Class SharedStringsTable

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable, SharedStrings

    public class SharedStringsTable
    extends POIXMLDocumentPart
    implements SharedStrings, java.io.Closeable
    Table of strings shared across all sheets in a workbook.

    A workbook may contain thousands of cells containing string (non-numeric) data. Furthermore this data is very likely to be repeated across many rows or columns. The goal of implementing a single string table that is shared across the workbook is to improve performance in opening and saving the file by only reading and writing the repetitive information once.

    Consider for example a workbook summarizing information for cities within various countries. There may be a column for the name of the country, a column for the name of each city in that country, and a column containing the data for each city. In this case the country name is repetitive, being duplicated in many cells. In many cases the repetition is extensive, and a tremendous savings is realized by making use of a shared string table when saving the workbook. When displaying text in the spreadsheet, the cell table will just contain an index into the string table as the value of a cell, instead of the full string.

    The shared string table contains all the necessary information for displaying the string: the text, formatting properties, and phonetic properties (for East Asian languages).

    • Constructor Detail

      • SharedStringsTable

        public SharedStringsTable()
      • SharedStringsTable

        public SharedStringsTable​(PackagePart part)
                           throws java.io.IOException
        Throws:
        java.io.IOException
        Since:
        POI 3.14-Beta1
    • Method Detail

      • readFrom

        public void readFrom​(java.io.InputStream is)
                      throws java.io.IOException
        Read this shared strings table from an XML file.
        Parameters:
        is - The input stream containing the XML document.
        Throws:
        java.io.IOException - if an error occurs while reading.
      • getItemAt

        public RichTextString getItemAt​(int idx)
        Return a string item by index
        Specified by:
        getItemAt in interface SharedStrings
        Parameters:
        idx - index of item to return.
        Returns:
        the item at the specified position in this Shared String table.
      • getCount

        public int getCount()
        Return an integer representing the total count of strings in the workbook. This count does not include any numbers, it counts only the total of text strings in the workbook.
        Specified by:
        getCount in interface SharedStrings
        Returns:
        the total count of strings in the workbook
      • getUniqueCount

        public int getUniqueCount()
        Returns an integer representing the total count of unique strings in the Shared String Table. A string is unique even if it is a copy of another string, but has different formatting applied at the character level.
        Specified by:
        getUniqueCount in interface SharedStrings
        Returns:
        the total count of unique strings in the workbook
      • addSharedStringItem

        public int addSharedStringItem​(RichTextString string)
        Add an entry to this Shared String table (a new value is appended to the end).

        If the Shared String table already contains this string entry, its index is returned. Otherwise a new entry is added.

        Parameters:
        string - the entry to add
        Returns:
        index the index of added entry
        Since:
        POI 4.0.0
      • getSharedStringItems

        public java.util.List<RichTextString> getSharedStringItems()
        Provide access to the strings in the SharedStringsTable
        Returns:
        list of shared string instances
      • writeTo

        public void writeTo​(java.io.OutputStream out)
                     throws java.io.IOException
        Write this table out as XML.
        Parameters:
        out - The stream to write to.
        Throws:
        java.io.IOException - if an error occurs while writing.
      • close

        public void close()
                   throws java.io.IOException
        Close any open resources, like temp files. This method is called by XSSFWorkbook#close().

        This implementation is empty but subclasses may need to implement some logic.

        Specified by:
        close in interface java.lang.AutoCloseable
        Specified by:
        close in interface java.io.Closeable
        Throws:
        java.io.IOException - if an error occurs while closing.
        Since:
        4.0.0