/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.wicket.extensions.markup.html.repeater.data.table.export;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.nio.charset.Charset;
import java.util.Iterator;
import java.util.List;
import org.apache.wicket.Application;
import org.apache.wicket.Session;
import org.apache.wicket.markup.repeater.data.IDataProvider;
import org.apache.wicket.model.Model;
import org.apache.wicket.util.convert.IConverter;
import org.apache.wicket.util.lang.Args;
/**
* An {@link IDataExporter} that exports data to a CSV file. This class allows for customization of the exact CSV format, including
* setting the delimiter, the text quoting character and the character set.
* <p>
* This class will export CSV files in a format consistent with RFC4180 by default.
*
* @author Jesse Long
*/
public class CSVDataExporter extends AbstractDataExporter
{
private char delimiter = ',';
private String characterSet = "utf-8";
private char quoteCharacter = '"';
private boolean exportHeadersEnabled = true;
/**
* Creates a new instance.
*/
public CSVDataExporter()
{
super(Model.of("CSV"), "text/csv", "csv");
}
/**
* Sets the delimiter to be used to separate fields. The default delimiter is a colon.
*
* @param delimiter
* The delimiter to be used to separate fields.
* @return {@code this}, for chaining.
*/
public CSVDataExporter setDelimiter(char delimiter)
{
this.delimiter = delimiter;
return this;
}
/**
* Returns the delimiter to be used for separating fields.
*
* @return the delimiter to be used for separating fields.
*/
public char getDelimiter()
{
return delimiter;
}
/**
* Returns the character set encoding to be used when exporting data.
*
* @return the character set encoding to be used when exporting data.
*/
public String getCharacterSet()
{
return characterSet;
}
/**
* Sets the character set encoding to be used when exporting data. This defaults to UTF-8.
*
* @param characterSet
* The character set encoding to be used when exporting data.
* @return {@code this}, for chaining.
*/
public CSVDataExporter setCharacterSet(String characterSet)
{
this.characterSet = Args.notNull(characterSet, "characterSer");
return this;
}
/**
* Returns the character to be used for quoting fields.
*
* @return the character to be used for quoting fields.
*/
public char getQuoteCharacter()
{
return quoteCharacter;
}
/**
* Sets the character to be used to quote fields. This defaults to double quotes,
*
* @param quoteCharacter
* The character to be used to quote fields.
* @return {@code this}, for chaining.
*/
public CSVDataExporter setQuoteCharacter(char quoteCharacter)
{
this.quoteCharacter = quoteCharacter;
return this;
}
/**
* Returns the content type of the exported data. For CSV, this is normally
* "text/csv". This methods adds the character set and header values, in accordance with
* RFC4180.
*
* @return the content type of the exported data.
*/
@Override
public String getContentType()
{
return super.getContentType() + "; charset=" + characterSet + "; header=" + ((exportHeadersEnabled) ? "present" : "absent");
}
/**
* Turns on or off export headers functionality. If this is set to {@code true}, then the first
* line of the export will contain the column headers. This defaults to {@code true}.
*
* @param exportHeadersEnabled
* A boolean indicating whether or not headers should be exported.
* @return {@code this}, for chaining.
*/
public CSVDataExporter setExportHeadersEnabled(boolean exportHeadersEnabled)
{
this.exportHeadersEnabled = exportHeadersEnabled;
return this;
}
/**
* Indicates if header exporting is enabled. Defaults to {@code true}.
*
* @return a boolean indicating if header exporting is enabled.
*/
public boolean isExportHeadersEnabled()
{
return exportHeadersEnabled;
}
/**
* Quotes a value for export to CSV. According to RFC4180, this should just duplicate all occurrences
* of the quote character and wrap the result in the quote character.
*
* @param value
* The value to be quoted.
* @return a quoted copy of the value.
*/
protected String quoteValue(String value)
{
return quoteCharacter + value.replace("" + quoteCharacter, "" + quoteCharacter + quoteCharacter) + quoteCharacter;
}
@Override
public <T> void exportData(IDataProvider<T> dataProvider, List<IExportableColumn<T, ?>> columns, OutputStream outputStream)
throws IOException
{
PrintWriter out = new PrintWriter(new OutputStreamWriter(outputStream, Charset.forName(characterSet)));
try
{
if (isExportHeadersEnabled())
{
boolean first = true;
for (IExportableColumn<T, ?> col : columns)
{
if (first)
{
first = false;
}
else
{
out.print(delimiter);
}
out.print(quoteValue(col.getDisplayModel().getObject()));
}
out.print("\r\n");
}
long numberOfRows = dataProvider.size();
Iterator<? extends T> rowIterator = dataProvider.iterator(0, numberOfRows);
while (rowIterator.hasNext())
{
T row = rowIterator.next();
boolean first = true;
for (IExportableColumn<T, ?> col : columns)
{
if (first)
{
first = false;
}
else
{
out.print(delimiter);
}
Object o = col.getDataModel(dataProvider.model(row)).getObject();
if (o != null)
{
Class<?> c = o.getClass();
String s;
IConverter converter = Application.get().getConverterLocator().getConverter(c);
if (converter == null)
{
s = o.toString();
}
else
{
s = converter.convertToString(o, Session.get().getLocale());
}
out.print(quoteValue(s));
}
}
out.print("\r\n");
}
}
finally
{
out.close();
}
}
}