private DeleteResult processDelete()

in mavibot/src/main/java/org/apache/directory/mavibot/btree/PersistedBTree.java [325:429]
50 lines of code
9 McCabe index (conditional complexity)

    private DeleteResult<K, V> processDelete( K key, V value, long revision ) throws IOException
    {
        // Get the current B-tree header, and delete the value from it
        BTreeHeader<K, V> btreeHeader = getBTreeHeader( getName() );

        // Try to delete the entry starting from the root page. Here, the root
        // page may be either a Node or a Leaf
        DeleteResult<K, V> result = btreeHeader.getRootPage().delete( key, value, revision );

        if ( result instanceof NotPresentResult )
        {
            // Key not found.
            return result;
        }

        // Create a new BTreeHeader
        BTreeHeader<K, V> newBtreeHeader = btreeHeader.copy();

        // Inject the old B-tree header into the pages to be freed
        // if we are deleting an element from a management BTree
        if ( ( btreeType == BTreeTypeEnum.BTREE_OF_BTREES ) || ( btreeType == BTreeTypeEnum.COPIED_PAGES_BTREE ) )
        {
            PageIO[] pageIos = recordManager.readPageIOs( btreeHeader.getBTreeHeaderOffset(), -1L );

            for ( PageIO pageIo : pageIos )
            {
                recordManager.freedPages.add( pageIo );
            }
        }

        // The element was found, and removed
        AbstractDeleteResult<K, V> removeResult = ( AbstractDeleteResult<K, V> ) result;

        // This is a new root
        Page<K, V> newRootPage = removeResult.getModifiedPage();

        // Write the modified page on disk
        // Note that we don't use the holder, the new root page will
        // remain in memory.
        writePage( newRootPage, revision );

        // Decrease the number of elements in the current tree
        newBtreeHeader.decrementNbElems();
        newBtreeHeader.setRootPage( newRootPage );
        newBtreeHeader.setRevision( revision );

        // Write down the data on disk
        long newBtreeHeaderOffset = recordManager.writeBtreeHeader( this, newBtreeHeader );

        // Update the B-tree of B-trees with this new offset, if we are not already doing so
        switch ( btreeType )
        {
            case PERSISTED:
                // We have a new B-tree header to inject into the B-tree of btrees
                recordManager.addInBtreeOfBtrees( getName(), revision, newBtreeHeaderOffset );

                recordManager.addInCopiedPagesBtree( getName(), revision, result.getCopiedPages() );

                // Store the new revision
                storeRevision( newBtreeHeader, recordManager.isKeepRevisions() );

                break;

            case PERSISTED_SUB:
                // Sub-B-trees are only updating the CopiedPage B-tree
                recordManager.addInCopiedPagesBtree( getName(), revision, result.getCopiedPages() );

                //btreeRevisions.put( revision, newBtreeHeader );

                currentRevision.set( revision );

                break;

            case BTREE_OF_BTREES:
                // The B-tree of B-trees or the copiedPages B-tree has been updated, update the RMheader parameters
                recordManager.updateRecordManagerHeader( newBtreeHeaderOffset, -1L );

                // We can free the copied pages
                recordManager.freePages( this, revision, result.getCopiedPages() );

                // Store the new revision
                storeRevision( newBtreeHeader, recordManager.isKeepRevisions() );

                break;

            case COPIED_PAGES_BTREE:
                // The B-tree of B-trees or the copiedPages B-tree has been updated, update the RMheader parameters
                recordManager.updateRecordManagerHeader( -1L, newBtreeHeaderOffset );

                // We can free the copied pages
                recordManager.freePages( this, revision, result.getCopiedPages() );

                // Store the new revision
                storeRevision( newBtreeHeader, recordManager.isKeepRevisions() );

                break;

            default:
                // Nothing to do for sub-btrees
                break;
        }

        // Return the value we have found if it was modified
        return result;
    }