private InsertResult addAndSplit()

in mavibot/src/main/java/org/apache/directory/mavibot/btree/PersistedNode.java [982:1080]
61 lines of code
5 McCabe index (conditional complexity)

    private InsertResult<K, V> addAndSplit( List<Page<K, V>> copiedPages, long revision, K pivot, Page<K, V> leftPage,
        Page<K, V> rightPage, int pos ) throws IOException
    {
        int middle = btree.getPageSize() >> 1;

        // Create two new pages
        PersistedNode<K, V> newLeftPage = new PersistedNode<K, V>( btree, revision, middle );
        PersistedNode<K, V> newRightPage = new PersistedNode<K, V>( btree, revision, middle );

        // Determinate where to store the new value
        // If it's before the middle, insert the value on the left,
        // the key in the middle will become the new pivot
        if ( pos < middle )
        {
            // Copy the keys and the children up to the insertion position
            System.arraycopy( keys, 0, newLeftPage.keys, 0, pos );
            System.arraycopy( children, 0, newLeftPage.children, 0, pos );

            // Add the new element
            newLeftPage.keys[pos] = new PersistedKeyHolder<K>( btree.getKeySerializer(), pivot );
            newLeftPage.children[pos] = createHolder( leftPage );
            newLeftPage.children[pos + 1] = createHolder( rightPage );

            // And copy the remaining elements minus the new pivot
            System.arraycopy( keys, pos, newLeftPage.keys, pos + 1, middle - pos - 1 );
            System.arraycopy( children, pos + 1, newLeftPage.children, pos + 2, middle - pos - 1 );

            // Copy the keys and the children in the right page
            System.arraycopy( keys, middle, newRightPage.keys, 0, middle );
            System.arraycopy( children, middle, newRightPage.children, 0, middle + 1 );

            // Create the result
            pivot = keys[middle - 1].getKey();

            if ( pivot == null )
            {
                pivot = keys[middle - 1].getKey();
            }

            InsertResult<K, V> result = new SplitResult<K, V>( copiedPages, pivot, newLeftPage,
                newRightPage );
            result.addCopiedPage( this );

            return result;
        }
        else if ( pos == middle )
        {
            // A special case : the pivot will be propagated up in the tree
            // The left and right pages will be spread on the two new pages
            // Copy the keys and the children up to the insertion position (here, middle)
            System.arraycopy( keys, 0, newLeftPage.keys, 0, middle );
            System.arraycopy( children, 0, newLeftPage.children, 0, middle );
            newLeftPage.children[middle] = createHolder( leftPage );

            // And process the right page now
            System.arraycopy( keys, middle, newRightPage.keys, 0, middle );
            System.arraycopy( children, middle + 1, newRightPage.children, 1, middle );
            newRightPage.children[0] = createHolder( rightPage );

            // Create the result
            InsertResult<K, V> result = new SplitResult<K, V>( copiedPages, pivot, newLeftPage, newRightPage );
            result.addCopiedPage( this );

            return result;
        }
        else
        {
            // Copy the keys and the children up to the middle
            System.arraycopy( keys, 0, newLeftPage.keys, 0, middle );
            System.arraycopy( children, 0, newLeftPage.children, 0, middle + 1 );

            // Copy the keys and the children in the right page up to the pos
            System.arraycopy( keys, middle + 1, newRightPage.keys, 0, pos - middle - 1 );
            System.arraycopy( children, middle + 1, newRightPage.children, 0, pos - middle - 1 );

            // Add the new element
            newRightPage.keys[pos - middle - 1] = new PersistedKeyHolder<K>( btree.getKeySerializer(), pivot );
            newRightPage.children[pos - middle - 1] = createHolder( leftPage );
            newRightPage.children[pos - middle] = createHolder( rightPage );

            // And copy the remaining elements minus the new pivot
            System.arraycopy( keys, pos, newRightPage.keys, pos - middle, nbElems - pos );
            System.arraycopy( children, pos + 1, newRightPage.children, pos + 1 - middle, nbElems - pos );

            // Create the result
            pivot = keys[middle].getKey();

            if ( pivot == null )
            {
                pivot = keys[middle].getKey();
            }

            InsertResult<K, V> result = new SplitResult<K, V>( copiedPages, pivot, newLeftPage,
                newRightPage );
            result.addCopiedPage( this );

            return result;
        }
    }