Increase Test Coverage

src/main/java/org/mybatis/dynamic/sql/delete/DeleteDSL.java

@@ -27,6 +27,7 @@
 import org.mybatis.dynamic.sql.common.OrderByModel;
 import org.mybatis.dynamic.sql.configuration.StatementConfiguration;
 import org.mybatis.dynamic.sql.util.Buildable;
+import org.mybatis.dynamic.sql.util.Utilities;
 import org.mybatis.dynamic.sql.where.AbstractWhereFinisher;
 import org.mybatis.dynamic.sql.where.AbstractWhereStarter;
 import org.mybatis.dynamic.sql.where.WhereModel;
@@ -50,9 +51,7 @@ private DeleteDSL(SqlTable table, String tableAlias, Function<DeleteModel, R> ad
 
     @Override
     public DeleteWhereBuilder where() {
-        if (whereBuilder == null) {
-            whereBuilder = new DeleteWhereBuilder();
-        }
+        whereBuilder = Utilities.buildIfNecessary(whereBuilder, DeleteWhereBuilder::new);
         return whereBuilder;
     }
 

src/main/java/org/mybatis/dynamic/sql/select/QueryExpressionDSL.java

@@ -35,6 +35,7 @@
 import org.mybatis.dynamic.sql.select.join.JoinSpecification;
 import org.mybatis.dynamic.sql.select.join.JoinType;
 import org.mybatis.dynamic.sql.util.Buildable;
+import org.mybatis.dynamic.sql.util.Utilities;
 import org.mybatis.dynamic.sql.where.AbstractWhereFinisher;
 import org.mybatis.dynamic.sql.where.AbstractWhereStarter;
 import org.mybatis.dynamic.sql.where.WhereModel;
@@ -68,9 +69,7 @@ protected QueryExpressionDSL(FromGatherer<R> fromGatherer, SqlTable table, Strin
 
     @Override
     public QueryExpressionWhereBuilder where() {
-        if (whereBuilder == null) {
-            whereBuilder = new QueryExpressionWhereBuilder();
-        }
+        whereBuilder = Utilities.buildIfNecessary(whereBuilder, QueryExpressionWhereBuilder::new);
         return whereBuilder;
     }
 

src/main/java/org/mybatis/dynamic/sql/update/UpdateDSL.java

@@ -39,6 +39,7 @@
 import org.mybatis.dynamic.sql.util.NullMapping;
 import org.mybatis.dynamic.sql.util.SelectMapping;
 import org.mybatis.dynamic.sql.util.StringConstantMapping;
+import org.mybatis.dynamic.sql.util.Utilities;
 import org.mybatis.dynamic.sql.util.ValueMapping;
 import org.mybatis.dynamic.sql.util.ValueOrNullMapping;
 import org.mybatis.dynamic.sql.util.ValueWhenPresentMapping;
@@ -70,10 +71,7 @@ public <T> SetClauseFinisher<T> set(SqlColumn<T> column) {
 
     @Override
     public UpdateWhereBuilder where() {
-        if (whereBuilder == null) {
-            whereBuilder = new UpdateWhereBuilder();
-        }
-
+        whereBuilder = Utilities.buildIfNecessary(whereBuilder, UpdateWhereBuilder::new);
         return whereBuilder;
     }
 

src/main/java/org/mybatis/dynamic/sql/util/Utilities.java

@@ -0,0 +1,28 @@
+/*
+ *    Copyright 2016-2023 the original author or authors.
+ *
+ *    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
+ *
+ *       https://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 org.mybatis.dynamic.sql.util;
+
+import java.util.function.Supplier;
+
+public interface Utilities {
+    static <T> T buildIfNecessary(T current, Supplier<T> builder) {
+        return current == null ? builder.get() : current;
+    }
+
+    static long safelyUnbox(Long l) {
+        return l == null ? 0 : l;
+    }
+}

src/main/java/org/mybatis/dynamic/sql/util/spring/NamedParameterJdbcTemplateExtensions.java

@@ -35,6 +35,7 @@
 import org.mybatis.dynamic.sql.update.UpdateModel;
 import org.mybatis.dynamic.sql.update.render.UpdateStatementProvider;
 import org.mybatis.dynamic.sql.util.Buildable;
+import org.mybatis.dynamic.sql.util.Utilities;
 import org.springframework.dao.EmptyResultDataAccessException;
 import org.springframework.jdbc.core.RowMapper;
 import org.springframework.jdbc.core.namedparam.BeanPropertySqlParameterSource;
@@ -57,7 +58,7 @@ public long count(SelectStatementProvider countStatement) {
         Long answer = template.queryForObject(countStatement.getSelectStatement(),
                 countStatement.getParameters(), Long.class);
 
-        return answer == null ? 0L : answer;
+        return Utilities.safelyUnbox(answer);
     }
 
     public int delete(Buildable<DeleteModel> deleteStatement) {

src/test/java/org/mybatis/dynamic/sql/util/UtilitiesTest.java

@@ -0,0 +1,28 @@
+/*
+ *    Copyright 2016-2023 the original author or authors.
+ *
+ *    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
+ *
+ *       https://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 org.mybatis.dynamic.sql.util;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.jupiter.api.Test;
+
+class UtilitiesTest {
+
+    @Test
+    void testUnboxWithNull() {
+        assertThat(Utilities.safelyUnbox(null)).isZero();
+    }
+}