fix CSV generation

datastructures-csv/src/main/java/org/xbib/datastructures/csv/Generator.java

@@ -37,19 +37,20 @@ public class Generator implements Constants, Closeable, Flushable {
         return this;
     }
 
-    public void write(String value) throws IOException {
+    public synchronized void write(String value) throws IOException {
+        if (col >= keys.size()) {
+            writer.write(LF);
+            row++;
+            col = 0;
+        } else {
             if (col > 0) {
                 writer.write(COMMA);
             }
+        }
         if (value != null) {
             writer.write(escape(value));
         }
         col++;
-        if (col > keys.size()) {
-            writer.write(LF);
-            row++;
-            col = 0;
-        }
     }
 
     public int getColumn() {

datastructures-csv/src/test/java/org/xbib/datastructures/csv/test/GeneratorTest.java

@@ -10,7 +10,32 @@ import java.util.Arrays;
 public class GeneratorTest {
 
     @Test
-    public void test() throws IOException {
+    public void testOneColumn() throws IOException {
+        StringWriter writer = new StringWriter();
+        Generator gen = new Generator(writer);
+        gen.keys(Arrays.asList("a"));
+        for (int i = 0; i < 2; i++) {
+            gen.write("val" + i);
+        }
+        gen.close();
+        assertEquals("val0\nval1", writer.toString());
+    }
+
+    @Test
+    public void testTwoColumns() throws IOException {
+        StringWriter writer = new StringWriter();
+        Generator gen = new Generator(writer);
+        gen.keys(Arrays.asList("a", "b"));
+        for (int i = 0; i < 2; i++) {
+            gen.write("val" + i);
+            gen.write("val" + i);
+        }
+        gen.close();
+        assertEquals("val0,val0\nval1,val1", writer.toString());
+    }
+
+    @Test
+    public void testThreeColumns() throws IOException {
         StringWriter writer = new StringWriter();
         Generator gen = new Generator(writer);
         gen.keys(Arrays.asList("a", "b", "c"));