Count functions implement BindableColumn directly

Author: jeffgbutler

src/main/java/org/mybatis/dynamic/sql/select/aggregate/Count.java

@@ -15,24 +15,49 @@
  */
 package org.mybatis.dynamic.sql.select.aggregate;
 
+import java.sql.JDBCType;
+import java.util.Objects;
+import java.util.Optional;
+
 import org.mybatis.dynamic.sql.BasicColumn;
+import org.mybatis.dynamic.sql.BindableColumn;
+import org.mybatis.dynamic.sql.render.TableAliasCalculator;
+
+public class Count implements BindableColumn<Long> {
+
+    private final BasicColumn column;
+    private final String alias;
 
-public class Count extends AbstractAggregate<Count> {
-    
     private Count(BasicColumn column) {
-        super(column);
+        this.column = Objects.requireNonNull(column);
+        alias = null;
     }
-    
+
+    private Count(BasicColumn column, String alias) {
+        this.column = Objects.requireNonNull(column);
+        this.alias = alias;
+    }
+
     @Override
-    protected String render(String columnName) {
-        return "count(" + columnName + ")"; //$NON-NLS-1$ //$NON-NLS-2$
+    public String renderWithTableAlias(TableAliasCalculator tableAliasCalculator) {
+        return "count(" + column.renderWithTableAlias(tableAliasCalculator) + ")"; //$NON-NLS-1$ //$NON-NLS-2$
     }
 
     @Override
-    protected Count copy() {
-        return new Count(column);
+    public Optional<String> alias() {
+        return Optional.ofNullable(alias);
     }
-    
+
+    @Override
+    public Count as(String alias) {
+        return new Count(column, alias);
+    }
+
+    @Override
+    public Optional<JDBCType> jdbcType() {
+        return Optional.of(JDBCType.BIGINT);
+    }
+
     public static Count of(BasicColumn column) {
         return new Count(column);
     }

src/main/java/org/mybatis/dynamic/sql/select/aggregate/CountAll.java

@@ -15,24 +15,29 @@
  */
 package org.mybatis.dynamic.sql.select.aggregate;
 
+import java.sql.JDBCType;
 import java.util.Optional;
 
-import org.mybatis.dynamic.sql.BasicColumn;
+import org.mybatis.dynamic.sql.BindableColumn;
 import org.mybatis.dynamic.sql.render.TableAliasCalculator;
 
 /**
  * CountAll seems like the other aggregates, but it is special because there is no column.
  * Rather than dealing with a useless and confusing abstraction, we simply implement
- * BasicColumn directly.
+ * BindableColumn directly.
  *  
  * @author Jeff Butler
  */
-public class CountAll implements BasicColumn {
+public class CountAll implements BindableColumn<Long> {
 
-    private String alias;
+    private final String alias;
 
     public CountAll() {
-        super();
+        alias = null;
+    }
+
+    private CountAll(String alias) {
+        this.alias = alias;
     }
 
     @Override
@@ -47,8 +52,11 @@ public Optional<String> alias() {
 
     @Override
     public CountAll as(String alias) {
-        CountAll copy = new CountAll();
-        copy.alias = alias;
-        return copy;
+        return new CountAll(alias);
+    }
+
+    @Override
+    public Optional<JDBCType> jdbcType() {
+        return Optional.of(JDBCType.BIGINT);
     }
 }

src/main/java/org/mybatis/dynamic/sql/select/aggregate/CountDistinct.java

@@ -15,24 +15,49 @@
  */
 package org.mybatis.dynamic.sql.select.aggregate;
 
+import java.sql.JDBCType;
+import java.util.Objects;
+import java.util.Optional;
+
 import org.mybatis.dynamic.sql.BasicColumn;
+import org.mybatis.dynamic.sql.BindableColumn;
+import org.mybatis.dynamic.sql.render.TableAliasCalculator;
+
+public class CountDistinct implements BindableColumn<Long> {
+
+    private final BasicColumn column;
+    private final String alias;
 
-public class CountDistinct extends AbstractAggregate<CountDistinct> {
-    
     private CountDistinct(BasicColumn column) {
-        super(column);
+        this.column = Objects.requireNonNull(column);
+        alias = null;
     }
-    
+
+    private CountDistinct(BasicColumn column, String alias) {
+        this.column = Objects.requireNonNull(column);
+        this.alias = alias;
+    }
+
     @Override
-    protected String render(String columnName) {
-        return "count(distinct " + columnName + ")"; //$NON-NLS-1$ //$NON-NLS-2$
+    public String renderWithTableAlias(TableAliasCalculator tableAliasCalculator) {
+        return "count(distinct " + column.renderWithTableAlias(tableAliasCalculator) + ")"; //$NON-NLS-1$ //$NON-NLS-2$
     }
 
     @Override
-    protected CountDistinct copy() {
-        return new CountDistinct(column);
+    public Optional<String> alias() {
+        return Optional.ofNullable(alias);
     }
-    
+
+    @Override
+    public CountDistinct as(String alias) {
+        return new CountDistinct(column, alias);
+    }
+
+    @Override
+    public Optional<JDBCType> jdbcType() {
+        return Optional.of(JDBCType.BIGINT);
+    }
+
     public static CountDistinct of(BasicColumn column) {
         return new CountDistinct(column);
     }