Use CollectionUtils for empty check

Author: abh1sar

engine/schema/src/main/java/com/cloud/storage/dao/VMTemplatePoolDaoImpl.java

@@ -153,7 +153,7 @@ public VMTemplateStoragePoolVO findByPoolTemplate(long poolId, long templateId,
     @Override
     public List<VMTemplateStoragePoolVO> listByPoolIdsAndTemplate(List<Long> poolIds, Long templateId) {
         SearchCriteria<VMTemplateStoragePoolVO> sc = PoolTemplateSearch.create();
-        if (poolIds != null && !poolIds.isEmpty()) {
+        if (CollectionUtils.isNotEmpty(poolIds)) {
             sc.setParameters("pool_id", poolIds.toArray());
         }
         sc.setParameters("template_id", templateId);

server/src/main/java/com/cloud/template/HypervisorTemplateAdapter.java

@@ -627,7 +627,7 @@ public boolean delete(TemplateProfile profile) {
 
                 boolean dataDiskDeletetionResult = true;
                 List<VMTemplateVO> dataDiskTemplates = templateDao.listByParentTemplatetId(template.getId());
-                if (dataDiskTemplates != null && dataDiskTemplates.size() > 0) {
+                if (CollectionUtils.isNotEmpty(dataDiskTemplates)) {
                     logger.info("Template: {} has Datadisk template(s) associated with it. Delete Datadisk templates before deleting the template", template);
                     for (VMTemplateVO dataDiskTemplate : dataDiskTemplates) {
                         logger.info("Delete Datadisk template: {} from image store: {}", dataDiskTemplate, imageStore);
@@ -708,7 +708,7 @@ public boolean delete(TemplateProfile profile) {
 
             // find all eligible image stores for this template
             List<DataStore> iStores = templateMgr.getImageStoreByTemplate(template.getId(), null);
-            if (iStores == null || iStores.size() == 0) {
+            if (CollectionUtils.isEmpty(iStores)) {
                 // remove any references from template_zone_ref
                 List<VMTemplateZoneVO> templateZones = templateZoneDao.listByTemplateId(template.getId());
                 if (templateZones != null) {

server/src/main/java/com/cloud/template/TemplateManagerImpl.java

@@ -1059,7 +1059,7 @@ public List<VMTemplateStoragePoolVO> getUnusedTemplatesInPool(StoragePoolVO pool
     @Override
     public void evictTemplateFromStoragePoolsForZones(Long templateId, List<Long> zoneIds) {
         List<Long> poolIds = new ArrayList<>();
-        if (zoneIds != null && !zoneIds.isEmpty()) {
+        if (CollectionUtils.isNotEmpty(zoneIds)) {
             List<StoragePoolVO> pools = _poolDao.listByDataCenterIds(zoneIds);
             poolIds = pools.stream().map(StoragePoolVO::getId).collect(Collectors.toList());
         }