<action issue="CSV-120" type="add" dev="ggregory" due-to="Sergei Lebedev">CSVFormat#withHeader doesn't work with CSVPrinter</action>

garydgregory · garydgregory · commit 1282503fb97d · 2014-06-09T22:21:22.000Z
git-svn-id: https://svn.apache.org/repos/asf/commons/proper/csv/trunk@1601517 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/changes/changes.xml b/src/changes/changes.xml
@@ -39,7 +39,8 @@
   </properties>
   <body>
 
-    <release version="1.0" date="TBD" description="First release">
+    <release version="1.0" date="TBD" description="First release">    
+      <action issue="CSV-120" type="add" dev="ggregory" due-to="Sergei Lebedev">CSVFormat#withHeader doesn't work with CSVPrinter</action>
       <action issue="CSV-119" type="add" dev="ggregory" due-to="Sergei Lebedev">CSVFormat is missing a print(...) method</action>
       <action issue="CSV-118" type="fix" dev="ggregory" due-to="Enrique Lara">CSVRecord.toMap() throws NPE on formats with no
         headers.</action>
diff --git a/src/main/java/org/apache/commons/csv/CSVFormat.java b/src/main/java/org/apache/commons/csv/CSVFormat.java
@@ -605,8 +605,10 @@ public CSVParser parse(final Reader in) throws IOException {
      * @param out
      *        the output
      * @return a printer to an output
+     * @throws IOException
+     *         thrown if the optional header cannot be printed.
      */
-    public CSVPrinter print(final Appendable out) {
+    public CSVPrinter print(final Appendable out) throws IOException {
         return new CSVPrinter(out, this);
     }
 
diff --git a/src/main/java/org/apache/commons/csv/CSVPrinter.java b/src/main/java/org/apache/commons/csv/CSVPrinter.java
@@ -45,24 +45,31 @@ public final class CSVPrinter implements Flushable, Closeable {
     /**
      * Creates a printer that will print values to the given stream following the CSVFormat.
      * <p>
-     * Currently, only a pure encapsulation format or a pure escaping format is supported. Hybrid formats
-     * (encapsulation and escaping with a different character) are not supported.
+     * Currently, only a pure encapsulation format or a pure escaping format is supported. Hybrid formats (encapsulation
+     * and escaping with a different character) are not supported.
      * </p>
-     *
+     * 
      * @param out
-     *            stream to which to print. Must not be null.
+     *        stream to which to print. Must not be null.
      * @param format
-     *            the CSV format. Must not be null.
+     *        the CSV format. Must not be null.
+     * @throws IOException
+     *         thrown if the optional header cannot be printed.
      * @throws IllegalArgumentException
-     *             thrown if the parameters of the format are inconsistent or if either out or format are null.
+     *         thrown if the parameters of the format are inconsistent or if either out or format are null.
      */
-    public CSVPrinter(final Appendable out, final CSVFormat format) {
+    public CSVPrinter(final Appendable out, final CSVFormat format) throws IOException {
         Assertions.notNull(out, "out");
         Assertions.notNull(format, "format");
 
         this.out = out;
         this.format = format;
         this.format.validate();
+        // TODO: Is it a good idea to do this here instead of on the first call to a print method?
+        // It seems a pain to have to track whether the header has already been printed or not.
+        if (format.getHeader() != null) {
+            this.printRecord((Object[]) format.getHeader());
+        }
     }
 
     // ======================================================
diff --git a/src/test/java/org/apache/commons/csv/CSVPrinterTest.java b/src/test/java/org/apache/commons/csv/CSVPrinterTest.java
@@ -485,6 +485,17 @@ public void testDelimiterPlain() throws IOException {
         printer.close();
     }
 
+    @Test
+    public void testHeader() throws IOException {
+        final StringWriter sw = new StringWriter();
+        final CSVPrinter printer = new CSVPrinter(sw, CSVFormat.DEFAULT.withQuoteChar(null)
+                .withHeader("C1", "C2", "C3"));
+        printer.printRecord("a", "b", "c");
+        printer.printRecord("x", "y", "z");
+        assertEquals("C1,C2,C3\r\na,b,c\r\nx,y,z\r\n", sw.toString());
+        printer.close();
+    }
+
     @Test
     public void testEOLPlain() throws IOException {
         final StringWriter sw = new StringWriter();
