From 68000eb6fccd217e8f04c556cc2a1d4bacb5897a Mon Sep 17 00:00:00 2001
From: Lukas Eder <lukas.eder@gmail.com>
Date: Thu, 19 Aug 2021 11:21:02 +0200
Subject: [PATCH] [jOOQ/jOOQ#11120] Add DSLContext.fetchMap(ResultQuery<?
 extends Record2<K, V>>) and fetchGroups(ResultQuery<? extends Record2<K, V>>)

---
 jOOQ/src/main/java/org/jooq/DSLContext.java   | 49 +++++++++++++++++++
 .../java/org/jooq/impl/DefaultDSLContext.java | 15 ++++++
 2 files changed, 64 insertions(+)

diff --git a/jOOQ/src/main/java/org/jooq/DSLContext.java b/jOOQ/src/main/java/org/jooq/DSLContext.java
index 75e49c623a..5635b015e0 100644
--- a/jOOQ/src/main/java/org/jooq/DSLContext.java
+++ b/jOOQ/src/main/java/org/jooq/DSLContext.java
@@ -12607,6 +12607,55 @@ public interface DSLContext extends Scope {
     @Support
     <T> List<T> fetchValues(TableField<?, T> field) throws DataAccessException;
 
+    /**
+     * Execute the query and return a {@link Map} with the first column as the
+     * map key and the second column as the map value.
+     * <p>
+     * An exception is thrown, if the keys turn out to be non-unique in the
+     * result set. Use {@link #fetchGroups(ResultQuery)} instead, if your keys
+     * are non-unique.
+     * <p>
+     * Whether this fetches an intermediate {@link Result} (accessible by
+     * {@link ExecuteListener} implementations), or streams records directly to
+     * the collector producing the result is governed by
+     * {@link Settings#getFetchIntermediateResult()}.
+     * <p>
+     * The resulting map is iteration order preserving.
+     *
+     * @return A Map containing grouped results. This will never be
+     *         <code>null</code>.
+     * @throws DataAccessException if something went wrong executing the query
+     * @throws InvalidResultException if the key list is non-unique in the
+     *             result set.
+     * @see ResultQuery#fetchMap(Field, Field)
+     */
+    @NotNull
+    @Support
+    <K, V> Map<K, V> fetchMap(ResultQuery<? extends Record2<K, V>> query) throws DataAccessException;
+
+    /**
+     * Execute the query and return a {@link Map} with the first column as the
+     * map key and the second column as the map values.
+     * <p>
+     * Unlike {@link #fetchMap(ResultQuery)}, this method allows for non-unique
+     * keys in the result set.
+     * <p>
+     * Whether this fetches an intermediate {@link Result} (accessible by
+     * {@link ExecuteListener} implementations), or streams records directly to
+     * the collector producing the result is governed by
+     * {@link Settings#getFetchIntermediateResult()}.
+     * <p>
+     * The resulting map is iteration order preserving.
+     *
+     * @return A Map containing grouped results. This will never be
+     *         <code>null</code>.
+     * @throws DataAccessException if something went wrong executing the query
+     * @see ResultQuery#fetchGroups(Field, Field)
+     */
+    @NotNull
+    @Support
+    <K, V> Map<K, List<V>> fetchGroups(ResultQuery<? extends Record2<K, V>> query) throws DataAccessException;
+
     /**
      * Execute a "Query by Example" (QBE) based on an example record.
      *
diff --git a/jOOQ/src/main/java/org/jooq/impl/DefaultDSLContext.java b/jOOQ/src/main/java/org/jooq/impl/DefaultDSLContext.java
index c12b9812f8..0b77354310 100644
--- a/jOOQ/src/main/java/org/jooq/impl/DefaultDSLContext.java
+++ b/jOOQ/src/main/java/org/jooq/impl/DefaultDSLContext.java
@@ -41,6 +41,8 @@ import static java.util.Arrays.asList;
 import static java.util.Collections.emptyList;
 import static java.util.Collections.unmodifiableList;
 import static java.util.Collections.unmodifiableMap;
+import static org.jooq.Records.intoGroups;
+import static org.jooq.Records.intoMap;
 import static org.jooq.conf.ParamType.INLINED;
 import static org.jooq.conf.ParamType.NAMED;
 import static org.jooq.conf.ParamType.NAMED_OR_INLINED;
@@ -212,6 +214,7 @@ import org.jooq.Record6;
 import org.jooq.Record7;
 import org.jooq.Record8;
 import org.jooq.Record9;
+import org.jooq.Records;
 import org.jooq.RenderContext;
 import org.jooq.Result;
 import org.jooq.ResultQuery;
@@ -284,6 +287,8 @@ import org.jooq.tools.jdbc.MockDataProvider;
 import org.jooq.tools.jdbc.MockRunnable;
 import org.jooq.util.xml.jaxb.InformationSchema;
 
+import org.jetbrains.annotations.NotNull;
+
 import io.r2dbc.spi.ConnectionFactory;
 
 /**
@@ -4653,6 +4658,16 @@ public class DefaultDSLContext extends AbstractScope implements DSLContext, Seri
         return fetchValues(select(field).from(field.getTable()));
     }
 
+    @Override
+    public <K, V> Map<K, V> fetchMap(ResultQuery<? extends Record2<K, V>> query) {
+        return Tools.attach(query, configuration(), () -> query.collect(intoMap()));
+    }
+
+    @Override
+    public <K, V> Map<K, List<V>> fetchGroups(ResultQuery<? extends Record2<K, V>> query) {
+        return Tools.attach(query, configuration(), () -> query.collect(intoGroups()));
+    }
+
     private final <T, R extends Record1<T>> T value1(R record) {
         if (record == null)
             return null;