Implemented #42

release-notes/VERSION

@@ -3,6 +3,7 @@ Version: 2.4.0 (xx-xxx-2014)
 
 #32: Allow disabling of quoteChar
  (suggested by Jason D)
+#40: Allow (re)ordering of columns of Schema, using `CsvSchema.sortedBy(...)`
 
 ------------------------------------------------------------------------
 === History: ===

src/main/java/com/fasterxml/jackson/dataformat/csv/CsvFactory.java

@@ -389,6 +389,7 @@ protected CsvParser _createParser(byte[] data, int offset, int len, IOContext ct
                 _objectCodec, _createReader(data, offset, len, null, ctxt));
     }
 
+    @Override
     protected CsvParser _createParser(char[] data, int offset, int len, IOContext ctxt,
             boolean recyclable) throws IOException {
         return new CsvParser(ctxt, _getBufferRecycler(), _parserFeatures, _csvParserFeatures,

src/main/java/com/fasterxml/jackson/dataformat/csv/CsvSchema.java

@@ -141,6 +141,9 @@ public enum ColumnType
         ;
     }
 
+    /**
+     * Representation of info for a single column
+     */
     public static class Column
     {
         private final String _name;
@@ -334,7 +337,7 @@ protected void _checkIndex(int index) {
             }
         }
     }
-    
+
     /*
     /**********************************************************************
     /* Configuration, construction
@@ -407,7 +410,22 @@ protected CsvSchema(Column[] columns,
         _lineSeparator = lineSeparator;
         _columnsByName = columnsByName;
     }    
-
+
+    /**
+     * Copy constructor used for creating variants using
+     * <code>sortedBy()</code> methods.
+     */
+    protected CsvSchema(CsvSchema base, Column[] columns) {
+        _columns = columns;
+        _useHeader = base._useHeader;
+        _skipFirstDataRow = base._skipFirstDataRow;
+        _columnSeparator = base._columnSeparator;
+        _quoteChar = base._quoteChar;
+        _escapeChar = base._escapeChar;
+        _lineSeparator = base._lineSeparator;
+        _columnsByName = base._columnsByName;
+    }
+
     public static Builder builder() {
         return new Builder();
     }
@@ -442,6 +460,12 @@ public Builder rebuild() {
         return new Builder(this);
     }
 
+    /*
+    /**********************************************************************
+    /* Mutant factories
+    /**********************************************************************
+     */
+
     public CsvSchema withUseHeader(boolean state) {
         return (_useHeader == state) ? this
                 : new CsvSchema(_columns, state, _skipFirstDataRow,
@@ -512,6 +536,49 @@ public CsvSchema withoutColumns() {
                 _columnSeparator, _quoteChar, _escapeChar, _lineSeparator, _columnsByName);
     }
 
+    /**
+     * Mutant factory method that will construct a new instance in which columns
+     * are sorted based on names given as argument. Columns not listed in argument
+     * will be sorted after those within list, using existing ordering.
+     *<p>
+     * For example, schema that has columns:
+     *<pre>"a", "d", "c", "b"
+     *</pre>
+     * ordered with <code>schema.sortedBy("a", "b");</code>
+     * would result instance that columns in order:
+     *<pre>"a", "b", "d", "c"
+     *</pre>
+     * 
+     * @since 2.4
+     */
+    public CsvSchema sortedBy(String... columnNames) {
+        LinkedHashMap<String,Column> map = new LinkedHashMap<String,Column>();
+        for (String colName : columnNames) {
+            Column col = _columnsByName.get(colName);
+            if (col != null) {
+                map.put(col.getName(), col);
+            }
+        }
+        for (Column col : _columns) {
+            map.put(col.getName(), col);
+        }
+        return new CsvSchema(this, map.values().toArray(new Column[map.size()]));
+    }
+
+    /**
+     * Mutant factory method that will construct a new instance in which columns
+     * are sorted using given {@link Comparator} over column names.
+     * 
+     * @since 2.4
+     */
+    public CsvSchema sortedBy(Comparator<String> cmp) {
+        TreeMap<String,Column> map = new TreeMap<String,Column>(cmp);
+        for (Column col : _columns) {
+            map.put(col.getName(), col);
+        }
+        return new CsvSchema(this, map.values().toArray(new Column[map.size()]));
+    }
+
     /*
     /**********************************************************************
     /* Public API, FormatSchema

src/test/java/com/fasterxml/jackson/dataformat/csv/ModuleTestBase.java

@@ -85,15 +85,17 @@ public String quote(String str) {
         return '"'+str+'"';
     }
 
-    protected void assertToken(JsonToken expToken, JsonToken actToken)
-    {
+    protected String aposToQuotes(String json) {
+        return json.replace("'", "\"");
+    }
+
+    protected void assertToken(JsonToken expToken, JsonToken actToken) {
         if (actToken != expToken) {
             fail("Expected token "+expToken+", current token "+actToken);
         }
     }
 
-    protected void assertToken(JsonToken expToken, JsonParser jp)
-    {
+    protected void assertToken(JsonToken expToken, JsonParser jp) {
         assertToken(expToken, jp.getCurrentToken());
     }
 

src/test/java/com/fasterxml/jackson/dataformat/csv/TestSchema.java

@@ -1,11 +1,39 @@
 package com.fasterxml.jackson.dataformat.csv;
 
+import java.util.Collections;
+
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
 public class TestSchema extends ModuleTestBase
 {
+    @JsonPropertyOrder({ "a", "b", "c", "d" })
+    static class Mixed {
+        public int a, b, c, d;
+    }
+
     public void testSimpleWithAutoSchema() throws Exception
     {
         CsvMapper mapper = mapperForCsv();
         CsvSchema schema = mapper.schemaFor(FiveMinuteUser.class);
         assertEquals("[\"firstName\",\"lastName\",\"gender\",\"verified\",\"userImage\"]", schema.getColumnDesc());
     }
+
+    // for [Issue#42]
+    public void testReorderByName() throws Exception
+    {
+        CsvMapper mapper = mapperForCsv();
+        CsvSchema schema = mapper.schemaFor(Mixed.class);
+        assertEquals(aposToQuotes("['a','b','c','d']"), schema.getColumnDesc());
+        schema = schema.sortedBy("b", "c");
+        assertEquals(aposToQuotes("['b','c','a','d']"), schema.getColumnDesc());
+    }
+
+    // for [Issue#42]
+    public void testReorderWithComparator() throws Exception
+    {
+        CsvMapper mapper = mapperForCsv();
+        CsvSchema schema = mapper.schemaFor(Mixed.class);
+        schema = schema.sortedBy(Collections.<String>reverseOrder());
+        assertEquals(aposToQuotes("['d','c','b','a']"), schema.getColumnDesc());
+    }
 }