Better Use of Optional

Author: jeffgbutler

src/main/java/org/mybatis/dynamic/sql/insert/render/GeneralInsertRenderer.java

@@ -40,8 +40,7 @@ private GeneralInsertRenderer(Builder builder) {
     public GeneralInsertStatementProvider render() {
         FieldAndValueCollector collector = model.columnMappings()
                 .map(m -> m.accept(visitor))
-                .filter(Optional::isPresent)
-                .map(Optional::get)
+                .flatMap(Optional::stream)
                 .collect(FieldAndValueCollector.collect());
 
         Validator.assertFalse(collector.isEmpty(), "ERROR.9"); //$NON-NLS-1$

src/main/java/org/mybatis/dynamic/sql/insert/render/InsertRenderer.java

@@ -35,8 +35,7 @@ private InsertRenderer(Builder<T> builder) {
     public InsertStatementProvider<T> render() {
         FieldAndValueCollector collector = model.columnMappings()
                 .map(m -> m.accept(visitor))
-                .filter(Optional::isPresent)
-                .map(Optional::get)
+                .flatMap(Optional::stream)
                 .collect(FieldAndValueCollector.collect());
 
         Validator.assertFalse(collector.isEmpty(), "ERROR.10"); //$NON-NLS-1$

src/main/java/org/mybatis/dynamic/sql/update/render/UpdateRenderer.java

@@ -85,8 +85,7 @@ private FragmentAndParameters calculateSetPhrase() {
                 "ERROR.18"); //$NON-NLS-1$
 
         FragmentCollector fragmentCollector = fragmentsAndParameters.stream()
-                .filter(Optional::isPresent)
-                .map(Optional::get)
+                .flatMap(Optional::stream)
                 .collect(FragmentCollector.collect());
 
         return toSetPhrase(fragmentCollector);

src/main/java/org/mybatis/dynamic/sql/where/render/CriterionRenderer.java

@@ -135,8 +135,7 @@ private FragmentAndParameters renderExists(ExistsCriterion criterion) {
 
     private List<RenderedCriterion> renderSubCriteria(List<AndOrCriteriaGroup> subCriteria) {
         return subCriteria.stream().map(this::renderAndOrCriteriaGroup)
-                .filter(Optional::isPresent)
-                .map(Optional::get)
+                .flatMap(Optional::stream)
                 .collect(Collectors.toList());
     }