org.aktin.broker.query.io.MultipartTableWriter Maven / Gradle / Ivy

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package org.aktin.broker.query.io;

import java.io.BufferedWriter;
import java.io.IOException;
import java.nio.charset.Charset;

import org.aktin.broker.query.io.table.TableExport;
import org.aktin.broker.query.io.table.TableWriter;

/**
 * Write text table data into a {@link MultipartOutputStream}.
 *
 * @author R.W.Majeed
 *
 */
public class MultipartTableWriter implements TableExport {
	public static final String MEDIA_TYPE_TAB = "text/tab-separated-values";
	public static final String MEDIA_TYPE_CSV = "text/comma-separated-values";

	private String fieldSeparator;
	private String recordSeparator;
	/** String to write to the file instead of a {@code null} value. Defaults to empty string. */
	private String nullString;
	private Charset charset;
	private MultipartOutputStream output;

	/**
	 * Create an instance by wrapping a {@link MultipartOutputStream}. Important: the underlying
	 * stream is not closed, when the table export is closed.
	 * @param output underlying stream, will not be closed by this class.
	 * @param charset charset to use for producing text files
	 */
	public MultipartTableWriter(MultipartOutputStream output, Charset charset) {
		this.output = output;
		this.charset = charset;
		this.fieldSeparator = "\t";
		this.recordSeparator = "\r\n";
		this.nullString = "";
	}

	private class TableWriterImpl implements TableWriter{
		private BufferedWriter writer;

		public TableWriterImpl(BufferedWriter writer) {
			this.writer = writer;
		}
		private void writeRecord(String[] values) throws IOException{
			for( int i=0; i