Prefer Sets#intersection over more contrived alternatives.

PicnicSupermarket · May 1, 2023 · 5b58f40 · 5b58f40
1 parent f675cf0
commit 5b58f40
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diff --git a/...r-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ImmutableSetRules.java b/...r-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ImmutableSetRules.java
@@ -6,6 +6,8 @@
 import static java.util.Collections.singleton;
 
 import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.SetMultimap;
+import com.google.common.collect.Sets;
 import com.google.common.collect.Sets.SetView;
 import com.google.common.collect.Streams;
 import com.google.errorprone.refaster.Refaster;
@@ -15,6 +17,7 @@
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Iterator;
+import java.util.Map;
 import java.util.Set;
 import java.util.stream.Stream;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
@@ -211,4 +214,43 @@ ImmutableSet<T> after(T e1, T e2, T e3, T e4, T e5) {
       return ImmutableSet.of(e1, e2, e3, e4, e5);
     }
   }
+
+  /** Prefer {@link Sets#intersection(Set, Set)} ()} over more contrived alternatives. */
+  static final class SetsIntersection<T> {
+    @BeforeTemplate
+    ImmutableSet<T> before(Set<T> set1, Set<T> set2) {
+      return set1.stream().filter(set2::contains).collect(toImmutableSet());
+    }
+
+    @AfterTemplate
+    ImmutableSet<T> after(Set<T> set1, Set<T> set2) {
+      return Sets.intersection(set1, set2).immutableCopy();
+    }
+  }
+
+  /** Prefer {@link Sets#intersection(Set, Set)} ()} over more contrived alternatives. */
+  static final class MapKeySetIntersection<K, V> {
+    @BeforeTemplate
+    ImmutableSet<K> before(Set<K> set, Map<K, V> map) {
+      return set.stream().filter(map::containsKey).collect(toImmutableSet());
+    }
+
+    @AfterTemplate
+    ImmutableSet<K> after(Set<K> set, Map<K, V> map) {
+      return Sets.intersection(set, map.keySet()).immutableCopy();
+    }
+  }
+
+  /** Prefer {@link Sets#intersection(Set, Set)} ()} over more contrived alternatives. */
+  static final class SetMultimapKeySetIntersection<K, V> {
+    @BeforeTemplate
+    ImmutableSet<K> before(Set<K> set, SetMultimap<K, V> setMultimap) {
+      return set.stream().filter(setMultimap::containsKey).collect(toImmutableSet());
+    }
+
+    @AfterTemplate
+    ImmutableSet<K> after(Set<K> set, SetMultimap<K, V> setMultimap) {
+      return Sets.intersection(set, setMultimap.keySet()).immutableCopy();
+    }
+  }
 }
diff --git a/...b/src/test/resources/tech/picnic/errorprone/refasterrules/ImmutableSetRulesTestInput.java b/...b/src/test/resources/tech/picnic/errorprone/refasterrules/ImmutableSetRulesTestInput.java
@@ -3,7 +3,9 @@
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
 
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.ImmutableSetMultimap;
 import com.google.common.collect.Sets;
 import com.google.common.collect.Streams;
 import java.util.Arrays;
@@ -72,4 +74,21 @@ Set<Integer> testImmutableSetOf4() {
   Set<Integer> testImmutableSetOf5() {
     return Set.of(1, 2, 3, 4, 5);
   }
+
+  ImmutableSet<Integer> testSetsIntersection() {
+    ImmutableSet<Integer> set = ImmutableSet.of(1);
+    return ImmutableSet.of(1, 2, 3).stream().filter(set::contains).collect(toImmutableSet());
+  }
+
+  ImmutableSet<Integer> testMapKeySetIntersection() {
+    ImmutableMap<Integer, Integer> map = ImmutableMap.of(1, 4);
+    return ImmutableSet.of(1, 2, 3).stream().filter(map::containsKey).collect(toImmutableSet());
+  }
+
+  ImmutableSet<Integer> testSetMultimapKeySetIntersection() {
+    ImmutableSetMultimap<Integer, Integer> setMultiMap = ImmutableSetMultimap.of(1, 4);
+    return ImmutableSet.of(1, 2, 3).stream()
+        .filter(setMultiMap::containsKey)
+        .collect(toImmutableSet());
+  }
 }
diff --git a/.../src/test/resources/tech/picnic/errorprone/refasterrules/ImmutableSetRulesTestOutput.java b/.../src/test/resources/tech/picnic/errorprone/refasterrules/ImmutableSetRulesTestOutput.java
@@ -3,7 +3,9 @@
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
 
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.ImmutableSetMultimap;
 import com.google.common.collect.Sets;
 import com.google.common.collect.Streams;
 import java.util.Arrays;
@@ -67,4 +69,19 @@ Set<Integer> testImmutableSetOf4() {
   Set<Integer> testImmutableSetOf5() {
     return ImmutableSet.of(1, 2, 3, 4, 5);
   }
+
+  ImmutableSet<Integer> testSetsIntersection() {
+    ImmutableSet<Integer> set = ImmutableSet.of(1);
+    return Sets.intersection(ImmutableSet.of(1, 2, 3), set).immutableCopy();
+  }
+
+  ImmutableSet<Integer> testMapKeySetIntersection() {
+    ImmutableMap<Integer, Integer> map = ImmutableMap.of(1, 4);
+    return Sets.intersection(ImmutableSet.of(1, 2, 3), map.keySet()).immutableCopy();
+  }
+
+  ImmutableSet<Integer> testSetMultimapKeySetIntersection() {
+    ImmutableSetMultimap<Integer, Integer> setMultiMap = ImmutableSetMultimap.of(1, 4);
+    return Sets.intersection(ImmutableSet.of(1, 2, 3), setMultiMap.keySet()).immutableCopy();
+  }
 }