add declaration and mutualize state

Author: luccailliau

index.d.ts

@@ -188,6 +188,8 @@ export interface ExecutionOptions {
 
   getTimestamp(): number | Long | undefined | null;
 
+  setTimestamp(timestamp: number | Long | undefined | null): void;
+
   setHints(hints: string[]): void;
 }
 

lib/execution-options.js

@@ -289,14 +289,23 @@ class ExecutionOptions {
 
   /**
    * Gets the provided timestamp for the execution in microseconds from the unix epoch (00:00:00, January 1st, 1970).
-   * <p>When a timestamp generator is used, this method returns <code>undefined</code>.</p>
    * @abstract
    * @returns {Number|Long|undefined|null}
    */
   getTimestamp() {
 
   }
 
+  /**
+   * Sets the provided timestamp for the execution in microseconds from the unix epoch (00:00:00, January 1st, 1970).
+   * @param {Number|Long|undefined|null} timestamp
+   * @abstract
+   * @ignore
+   */
+  setTimestamp(timestamp) {
+
+  }
+
   /**
    * @param {Array} hints
    * @abstract
@@ -376,6 +385,7 @@ class DefaultExecutionOptions extends ExecutionOptions {
     this._routingIndexes = this._queryOptions.routingIndexes;
     this._pageState = typeof this._queryOptions.pageState === 'string' ?
       utils.allocBufferFromString(this._queryOptions.pageState, 'hex') : this._queryOptions.pageState;
+    this._timestamp = queryOptions.timestamp;
     this._preferredHost = null;
 
     this._client = client;
@@ -498,10 +508,8 @@ class DefaultExecutionOptions extends ExecutionOptions {
       const generator = this._client.options.policies.timestampGeneration;
 
       if ( types.protocolVersion.supportsTimestamp(this._client.controlConnection.protocolVersion) && generator) {
-        if (this._generatedTimestamp === undefined) {
-          this._generatedTimestamp = generator.next(this._client);
-        }
-        result = this._generatedTimestamp;
+        result = generator.next(this._client);
+        this.setTimestamp(result);
       } else {
         result = null;
       }
@@ -562,7 +570,11 @@ class DefaultExecutionOptions extends ExecutionOptions {
   }
 
   getTimestamp() {
-    return this._queryOptions.timestamp;
+    return this._timestamp;
+  }
+
+  setTimestamp(timestamp) {
+    this._timestamp = timestamp;
   }
 
   /**