo = new boolean[template.length];
		for (int i=0 ; i < ascDescInfo.length; i++)
		{
			if (columnOrder != null && i < columnOrder.length)
				ascDescInfo[i] = columnOrder[i].getIsAscending();
			else
				ascDescInfo[i] = true;  // default values - ascending order
		}

		// Do the generic part of creating the b-tree.
		super.create(rawtran, segmentId, input_conglomid, template, properties, getTypeFormatId(), temporaryFlag);

        // open the base conglomerate - to get the lock
        ConglomerateController base_cc = 
            xact_manager.openConglomerate(
                baseConglomerateId,
                false,
                TransactionController.OPENMODE_FOR_LOCK_ONLY, 
                TransactionController.MODE_TABLE,
                TransactionController.ISOLATION_SERIALIZABLE);
        
        OpenBTree open_btree = new OpenBTree();

        BTreeLockingPolicy b2i_locking_policy = 
            new B2ITableLocking3(
                rawtran,
                TransactionController.MODE_TABLE,
                rawtran.newLockingPolicy(
                    LockingPolicy.MODE_CONTAINER,
                    TransactionController.ISOLATION_SERIALIZABLE, true), base_cc, open_btree);


        // The following call will "open" the new btree.  Create is
        // an interesting case.  What we really want is read only table lock
        // on the base conglomerate and update locks on the index.  For now
        // just get the update lock on the base table, this is done by the
        // lockTable() call made by base class.

        open_btree.init(
            (TransactionManager) xact_manager,  // current user xact
            (TransactionManager) xact_manager,  // current xact
            (ContainerHandle) null,     // have init open the container.
            rawtran, 
            false,
            (ContainerHandle.MODE_FORUPDATE),
            TransactionController.MODE_TABLE,
            b2i_locking_policy,         // get table level lock.
            this,                       
            (LogicalUndo) null,         // no logical undo necessary, as 
                                        // initEmptyBtree()
                                        // work will be done single user and
                                        // rows will not move.
            (DynamicCompiledOpenConglomInfo) null);
                                        
		// Open the newly created container, and insert the first control row.
        LeafControlRow.initEmptyBtree(open_btree);

        open_btree.close();

        base_cc.close();
	}



	/*
	** Methods of Conglomerate
	*/

    /**
     * Retrieve the maximum value row in an ordered conglomerate.
     * <p>
     * Returns true and fetches the rightmost row of an ordered conglomerate 
     * into "fetchRow" if there is at least one row in the conglomerate.  If
     * there are no rows in the conglomerate it returns false.
     * <p>
     * Non-ordered conglomerates will not implement this interface, calls
     * will generate a StandardException.
     * <p>
     * RESOLVE - this interface is temporary, long term equivalent (and more) 
     * functionality will be provided by the openBackwardScan() interface.  
     *
	 * @param xact_manager    The TransactionController under which this 
     *                        operation takes place.
     *
	 * @param conglomId       The identifier of the conglomerate
	 *                        to open the scan for.
     *
	 * @param open_mode       Specifiy flags to control opening of table.  
     *                        OPENMODE_FORUPDATE - if set open the table for
     *                        update otherwise open table shared.
     * @param lock_level      One of (MODE_TABLE, MODE_RECORD, or MODE_NONE).
     *
     * @param isolation_level The isolation level to lock the conglomerate at.
     *                        One of (ISOLATION_READ_COMMITTED or ISOLATION_SERIALIZABLE).
     *
	 * @param scanColumnList  A description of which columns to return from 
     *                        every fetch in the scan.  template, 
     *                        and scanColumnList work together
     *                        to describe the row to be returned by the scan - 
     *                        see RowUtil for description of how these three 
     *                        parameters work together to describe a "row".
     *
     * @param fetchRow        The row to retrieve the maximum value into.
     *
	 * @return boolean indicating if a row was found and retrieved or not.
     *
	 * @exception  StandardException  Standard exception policy.
     **/
	public boolean fetchMaxOnBTree(
    TransactionManager      xact_manager,
    Transaction             rawtran,
    long                    conglomId,
    int                     open_mode,
    int                     lock_level,
    LockingPolicy           locking_policy,
    int                     isolation_level,
    FormatableBitSet                 scanColumnList,
    DataValueDescriptor[]   fetchRow)
        throws StandardException
    {
        boolean row_exists;

        // row level locking implementation.

        // RESOLVE (revisit implementation after all the Xena rowlocking
        // changes have been made).  Can probably come up with single
        // path implementation.
        
        // Create a new b-tree secondary index scan.
        B2IMaxScan b2is = new B2IMaxScan();

        // Initialize it.
        b2is.init(
            xact_manager, 
            rawtran, 
            open_mode,
            lock_level,
            locking_policy,
            isolation_level,
            true /* get locks on base table as part of open */,
            scanColumnList,
            this, 
            new B2IUndo());

        row_exists = b2is.fetchMax(fetchRow);

        b2is.close();

        return(row_exists);
    }


	/**
	Bulk Load a B-tree secondary index.

	@see Conglomerate#load
	@exception StandardException Standard Cloudscape Error policy.
	raise SQLState.STORE_CONGLOMERATE_DUPLICATE_KEY_EXCEPTION if a duplicate 
    key is detected in the load.
	**/

	public long load(
	TransactionManager      xact_manager,
	boolean                 createConglom,
	RowLocationRetRowSource rowSource)
		 throws StandardException
	{
        long num_rows_loaded = 0;
		B2IController b2ic = new B2IController();

		try
		{
            int open_mode = TransactionController.OPENMODE_FORUPDATE;

            if (createConglom)
            {
                open_mode |=
                    (ContainerHandle.MODE_UNLOGGED |
                     ContainerHandle.MODE_CREATE_UNLOGGED);
            }

            // Do the actual open of the container in the super class.
            b2ic.init(
                xact_manager,                    // current transaction   
                xact_manager.getRawStoreXact(),  // current raw store xact
                false,                           // Not holdable
                open_mode,
                TransactionController.MODE_TABLE,
                xact_manager.getRawStoreXact().newLockingPolicy(
                    LockingPolicy.MODE_CONTAINER,
                    TransactionController.ISOLATION_SERIALIZABLE, true),
                true,
                this, 
                new B2IUndo(),
                (B2IStaticCompiledInfo) null,
                (DynamicCompiledOpenConglomInfo) null);

            num_rows_loaded = b2ic.load(xact_manager, createConglom, rowSource);

		}
		finally
		{
			b2ic.close();
		}

        return(num_rows_loaded);
	}

	/**
	Open a b-tree controller.
	@see Conglomerate#open

	@exception StandardException Standard exception policy.
	**/
	public ConglomerateController open(
    TransactionManager              xact_manager,
    Transaction                     rawtran, 
    boolean                         hold,
    int                             open_mode,
    int                             lock_level,
    LockingPolicy                   locking_policy,
    StaticCompiledOpenConglomInfo   static_info,
    DynamicCompiledOpenConglomInfo  dynamic_info)
		throws StandardException
	{
		// Create a new b-tree secondary index controller.
		B2IController b2ic = new B2IController();

		// Do the actual open of the container in the super class.
		b2ic.init(