Javadoc

Author: vietj

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

@@ -5,12 +5,21 @@
 public interface SqlClientInternal extends SqlClient {
 
   /**
-   * Append a query placeholder in the {@code query}.
+   * Append a parameter placeholder in the {@code query}.
    *
-   * <p>The index starts at {@code 0}
+   * <p>The index starts at {@code 0}.
+   *
+   * <ul>
+   *   <li>When {@code index == current} indicates it is a new parameter and therefore the same
+   *    * value should be returned.</li>
+   *   <li>When {@code index < current} indicates the builder wants to reuse a parameter.
+   *   The implementation can either return the same value to indicate the parameter can be reused or
+   *   return the next index to use (which is shall be the {@code current} value</li>
+   * </ul>
    *
    * @param queryBuilder the builder to append to
-   * @param index the placeholder index
+   * @param index the parameter placeholder index
+   * @return the index at which the parameter placeholder could be added
    */
   int appendQueryPlaceholder(StringBuilder queryBuilder, int index, int current);