Class Paging


  • public class Paging
    extends Object
    Paging. A utility for maintaining paged indexes for a collection of N items. There are two types of cursor: a) Paged This type of cursor is driven from a page number and page size. Random access within the collection is possible by jumping straight to a page. A simple scroll through the collection is supported by iterating through each next page. b) Windowed This type of cursor is driven from a skip row count and maximum number of rows. Random access is not supported. The collection of items is simply scrolled through from start to end by iterating through each next set of rows. In either case, a paging cursor provides a start row and end row which may be used to extract the items for the page from the collection of N items. A zero (or less) page size or row maximum means "unlimited". Zero or one based Page and Rows indexes are supported. By default, Pages are 1 based and Rows are 0 based. At any time, -1 is returned to represent "out of range" i.e. for next, previous, last page. Pseudo-code for traversing through a collection of N items (10 at a time): Paging paging = new Paging(); Cursor page = paging.createCursor(N, paging.createPage(1, 10)); while (page.isInRange()) { for (long i = page.getStartRow(); i <= page.getEndRow(); i++) { ...collection[i]... } page = paging.createCursor(N, paging.createPage(page.getNextPage(), page.getPageSize()); } Cursor window = paging.createCursor(N, paging.createWindow(0, 10)); while (window.isInRange()) { for (long i = window.getStartRow(); i <= window.getEndRow(); i++) { ...collection[i]... } window = paging.createCursor(N, paging.createWindow(window.getNextPage(), window.getPageSize()); }
    Author:
    davidc
    • Constructor Detail

      • Paging

        public Paging()
    • Method Detail

      • setZeroBasedPage

        public void setZeroBasedPage​(boolean zeroBasedPage)
        Sets zero based page index Note: scoped to this paging cursor instance
        Parameters:
        zeroBasedPage - true => 0 based, false => 1 based
      • isZeroBasedPage

        public boolean isZeroBasedPage()
        Is zero based page index? Note: scoped to this paging cursor instance
        Returns:
        true => 0 based, false => 1 based
      • setZeroBasedRow

        public void setZeroBasedRow​(boolean zeroBasedRow)
        Sets zero based row index Note: scoped to this paging cursor instance
        Parameters:
        zeroBasedRow - true => 0 based, false => 1 based
      • isZeroBasedRow

        public boolean isZeroBasedRow()
        Is zero based row index? Note: scoped to this paging cursor instance
        Returns:
        true => 0 based, false => 1 based
      • createPageOrWindow

        public Page createPageOrWindow​(Map<String,​String> args)
        Create a Page or Window from standardised request arguments For Paged based index (take precedence over window based index, if both are specified): - request args pageNo => page number index pageSize => size of page For Window based index (as defined by CMIS): - request args (take precedence over header values if both are specified) skipCount => row number start index maxItems => size of page
        Parameters:
        args - request args
        Returns:
        page (if pageNumber driven) or window (if skipCount driven)
      • createPageOrWindow

        public Page createPageOrWindow​(Integer pageNumber,
                                       Integer pageSize,
                                       Integer skipCount,
                                       Integer maxItems)
        Create a Page or Window
        Parameters:
        pageNumber - page number (optional and paired with pageSize)
        pageSize - page size (optional and paired with pageNumber)
        skipCount - skipCount (optional and paired with maxItems)
        maxItems - maxItems (optional and paired with skipCount)
        Returns:
        page (if pageNumber driven) or window (if skipCount driven)
      • createPage

        public Page createPage​(int pageNumber,
                               int pageSize)
        Create a Page
        Parameters:
        pageNumber - page number
        pageSize - page size
        Returns:
        the page
      • createUnlimitedPage

        public Page createUnlimitedPage()
        Create an unlimited Page
        Returns:
        page (single Page starting at first page of unlimited page size)
      • createWindow

        public Page createWindow​(int skipRows,
                                 int maxRows)
        Create a Window
        Parameters:
        skipRows - number of rows to skip
        maxRows - maximum number of rows in window
        Returns:
        the window
      • createCursor

        public Cursor createCursor​(int totalRows,
                                   Page page)
        Create a Cursor
        Parameters:
        totalRows - total number of rows in cursor (< 0 for don't know)
        page - the page / window within cursor
        Returns:
        the cursor
      • createPagedResults

        public PagedResults createPagedResults​(Object[] results,
                                               Cursor cursor)
        Create a Paged Result Set
        Parameters:
        results - the results for the page within the cursor
        cursor - the cursor
        Returns:
        the paged result set
      • createPagedResult

        public PagedResults createPagedResult​(Object result,
                                              Cursor cursor)
        Create a Paged Result Set
        Parameters:
        result - the results for the page within the cursor
        cursor - the cursor
        Returns:
        the paged result set