Expose compiled SQL for SqlTemplate to improve transparency (#1610)

See #1609

The compiled SQL query is computed as soon as the template is created.
It can be exposed for inspection by users (e.g. logging).

Signed-off-by: Thomas Segismont <tsegismont@gmail.com>

Author: tsegismont

vertx-sql-client-templates/src/main/java/io/vertx/sqlclient/templates/SqlTemplate.java

@@ -67,6 +67,12 @@ static SqlTemplate<Map<String, Object>, SqlResult<Void>> forUpdate(SqlClient cli
     return new SqlTemplateImpl<>(client, sqlTemplate, query -> query.collecting(SqlTemplateImpl.NULL_COLLECTOR), sqlTemplate::mapTuple);
   }
 
+
+  /**
+   * @return the computed SQL for this template
+   */
+  String getSql();
+
   /**
    * Set a parameters user defined mapping function.
    *

vertx-sql-client-templates/src/main/java/io/vertx/sqlclient/templates/impl/SqlTemplateImpl.java

@@ -2,12 +2,7 @@
 
 import io.vertx.core.Future;
 import io.vertx.core.json.JsonObject;
-import io.vertx.sqlclient.PreparedQuery;
-import io.vertx.sqlclient.Row;
-import io.vertx.sqlclient.RowSet;
-import io.vertx.sqlclient.SqlClient;
-import io.vertx.sqlclient.SqlResult;
-import io.vertx.sqlclient.Tuple;
+import io.vertx.sqlclient.*;
 import io.vertx.sqlclient.templates.RowMapper;
 import io.vertx.sqlclient.templates.TupleMapper;
 
@@ -37,6 +32,11 @@ public SqlTemplateImpl(SqlClient client,
     this.tupleMapper = tupleMapper;
   }
 
+  @Override
+  public String getSql() {
+    return sqlTemplate.getSql();
+  }
+
   @Override
   public <T> io.vertx.sqlclient.templates.SqlTemplate<T, R> mapFrom(TupleMapper<T> mapper) {
     return new SqlTemplateImpl<>(client, sqlTemplate, queryMapper, params -> mapper.map(sqlTemplate, sqlTemplate.numberOfParams(), params));

vertx-sql-client-templates/src/test/java/io/vertx/tests/sqlclient/templates/PgTemplateTestBase.java

@@ -96,10 +96,12 @@ protected <P, T, V> void testGet(TestContext ctx,
                                    Function<T, V> extractor,
                                    String column) {
     Async async = ctx.async();
+    String query = "SELECT %s :: %s \"%s\"";
     SqlTemplate<P, RowSet<T>> template = SqlTemplate
-      .forQuery(connection, "SELECT #{" + paramName + "} :: " + sqlType + " \"" + column + "\"")
+      .forQuery(connection, String.format(query, "#{" + paramName + "}", sqlType, column))
       .mapFrom(paramsMapper)
       .mapTo(rowMapper);
+    ctx.assertEquals(String.format(query, "$1", sqlType, column), template.getSql());
     template
       .execute(params)
       .onComplete(ctx.asyncAssertSuccess(result -> {