[TAP] Add HTML as output format.

src/tap/formatter/HTMLFormat.java

+package tap.formatter;
+
+/*
+ * This file is part of TAPLibrary.
+ * 
+ * TAPLibrary is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * TAPLibrary is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with TAPLibrary.  If not, see <http://www.gnu.org/licenses/>.
+ * 
+ * Copyright 2014 - Astronomisches Rechen Institut (ARI)
+ */
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintWriter;
+
+import tap.ServiceConnection;
+import tap.TAPException;
+import tap.TAPExecutionReport;
+import tap.data.TableIterator;
+import uk.ac.starlink.votable.VOSerializer;
+import uws.ISO8601Format;
+import uws.service.log.UWSLog.LogLevel;
+import adql.db.DBColumn;
+
+/**
+ * Format any given query (table) result into HTML.
+ * 
+ * @author Gr&eacute;gory Mantelet (ARI)
+ * @version 2.0 (10/2014)
+ * @since 2.0
+ */
+public class HTMLFormat implements OutputFormat {
+
+	/** Indicates whether a format report (start and end date/time) must be printed in the log output.  */
+	private boolean logFormatReport;
+
+	/** The {@link ServiceConnection} to use (for the log and to have some information about the service (particularly: name, description). */
+	protected final ServiceConnection service;
+
+	/**
+	 * Creates an HTML formatter.
+	 * 
+	 * @param service	Description of the TAP service.
+	 * 
+	 * @throws NullPointerException	If the given service connection is <code>null</code>.
+	 */
+	public HTMLFormat(final ServiceConnection service) throws NullPointerException{
+		this(service, true);
+	}
+
+	/**
+	 * Creates an HTML formatter
+	 * 
+	 * @param service			Description of the TAP service.
+	 * @param logFormatReport	<i>true</i> to write a log entry (with nb rows and columns + writing duration) each time a result is written, <i>false</i> otherwise.
+	 * 
+	 * @throws NullPointerException	If the given service connection is <code>null</code>.
+	 */
+	public HTMLFormat(final ServiceConnection service, final boolean logFormatReport) throws NullPointerException{
+		if (service == null)
+			throw new NullPointerException("The given service connection is NULL!");
+
+		this.service = service;
+		this.logFormatReport = logFormatReport;
+	}
+
+	@Override
+	public String getMimeType(){
+		return "text/html";
+	}
+
+	@Override
+	public String getShortMimeType(){
+		return "html";
+	}
+
+	@Override
+	public String getDescription(){
+		return null;
+	}
+
+	@Override
+	public String getFileExtension(){
+		return ".html";
+	}
+
+	@Override
+	public void writeResult(TableIterator result, OutputStream output, TAPExecutionReport execReport, Thread thread) throws TAPException, InterruptedException{
+		try{
+			final long startTime = System.currentTimeMillis();
+
+			// Prepare the output stream:
+			final PrintWriter writer = new PrintWriter(output);
+			writer.println("<table>");
+
+			// Write header:
+			DBColumn[] columns = writeHeader(result, writer, execReport, thread);
+
+			// Write data:
+			int nbRows = writeData(result, columns, writer, execReport, thread);
+
+			writer.println("</table>");
+			writer.flush();
+
+			// Report stats about the result writing:
+			if (logFormatReport)
+				service.getLogger().logTAP(LogLevel.INFO, execReport, "FORMAT", "Result formatted (in HTML ; " + nbRows + " rows ; " + columns.length + " columns) in " + (System.currentTimeMillis() - startTime) + "ms!", null);
+
+		}catch(Exception ex){
+			service.getLogger().logTAP(LogLevel.ERROR, execReport, "FORMAT", "Error while formatting in HTML!", ex);
+		}
+	}
+
+	/**
+	 * Write the whole header (one row whose columns are just the columns' name).
+	 * 
+	 * @param result		Result to write later (but it contains also metadata that was extracted from the result itself).
+	 * @param writer		Output in which the metadata must be written.
+	 * @param execReport	Execution report (which contains the metadata extracted/guessed from the ADQL query).
+	 * @param thread		Thread which has asked for this formatting (it must be used in order to test the {@link Thread#isInterrupted()} flag and so interrupt everything if need).
+	 * 
+	 * @return	All the written metadata.
+	 * 
+	 * @throws IOException				If there is an error while writing something in the output.
+	 * @throws InterruptedException		If the thread has been interrupted.
+	 * @throws TAPException				If any other error occurs.
+	 */
+	protected DBColumn[] writeHeader(TableIterator result, PrintWriter writer, TAPExecutionReport execReport, Thread thread) throws IOException, TAPException, InterruptedException{
+		// Prepend a description of this result:
+		writer.print("<caption>TAP result");
+		if (service.getProviderName() != null)
+			writer.print(" from " + VOSerializer.formatText(service.getProviderName()));
+		writer.print(" on " + ISO8601Format.format(System.currentTimeMillis()));
+		writer.print("<br/><em>" + VOSerializer.formatText(execReport.parameters.getQuery()) + "</em>");
+		writer.println("</caption>");
+
+		// Get the columns meta:
+		DBColumn[] selectedColumns = execReport.resultingColumns;
+
+		// If meta are not known, no header will be written:
+		int nbColumns = (selectedColumns == null) ? -1 : selectedColumns.length;
+		if (nbColumns > 0){
+			writer.println("<thead>");
+			writer.print("<tr>");
+
+			// Write all columns' name:
+			for(int i = 0; i < nbColumns; i++){
+				writer.print("<th>");
+				writer.print(VOSerializer.formatText(selectedColumns[i].getADQLName()));
+				writer.print("</th>");
+			}
+
+			// Go to a new line (in order to prepare the data writing):
+			writer.println("</tr>");
+			writer.println("</thead>");
+			writer.flush();
+		}
+
+		// Returns the written columns:
+		return selectedColumns;
+	}
+
+	/**
+	 * Write all the data rows.
+	 * 
+	 * @param result			Result to write.	
+	 * @param selectedColumns	All columns' metadata.
+	 * @param writer			Print writer in which the data must be written.
+	 * @param execReport		Execution report (which contains the maximum allowed number of records to output).
+	 * @param thread			Thread which has asked for this formatting (it must be used in order to test the {@link Thread#isInterrupted()} flag and so interrupt everything if need).
+	 * 
+	 * @return	The number of written result rows. (<i>note: if this number is greater than the value of MAXREC: OVERFLOW</i>)
+	 * 
+	 * @throws IOException				If there is an error while writing something in the output stream.
+	 * @throws InterruptedException		If the thread has been interrupted.
+	 * @throws TAPException				If any other error occurs.
+	 */
+	protected int writeData(TableIterator result, DBColumn[] selectedColumns, PrintWriter writer, TAPExecutionReport execReport, Thread thread) throws IOException, TAPException, InterruptedException{
+		int nbRows = 0;
+
+		writer.println("<tbody>");
+
+		while(result.nextRow()){
+			// Deal with OVERFLOW, if needed:
+			if (execReport.parameters.getMaxRec() > 0 && nbRows >= execReport.parameters.getMaxRec()){ // that's to say: OVERFLOW !
+				writer.println("<tr class=\"OVERFLOW\"><td colspan=\"" + selectedColumns.length + "\"><em><strong>OVERFLOW</strong> (more rows were available but have been truncated by the TAP service)</em></td></tr>");
+				break;
+			}
+
+			writer.print("<tr>");
+
+			while(result.hasNextCol()){
+				writer.print("<td>");
+
+				// Write the column value:
+				Object colVal = result.nextCol();
+				if (colVal != null)
+					writer.print(VOSerializer.formatText(colVal.toString()));
+
+				writer.print("</td>");
+
+				if (thread.isInterrupted())
+					throw new InterruptedException();
+			}
+			writer.println("</tr>");
+			nbRows++;
+
+			if (thread.isInterrupted())
+				throw new InterruptedException();
+		}
+
+		writer.println("</tbody>");
+		writer.flush();
+
+		return nbRows;
+	}
+
+}