Allow selecting a column from a table

releases.moxie

@@ -15,6 +15,7 @@ r30: {
     changes: ~
     additions:
     - Added groupBy methods to QueryWhere (issue-20)
+    - Allow selecting a column from a table
     dependencyChanges: ~
     contributors:
     - James Moger

src/main/java/com/iciql/Db.java

@@ -140,6 +140,10 @@ public class Db implements AutoCloseable {
 		return x;
 	}
 
+	static <X> boolean isToken(X x) {
+		return TOKENS.containsKey(x);
+	}
+
 	static Token getToken(Object x) {
 		return TOKENS.get(x);
 	}

src/main/java/com/iciql/Query.java

@@ -389,9 +389,21 @@ public class Query<T> {
 	@SuppressWarnings("unchecked")
 	private <X, Z> List<X> select(Z x, boolean distinct) {
 		Class<?> clazz = x.getClass();
-		if (Utils.isSimpleType(clazz)) {
-			return selectSimple((X) x, distinct);
+		if (Db.isToken(x)) {
+			// selecting a function
+			return selectFunction((X) x, distinct);
+		} else {
+			// selecting a column
+			SelectColumn<T> col = getColumnByReference(x);
+			if (col == null) {
+				col = getColumnByReference(getPrimitiveAliasByValue(x));
+			}
+			if (col != null) {
+				return (List<X>) selectColumn(col, clazz, distinct);
+			}
 		}
+
+		// selecting into a new object type
 		Class<?> enclosingClass = clazz.getEnclosingClass();
 		if (enclosingClass != null) {
 			// anonymous inner class
@@ -426,18 +438,41 @@ public class Query<T> {
 	}
 
 	@SuppressWarnings("unchecked")
-	private <X> List<X> selectSimple(X x, boolean distinct) {
+	private <X> List<X> selectFunction(X x, boolean distinct) {
 		SQLStatement stat = getSelectStatement(distinct);
 		appendSQL(stat, null, x);
 		appendFromWhere(stat);
 		ResultSet rs = stat.executeQuery();
 		List<X> result = Utils.newArrayList();
-		Class<? extends DataTypeAdapter<?>> typeAdapter = Utils.getDataTypeAdapter(x.getClass().getAnnotations());
 		try {
 			// SQLite returns pre-closed ResultSets for query results with 0 rows
 			if (!rs.isClosed()) {
 				while (rs.next()) {
-					X value = (X) db.getDialect().deserialize(rs, 1, x.getClass(), typeAdapter);
+					X value = (X) rs.getObject(1);
+					result.add(value);
+				}
+			}
+		} catch (Exception e) {
+			throw IciqlException.fromSQL(stat.getSQL(), e);
+		} finally {
+			JdbcUtils.closeSilently(rs, true);
+		}
+		return result;
+	}
+
+	@SuppressWarnings("unchecked")
+	private <X> List<X> selectColumn(SelectColumn<T> col, Class<X> clazz, boolean distinct) {
+		SQLStatement stat = getSelectStatement(distinct);
+		col.appendSQL(stat);
+		appendFromWhere(stat);
+		ResultSet rs = stat.executeQuery();
+		List<X> result = Utils.newArrayList();
+		Class<? extends DataTypeAdapter<?>> typeAdapter = col.getFieldDefinition().typeAdapter;
+		try {
+			// SQLite returns pre-closed ResultSets for query results with 0 rows
+			if (!rs.isClosed()) {
+				while (rs.next()) {
+					X value = (X) db.getDialect().deserialize(rs, 1, clazz, typeAdapter);
 					result.add(value);
 				}
 			}

src/test/java/com/iciql/test/ModelsTest.java

@@ -160,4 +160,19 @@ public class ModelsTest {
 		SupportedTypes s2 = db.from(SupportedTypes.SAMPLE).where(SupportedTypes.SAMPLE.id).is(1).selectFirst();
 		assertEquals(40, s2.myString.length());
 	}
+
+	@Test
+	public void testColumnSelection() {
+		List<SupportedTypes> original = SupportedTypes.createList();
+		db.insertAll(original);
+		List<String> myStrings = db.from(SupportedTypes.SAMPLE)
+				.select(SupportedTypes.SAMPLE.myString);
+		assertEquals(10, myStrings.size());
+
+		List<Integer> ids = db.from(SupportedTypes.SAMPLE)
+				.orderByDesc(SupportedTypes.SAMPLE.id)
+				.selectDistinct(SupportedTypes.SAMPLE.id);
+		assertEquals(10, ids.size());
+		assertEquals("[9, 8, 7, 6, 5, 4, 3, 2, 1, 0]", ids.toString());
+	}
 }

src/test/java/com/iciql/test/PrimitivesTest.java

@@ -99,4 +99,21 @@ public class PrimitivesTest {
 		}
 		db.close();
 	}
+
+	@Test
+	public void testPrimitiveColumnSelection() {
+		Db db = IciqlSuite.openNewDb();
+
+		// insert random models in reverse order
+		List<PrimitivesModel> models = PrimitivesModel.getList();
+		PrimitivesModel model = models.get(0);
+		Collections.reverse(models);
+		// insert them in reverse order
+		db.insertAll(models);
+
+		PrimitivesModel p = new PrimitivesModel();
+		List<Long> list = db.from(p)/*.orderByDesc(p.myLong)*/.select(p.myLong);
+		assertEquals(models.size(), list.size());
+		assertEquals("[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]", list.toString());
+	}
 }