org.apache.poi.xssf.model.SharedStringsTable Maven / Gradle / Ivy
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package org.apache.poi.xssf.model;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.poi.POIXMLDocumentPart;
import org.apache.poi.openxml4j.opc.PackagePart;
import org.apache.poi.openxml4j.opc.PackageRelationship;
import org.apache.xmlbeans.XmlException;
import org.apache.xmlbeans.XmlOptions;
import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTRst;
import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTSst;
import org.openxmlformats.schemas.spreadsheetml.x2006.main.SstDocument;
/**
* 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).
*
*
* @author Nick Birch
* @author Yegor Kozlov
*/
public class SharedStringsTable extends POIXMLDocumentPart {
/**
* Array of individual string items in the Shared String table.
*/
private final List strings = new ArrayList();
/**
* Maps strings and their indexes in the strings arrays
*/
private final Map stmap = new HashMap();
/**
* 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.
*/
private int count;
/**
* 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.
*/
private int uniqueCount;
private SstDocument _sstDoc;
private final static XmlOptions options = new XmlOptions();
static {
options.put( XmlOptions.SAVE_INNER );
options.put( XmlOptions.SAVE_AGGRESSIVE_NAMESPACES );
options.put( XmlOptions.SAVE_USE_DEFAULT_NAMESPACE );
options.setSaveImplicitNamespaces(Collections.singletonMap("", "http://schemas.openxmlformats.org/spreadsheetml/2006/main"));
}
public SharedStringsTable() {
super();
_sstDoc = SstDocument.Factory.newInstance();
_sstDoc.addNewSst();
}
public SharedStringsTable(PackagePart part, PackageRelationship rel) throws IOException {
super(part, rel);
readFrom(part.getInputStream());
}
/**
* Read this shared strings table from an XML file.
*
* @param is The input stream containing the XML document.
* @throws IOException if an error occurs while reading.
*/
@SuppressWarnings("deprecation") //YK: getXYZArray() array accessors are deprecated in xmlbeans with JDK 1.5 support
public void readFrom(InputStream is) throws IOException {
try {
int cnt = 0;
_sstDoc = SstDocument.Factory.parse(is);
CTSst sst = _sstDoc.getSst();
count = (int)sst.getCount();
uniqueCount = (int)sst.getUniqueCount();
for (CTRst st : sst.getSiArray()) {
stmap.put(getKey(st), cnt);
strings.add(st);
cnt++;
}
} catch (XmlException e) {
throw new IOException(e.getLocalizedMessage());
}
}
private String getKey(CTRst st) {
return st.xmlText(options);
}
/**
* Return a string item by index
*
* @param idx index of item to return.
* @return the item at the specified position in this Shared String table.
*/
public CTRst getEntryAt(int idx) {
return strings.get(idx);
}
/**
* 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.
*
* @return the total count of strings in the workbook
*/
public int getCount(){
return count;
}
/**
* 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.
*
* @return the total count of unique strings in the workbook
*/
public int getUniqueCount(){
return uniqueCount;
}
/**
* Add an entry to this Shared String table (a new value is appened to the end).
*
*
* If the Shared String table already contains this CTRst bean, its index is returned.
* Otherwise a new entry is aded.
*
*
* @param st the entry to add
* @return index the index of added entry
*/
public int addEntry(CTRst st) {
String s = getKey(st);
count++;
if (stmap.containsKey(s)) {
return stmap.get(s);
}
uniqueCount++;
//create a CTRst bean attached to this SstDocument and copy the argument CTRst into it
CTRst newSt = _sstDoc.getSst().addNewSi();
newSt.set(st);
int idx = strings.size();
stmap.put(s, idx);
strings.add(newSt);
return idx;
}
/**
* Provide low-level access to the underlying array of CTRst beans
*
* @return array of CTRst beans
*/
public List getItems() {
return strings;
}
/**
* Write this table out as XML.
*
* @param out The stream to write to.
* @throws IOException if an error occurs while writing.
*/
public void writeTo(OutputStream out) throws IOException {
XmlOptions options = new XmlOptions(DEFAULT_XML_OPTIONS);
// the following two lines turn off writing CDATA
// see Bugzilla 48936
options.setSaveCDataLengthThreshold(1000000);
options.setSaveCDataEntityCountThreshold(-1);
//re-create the sst table every time saving a workbook
CTSst sst = _sstDoc.getSst();
sst.setCount(count);
sst.setUniqueCount(uniqueCount);
_sstDoc.save(out, options);
}
@Override
protected void commit() throws IOException {
PackagePart part = getPackagePart();
OutputStream out = part.getOutputStream();
writeTo(out);
out.close();
}
}