Ability to create table instances with new names

This is to more easily support sharding - we
can create multiple new table objects with
differing names, but other attributes the same.

Or, we can create a table object with a supplier
function that will change the table name
at render time. This capability is NOT thread safe.

Author: jeffgbutler

src/main/java/org/mybatis/dynamic/sql/AliasableSqlTable.java

@@ -37,9 +37,40 @@ protected AliasableSqlTable(Supplier<String> tableNameSupplier, Supplier<T> cons
     public T withAlias(String alias) {
         T newTable = constructor.get();
         ((AliasableSqlTable<T>) newTable).tableAlias = alias;
+        newTable.nameSupplier = nameSupplier;
         return newTable;
     }
 
+    /**
+     * Returns a new instance of this table with the specified name supplier. All column instances are recreated.
+     * This is useful for sharding where the table name may change at runtime based on some sharding algorithm,
+     * but all other table attributes are the same. Use of a name supplier allows you to create one table
+     * instance with a dynamically changing table name. Be very careful with this usage - it is NOT
+     * thread safe unless the specified nameSupplier is thread safe.
+     *
+     * @param nameSupplier new name supplier for the table
+     * @return a new AliasableSqlTable with the specified nameSupplier, all other table attributes are copied
+     */
+    public T withNameSupplier(Supplier<String> nameSupplier) {
+        T newTable = constructor.get();
+        ((AliasableSqlTable<T>) newTable).tableAlias = tableAlias;
+        newTable.nameSupplier = Objects.requireNonNull(nameSupplier);
+        return newTable;
+    }
+
+    /**
+     * Returns a new instance of this table with the specified name. All column instances are recreated.
+     * This is useful for sharding where the table name may change at runtime based on some sharding algorithm,
+     * but all other table attributes are the same.
+     *
+     * @param name new name for the table
+     * @return a new AliasableSqlTable with the specified name, all other table attributes are copied
+     */
+    public T withName(String name) {
+        Objects.requireNonNull(name);
+        return withNameSupplier(() -> name);
+    }
+
     @Override
     public Optional<String> tableAlias() {
         return Optional.ofNullable(tableAlias);

src/main/java/org/mybatis/dynamic/sql/SqlTable.java

@@ -24,7 +24,7 @@
 
 public class SqlTable implements TableExpression {
 
-    private final Supplier<String> nameSupplier;
+    protected Supplier<String> nameSupplier;
 
     protected SqlTable(String tableName) {
         Objects.requireNonNull(tableName);