Package org.apache.poi.xssf.model

Class SharedStringsTable

java.lang.Object
org.apache.poi.ooxml.POIXMLDocumentPart
org.apache.poi.xssf.model.SharedStringsTable
All Implemented Interfaces:
Closeable, AutoCloseable, SharedStrings
public class SharedStringsTable extends POIXMLDocumentPart implements SharedStrings, 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 Details

    • SharedStringsTable

      public SharedStringsTable()

    • SharedStringsTable

      public SharedStringsTable(PackagePart part) throws IOException
      Throws:
      IOException
      Since:
      POI 3.14-Beta1

  • Method Details

    • readFrom

      public void readFrom(InputStream is) throws IOException
      Read this shared strings table from an XML file.
      Parameters:
      is - The input stream containing the XML document.
      Throws:
      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 List<RichTextString> getSharedStringItems()
      Provide access to the strings in the SharedStringsTable
      Returns:
      list of shared string instances

    • writeTo

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

    • close

      public void close() throws 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 AutoCloseable
      Specified by:
      close in interface Closeable
      Throws:
      IOException - if an error occurs while closing.
      Since:
      4.0.0