added allowRetry AQL query option (DE-589)

Author: rashtao

src/main/java/com/arangodb/springframework/annotation/QueryOptions.java

@@ -20,6 +20,8 @@
 
 package com.arangodb.springframework.annotation;
 
+import com.arangodb.model.AqlQueryOptions;
+
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
@@ -140,4 +142,22 @@
 	 */
 	boolean allowDirtyRead() default false;
 
+    /**
+     * Set this option to true to make it possible to retry fetching the latest batch from a cursor.
+     * <p/>
+     * This makes possible to safely retry invoking {@link com.arangodb.ArangoCursor#next()} in
+     * case of I/O exceptions (which are actually thrown as {@link com.arangodb.ArangoDBException}
+     * with cause {@link java.io.IOException})
+     * <p/>
+     * If set to false (default), then it is not safe to retry invoking
+     * {@link com.arangodb.ArangoCursor#next()} in case of I/O exceptions, since the request to
+     * fetch the next batch is not idempotent (i.e. the cursor may advance multiple times on the
+     * server).
+     * <p/>
+     * Note: once you successfully received the last batch, you should call
+     * {@link com.arangodb.ArangoCursor#close()} so that the server does not unnecessary keep the
+     * batch until the cursor times out ({@link AqlQueryOptions#ttl(Integer)}).
+     */
+    boolean allowRetry() default false;
+
 }

src/main/java/com/arangodb/springframework/repository/query/ArangoQueryMethod.java

@@ -127,6 +127,9 @@ public AqlQueryOptions getAnnotatedQueryOptions() {
 		if (allowDirtyRead) {
 			options.allowDirtyRead(allowDirtyRead);
 		}
+		if (queryOptions.allowRetry()) {
+			options.allowRetry(true);
+		}
 		return options;
 	}
 

src/test/java/com/arangodb/springframework/repository/CustomerRepository.java

@@ -51,7 +51,7 @@ public interface CustomerRepository extends ArangoRepository<Customer, String>,
     @Query("FOR c IN #collection FILTER c._key == @id AND c.`customer-name` == @name RETURN c")
     ArangoCursor<Customer> findOneByBindVarsAql(AqlQueryOptions options, @BindVars Map<String, Object> bindVars);
 
-    @QueryOptions(count = true)
+    @QueryOptions(count = true, allowRetry = true)
     @Query("for i in @n..10000 return 1/i")
     ArangoCursor<Double> sequenceTo10K(@Param("n") Integer n, AqlQueryOptions options);