Fixes issue 725 (#767)

Adds an option to CsvWriteOptions to specify that all fields should be quoted. The result is that all output is quoted, including column headers and any column data regardless of column type.

The implementation simply passes the arguments to the equivalent Univocity code, which does the rest.

core/src/main/java/tech/tablesaw/io/csv/CsvWriteOptions.java

@@ -17,6 +17,7 @@ public class CsvWriteOptions extends WriteOptions {
   private final char quoteChar;
   private final char escapeChar;
   private final String lineEnd;
+  private final boolean quoteAllFields;
 
   private CsvWriteOptions(Builder builder) {
     super(builder);
@@ -27,6 +28,7 @@ private CsvWriteOptions(Builder builder) {
     this.lineEnd = builder.lineEnd;
     this.ignoreLeadingWhitespaces = builder.ignoreLeadingWhitespaces;
     this.ignoreTrailingWhitespaces = builder.ignoreTrailingWhitespaces;
+    this.quoteAllFields = builder.quoteAllFields;
   }
 
   public boolean header() {
@@ -49,6 +51,10 @@ public char escapeChar() {
     return escapeChar;
   }
 
+  public boolean quoteAllFields() {
+    return quoteAllFields;
+  }
+
   public char quoteChar() {
     return quoteChar;
   }
@@ -82,6 +88,7 @@ public static class Builder extends WriteOptions.Builder {
     private boolean header = true;
     private boolean ignoreLeadingWhitespaces = true;
     private boolean ignoreTrailingWhitespaces = true;
+    private boolean quoteAllFields = false;
     private char separator = ',';
     private String lineEnd = System.lineSeparator();
     private char escapeChar = '\\';
@@ -117,6 +124,18 @@ public CsvWriteOptions.Builder quoteChar(char quoteChar) {
       return this;
     }
 
+    /**
+     * Causes all data exported as a CSV file to be enclosed in quotes. Note that this includes the
+     * headers, and all columns regardless of type
+     *
+     * @param quoteAll {@code} true, to cause all data and column headers to be quoted.
+     * @return this CsvWriteOptionsBuilder
+     */
+    public CsvWriteOptions.Builder quoteAllFields(boolean quoteAll) {
+      this.quoteAllFields = quoteAll;
+      return this;
+    }
+
     public CsvWriteOptions.Builder escapeChar(char escapeChar) {
       this.escapeChar = escapeChar;
       return this;

core/src/main/java/tech/tablesaw/io/csv/CsvWriter.java

@@ -81,6 +81,7 @@ protected static CsvWriterSettings createSettings(CsvWriteOptions options) {
     settings.setIgnoreTrailingWhitespaces(options.ignoreTrailingWhitespaces());
     // writes empty lines as well.
     settings.setSkipEmptyLines(false);
+    settings.setQuoteAllFields(options.quoteAllFields());
     return settings;
   }
 

core/src/test/java/tech/tablesaw/io/csv/CsvWriteOptionsTest.java

@@ -19,6 +19,7 @@ public void testSettingsPropagation() {
             .lineEnd("\r\n")
             .quoteChar('"')
             .separator('.')
+            .quoteAllFields(true)
             .ignoreLeadingWhitespaces(true)
             .ignoreTrailingWhitespaces(true)
             .build();
@@ -28,9 +29,10 @@ public void testSettingsPropagation() {
     assertEquals('.', options.separator());
     assertTrue(options.ignoreLeadingWhitespaces());
     assertTrue(options.ignoreTrailingWhitespaces());
+    assertTrue(options.quoteAllFields());
 
     CsvWriterSettings settings = CsvWriter.createSettings(options);
-
+    assertTrue(settings.getQuoteAllFields());
     assertEquals('~', settings.getFormat().getQuoteEscape());
     assertEquals("\r\n", settings.getFormat().getLineSeparatorString());
     assertEquals('"', settings.getFormat().getQuote());

core/src/test/java/tech/tablesaw/io/csv/CsvWriterTest.java

@@ -20,4 +20,16 @@ public void toWriterWithExtension() throws IOException {
     table.write().toWriter(writer, "csv");
     assertEquals("colA,colB\na,1\nb,2\n", writer.toString().replaceAll("\\r\\n", "\n"));
   }
+
+  @Test
+  public void quoteAll() throws IOException {
+    StringColumn colA = StringColumn.create("colA", ImmutableList.of("a", "b"));
+    StringColumn colB = StringColumn.create("colB", ImmutableList.of("1", "2"));
+    Table table = Table.create("testTable", colA, colB);
+    StringWriter writer = new StringWriter();
+    table.write().usingOptions(CsvWriteOptions.builder(writer).quoteAllFields(true).build());
+    assertEquals(
+        "\"colA\",\"colB\"\n\"a\",\"1\"\n\"b\",\"2\"\n",
+        writer.toString().replaceAll("\\r\\n", "\n"));
+  }
 }