org.apache.poi.xssf.model

Class SharedStringsTable

java.lang.Object

org.apache.poi.ooxml.POIXMLDocumentPart

org.apache.poi.xssf.model.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).

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.poi.ooxml.POIXMLDocumentPart

POIXMLDocumentPart.RelationPart

Field Summary

Fields

Modifier and Type	Field and Description
protected int	count An integer representing the total count of strings in the workbook.
protected int	uniqueCount An integer representing the total count of unique strings in the Shared String Table.

Constructor Summary

Constructors

Constructor and Description
SharedStringsTable()
SharedStringsTable(PackagePart part)

Method Summary

Modifier and Type	Method and Description
int	addSharedStringItem(RichTextString string) Add an entry to this Shared String table (a new value is appended to the end).
void	close() Close any open resources, like temp files.
protected void	commit() Save the content in the underlying package part.
int	getCount() Return an integer representing the total count of strings in the workbook.
RichTextString	getItemAt(int idx) Return a string item by index
java.util.List<RichTextString>	getSharedStringItems() Provide access to the strings in the SharedStringsTable
int	getUniqueCount() Returns an integer representing the total count of unique strings in the Shared String Table.
void	readFrom(java.io.InputStream is) Read this shared strings table from an XML file.
void	writeTo(java.io.OutputStream out) Write this table out as XML.
protected java.lang.String	xmlText(org.openxmlformats.schemas.spreadsheetml.x2006.main.CTRst st)

Methods inherited from class org.apache.poi.ooxml.POIXMLDocumentPart

_invokeOnDocumentRead, addRelation, createRelationship, createRelationship, createRelationship, getNextPartNumber, getPackagePart, getParent, getRelationById, getRelationId, getRelationPartById, getRelationParts, getRelations, getTargetPart, isCommitted, onDocumentCreate, onDocumentRead, onDocumentRemove, onSave, prepareForCommit, read, rebase, removeRelation, removeRelation, removeRelation, setCommitted, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

count

protected int count

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.

uniqueCount

protected int uniqueCount

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.

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.

xmlText

protected java.lang.String xmlText(org.openxmlformats.schemas.spreadsheetml.x2006.main.CTRst st)

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.

commit

protected void commit()
               throws java.io.IOException

Description copied from class: POIXMLDocumentPart

Save the content in the underlying package part. Default implementation is empty meaning that the package part is left unmodified.

Sub-classes should override and add logic to marshal the "model" into Ooxml4J.

For example, the code saving a generic XML entry may look as follows:

 protected void commit() throws IOException {
   PackagePart part = getPackagePart();
   try (OutputStream out = part.getOutputStream()) {
     XmlObject bean = getXmlBean(); //the "model" which holds changes in memory
     bean.save(out, DEFAULT_XML_OPTIONS);
   }
 }
 

Overrides:

commit in class POIXMLDocumentPart

Throws:

java.io.IOException - a subclass may throw an IOException if the changes can't be committed

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.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Throws:

java.io.IOException - if an error occurs while closing.

Since:

4.0.0