Add NumericOverflowException, thrown if sum overflows.

Author: greenrobot-team

objectbox-java/src/main/java/io/objectbox/exception/NumericOverflowException.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2019 ObjectBox Ltd. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.objectbox.exception;
+
+/**
+ * Thrown if a property query aggregate function can not compute a result due to a number type overflowing.
+ */
+public class NumericOverflowException extends DbException {
+
+    public NumericOverflowException(String message) {
+        super(message);
+    }
+}

objectbox-java/src/main/java/io/objectbox/query/PropertyQuery.java

@@ -382,7 +382,13 @@ public Double findDouble() {
     }
 
 
-    /** Sums up all values for the given property over all Objects matching the query. */
+    /**
+     * Sums up all values for the given property over all Objects matching the query.
+     * <p>
+     * Note: throws {@link io.objectbox.exception.NumericOverflowException NumericOverflowException} if
+     * the sum exceeds the numbers {@link Long} can represent. This is different from Java arithmetic
+     * where it would "wrap around" (e.g. max. value + 1 = min. value).
+     */
     public long sum() {
         return (Long) query.callInReadTx(new Callable<Long>() {
             @Override

tests/objectbox-java-test/src/test/java/io/objectbox/query/PropertyQueryTest.java

@@ -19,6 +19,7 @@
 import io.objectbox.TestEntity;
 import io.objectbox.TestEntityCursor;
 import io.objectbox.exception.DbException;
+import io.objectbox.exception.NumericOverflowException;
 import io.objectbox.query.QueryBuilder.StringOrder;
 import org.junit.Rule;
 import org.junit.Test;
@@ -640,7 +641,7 @@ public void sum_byteShortIntOverflow() {
 
     @Test
     public void sum_longOverflow_exception() {
-        exceptionRule.expect(DbException.class);
+        exceptionRule.expect(NumericOverflowException.class);
         exceptionRule.expectMessage("Numeric overflow");
 
         putTestEntityInteger((byte) 0, (short) 0, 0, Long.MAX_VALUE);