package org.grouplens.lenskit.util.tablewriter;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class MultiplexedTableWriter implements TableWriter {

	private TableLayout layout;
	private List<TableWriter> writers;
	
	public MultiplexedTableWriter(TableLayout layout, List<TableWriter> writers) {
		this.layout = layout;
		this.writers = writers;
	}
	
	public MultiplexedTableWriter(TableLayout layout, TableWriter... writers) {
		this(layout, Arrays.asList(writers));
	}
		
	@Override
	public TableLayout getLayout() {
		return layout;
	}

	@Override
	public void writeRow(Object[] row) throws IOException {
		for (TableWriter w: writers) {
			w.writeRow(row);
		}

	}

	@Override
	public void close() throws IOException {
		ArrayList<IOException> closeExceptions = new ArrayList<IOException>(writers.size());
		for (TableWriter w : writers) {
			try {
				w.close();
			} catch (IOException e) {
				closeExceptions.add(e);
			}
		}
		if (!closeExceptions.isEmpty()) {
			throw closeExceptions.get(0);
		}
	}
}
package org.grouplens.lenskit.util.tablewriter;

import java.io.IOException;
import java.util.Arrays;
import java.util.List;

import org.grouplens.lenskit.eval.util.table.TableImpl;

public class MultiplexedTableWriter implements TableWriter {

	private TableLayout layout;
	private List<TableWriter> writers;
	
	public MultiplexedTableWriter(TableLayout layout, List<TableWriter> writers) {
		this.layout = layout;
		this.writers = writers;
	}
	
	public MultiplexedTableWriter(TableLayout layout, TableWriter... writers) {
		this(layout, Arrays.asList(writers));
	}
		
	@Override
	public TableLayout getLayout() {
		return layout;
	}

	@Override
	public void writeRow(Object[] row) throws IOException {
		for (TableWriter w: writers) {
			w.writeRow(row);
		}

	}

	@Override
	public void close() throws IOException {
		for (TableWriter w : writers) {
			w.close();
		}
	}
}
--- 
+++ 
@@ -1,10 +1,9 @@
 package org.grouplens.lenskit.util.tablewriter;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
-
-import org.grouplens.lenskit.eval.util.table.TableImpl;
 
 public class MultiplexedTableWriter implements TableWriter {
 
@@ -35,8 +34,16 @@
 
 	@Override
 	public void close() throws IOException {
+		ArrayList<IOException> closeExceptions = new ArrayList<IOException>(writers.size());
 		for (TableWriter w : writers) {
-			w.close();
+			try {
+				w.close();
+			} catch (IOException e) {
+				closeExceptions.add(e);
+			}
+		}
+		if (!closeExceptions.isEmpty()) {
+			throw closeExceptions.get(0);
 		}
 	}
 }
Fix closing of multiplexed table writer to close all constituent table writers in presence of exceptions
