Initial implementation of for and wait

This add forUpdate(), forShare(), etc. to the select DSL

Author: jeffgbutler

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

@@ -32,6 +32,7 @@
 import org.mybatis.dynamic.sql.select.QueryExpressionDSL.FromGatherer;
 import org.mybatis.dynamic.sql.util.Buildable;
 import org.mybatis.dynamic.sql.util.ConfigurableStatement;
+import org.mybatis.dynamic.sql.util.Validator;
 
 /**
  * Implements a SQL DSL for building select statements.
@@ -50,6 +51,8 @@ public class SelectDSL<R> implements Buildable<R>, ConfigurableStatement<SelectD
     private @Nullable Long offset;
     private @Nullable Long fetchFirstRows;
     final StatementConfiguration statementConfiguration = new StatementConfiguration();
+    private @Nullable String forClause;
+    private @Nullable String waitClause;
 
     private SelectDSL(Function<SelectModel, R> adapterFunction) {
         this.adapterFunction = Objects.requireNonNull(adapterFunction);
@@ -122,6 +125,42 @@ public FetchFirstFinisher<R> fetchFirstWhenPresent(@Nullable Long fetchFirstRows
         return () -> this;
     }
 
+    public SelectDSL<R> forUpdate() {
+        Validator.assertNull(forClause, "ERROR.48"); //$NON-NLS-1$
+        forClause = "for update"; //$NON-NLS-1$
+        return this;
+    }
+
+    public SelectDSL<R> forNoKeyUpdate() {
+        Validator.assertNull(forClause, "ERROR.48"); //$NON-NLS-1$
+        forClause = "for no key update"; //$NON-NLS-1$
+        return this;
+    }
+
+    public SelectDSL<R> forShare() {
+        Validator.assertNull(forClause, "ERROR.48"); //$NON-NLS-1$
+        forClause = "for share"; //$NON-NLS-1$
+        return this;
+    }
+
+    public SelectDSL<R> forKeyShare() {
+        Validator.assertNull(forClause, "ERROR.48"); //$NON-NLS-1$
+        forClause = "for key share"; //$NON-NLS-1$
+        return this;
+    }
+
+    public SelectDSL<R> skipLocked() {
+        Validator.assertNull(waitClause, "ERROR.49"); //$NON-NLS-1$
+        waitClause = "skip locked"; //$NON-NLS-1$
+        return this;
+    }
+
+    public SelectDSL<R> nowait() {
+        Validator.assertNull(waitClause, "ERROR.49"); //$NON-NLS-1$
+        waitClause = "nowait"; //$NON-NLS-1$
+        return this;
+    }
+
     @Override
     public SelectDSL<R> configureStatement(Consumer<StatementConfiguration> consumer) {
         consumer.accept(statementConfiguration);
@@ -134,6 +173,8 @@ public R build() {
                 .withOrderByModel(orderByModel)
                 .withPagingModel(buildPagingModel().orElse(null))
                 .withStatementConfiguration(statementConfiguration)
+                .withForClause(forClause)
+                .withWaitClause(waitClause)
                 .build();
         return adapterFunction.apply(selectModel);
     }

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

@@ -18,26 +18,40 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.stream.Stream;
 
+import org.jspecify.annotations.Nullable;
 import org.mybatis.dynamic.sql.render.RenderingStrategy;
 import org.mybatis.dynamic.sql.select.render.SelectRenderer;
 import org.mybatis.dynamic.sql.select.render.SelectStatementProvider;
 import org.mybatis.dynamic.sql.util.Validator;
 
 public class SelectModel extends AbstractSelectModel {
     private final List<QueryExpressionModel> queryExpressions;
+    private @Nullable final String forClause;
+    private @Nullable final String waitClause;
 
     private SelectModel(Builder builder) {
         super(builder);
         queryExpressions = Objects.requireNonNull(builder.queryExpressions);
         Validator.assertNotEmpty(queryExpressions, "ERROR.14"); //$NON-NLS-1$
+        forClause = builder.forClause;
+        waitClause = builder.waitClause;
     }
 
     public Stream<QueryExpressionModel> queryExpressions() {
         return queryExpressions.stream();
     }
 
+    public Optional<String> forClause() {
+        return Optional.ofNullable(forClause);
+    }
+
+    public Optional<String> waitClause() {
+        return Optional.ofNullable(waitClause);
+    }
+
     public SelectStatementProvider render(RenderingStrategy renderingStrategy) {
         return SelectRenderer.withSelectModel(this)
                 .withRenderingStrategy(renderingStrategy)
@@ -51,6 +65,8 @@ public static Builder withQueryExpressions(List<QueryExpressionModel> queryExpre
 
     public static class Builder extends AbstractBuilder<Builder> {
         private final List<QueryExpressionModel> queryExpressions = new ArrayList<>();
+        private @Nullable String forClause;
+        private @Nullable String waitClause;
 
         public Builder withQueryExpression(QueryExpressionModel queryExpression) {
             this.queryExpressions.add(queryExpression);
@@ -62,6 +78,16 @@ public Builder withQueryExpressions(List<QueryExpressionModel> queryExpressions)
             return this;
         }
 
+        public Builder withForClause(@Nullable String forClause) {
+            this.forClause = forClause;
+            return this;
+        }
+
+        public Builder withWaitClause(@Nullable String waitClause) {
+            this.waitClause = waitClause;
+            return this;
+        }
+
         @Override
         protected Builder getThis() {
             return this;

src/main/java/org/mybatis/dynamic/sql/select/render/SubQueryRenderer.java

@@ -16,7 +16,6 @@
 package org.mybatis.dynamic.sql.select.render;
 
 import java.util.Objects;
-import java.util.Optional;
 import java.util.stream.Collectors;
 
 import org.jspecify.annotations.Nullable;
@@ -48,8 +47,21 @@ public FragmentAndParameters render() {
                 .map(this::renderQueryExpression)
                 .collect(FragmentCollector.collect());
 
-        renderOrderBy().ifPresent(fragmentCollector::add);
-        renderPagingModel().ifPresent(fragmentCollector::add);
+        selectModel.orderByModel()
+                .map(this::renderOrderBy)
+                .ifPresent(fragmentCollector::add);
+
+        selectModel.pagingModel()
+                .map(this::renderPagingModel)
+                .ifPresent(fragmentCollector::add);
+
+        selectModel.forClause()
+                .map(FragmentAndParameters::fromFragment)
+                .ifPresent(fragmentCollector::add);
+
+        selectModel.waitClause()
+                .map(FragmentAndParameters::fromFragment)
+                .ifPresent(fragmentCollector::add);
 
         return fragmentCollector.toFragmentAndParameters(Collectors.joining(" ", prefix, suffix)); //$NON-NLS-1$
     }
@@ -61,18 +73,10 @@ private FragmentAndParameters renderQueryExpression(QueryExpressionModel queryEx
                 .render();
     }
 
-    private Optional<FragmentAndParameters> renderOrderBy() {
-        return selectModel.orderByModel().map(this::renderOrderBy);
-    }
-
     private FragmentAndParameters renderOrderBy(OrderByModel orderByModel) {
         return new OrderByRenderer(renderingContext).render(orderByModel);
     }
 
-    private Optional<FragmentAndParameters> renderPagingModel() {
-        return selectModel.pagingModel().map(this::renderPagingModel);
-    }
-
     private FragmentAndParameters renderPagingModel(PagingModel pagingModel) {
         return new PagingModelRenderer.Builder()
                 .withPagingModel(pagingModel)

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

@@ -17,6 +17,7 @@
 
 import java.util.Collection;
 
+import org.jspecify.annotations.Nullable;
 import org.mybatis.dynamic.sql.exception.InvalidSqlException;
 
 public class Validator {
@@ -49,4 +50,10 @@ public static void assertTrue(boolean condition, String messageNumber) {
     public static void assertTrue(boolean condition, String messageNumber, String p1) {
         assertFalse(!condition, messageNumber, p1);
     }
+
+    public static void assertNull(@Nullable Object object, String messageNumber) {
+        if (object != null) {
+            throw new InvalidSqlException(Messages.getString(messageNumber));
+        }
+    }
 }

src/main/resources/org/mybatis/dynamic/sql/util/messages.properties

@@ -64,4 +64,7 @@ ERROR.44={0} conditions must contain at least one value
 ERROR.45=You cannot call "on" in a Kotlin join expression more than once
 ERROR.46=At least one join criterion must render
 ERROR.47=A Kotlin case statement must specify a "then" clause for every "when" clause
+ERROR.48=You cannot call more than one of "forUpdate", "forNoKeyUpdate", "forShare", or "forKeyShare" in a select \
+  statement
+ERROR.49=You cannot call more than one of "skipLocked", or "nowait" in a select statement
 INTERNAL.ERROR=Internal Error {0}