From ee8a326dd7c75f200df1d16f4163b56d73719798 Mon Sep 17 00:00:00 2001
From: Jonathan Schneider <jkschneider@gmail.com>
Date: Wed, 16 Jun 2021 14:02:06 -0700
Subject: [PATCH] NoGuavaSetsNewHashSet

---
 .../migrate/guava/NoGuavaSetsNewHashSet.java  | 76 +++++++++++++++++++
 .../guava/NoGuavaSetsNewHashSetTest.kt        | 75 ++++++++++++++++++
 2 files changed, 151 insertions(+)
 create mode 100644 src/main/java/org/openrewrite/java/migrate/guava/NoGuavaSetsNewHashSet.java
 create mode 100644 src/test/kotlin/org/openrewrite/java/migrate/guava/NoGuavaSetsNewHashSetTest.kt

diff --git a/src/main/java/org/openrewrite/java/migrate/guava/NoGuavaSetsNewHashSet.java b/src/main/java/org/openrewrite/java/migrate/guava/NoGuavaSetsNewHashSet.java
new file mode 100644
index 0000000000..bd57c1e114
--- /dev/null
+++ b/src/main/java/org/openrewrite/java/migrate/guava/NoGuavaSetsNewHashSet.java
@@ -0,0 +1,76 @@
+/*
+ * Copyright 2021 the original author or authors.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.openrewrite.java.migrate.guava;
+
+import org.openrewrite.ExecutionContext;
+import org.openrewrite.Recipe;
+import org.openrewrite.TreeVisitor;
+import org.openrewrite.java.JavaIsoVisitor;
+import org.openrewrite.java.JavaTemplate;
+import org.openrewrite.java.JavaVisitor;
+import org.openrewrite.java.MethodMatcher;
+import org.openrewrite.java.search.UsesMethod;
+import org.openrewrite.java.tree.J;
+
+import java.util.stream.Collectors;
+
+public class NoGuavaSetsNewHashSet extends Recipe {
+    private static final MethodMatcher NEW_HASH_SET = new MethodMatcher("com.google.common.collect.Sets newHashSet(..)");
+
+    @Override
+    public String getDisplayName() {
+        return "Use `new HashSet<>()` instead of Guava";
+    }
+
+    @Override
+    public String getDescription() {
+        return "Prefer the Java standard library over third-party usage of Guava in simple cases like this.";
+    }
+
+    @Override
+    protected TreeVisitor<?, ExecutionContext> getApplicableTest() {
+        return new UsesMethod<>(NEW_HASH_SET);
+    }
+
+    @Override
+    protected TreeVisitor<?, ExecutionContext> getVisitor() {
+        return new JavaVisitor<ExecutionContext>() {
+            private final JavaTemplate newHashSet = template("new HashSet<>()")
+                    .imports("java.util.HashSet")
+                    .build();
+
+            @Override
+            public J visitMethodInvocation(J.MethodInvocation method, ExecutionContext executionContext) {
+                if (NEW_HASH_SET.matches(method)) {
+                    maybeRemoveImport("com.google.common.collect.Sets");
+                    maybeAddImport("java.util.HashSet");
+                    if(method.getArguments().isEmpty()) {
+                        return method.withTemplate(newHashSet, method.getCoordinates().replace());
+                    } else {
+                        maybeAddImport("java.util.Arrays");
+                        JavaTemplate newHashSetVarargs = template("new HashSet<>(Arrays.asList(" + method.getArguments().stream().map(a -> "#{any()}").collect(Collectors.joining(",")) + "))")
+                                .imports("java.util.Arrays")
+                                .imports("java.util.HashSet")
+                                .build();
+                        return method.withTemplate(newHashSetVarargs, method.getCoordinates().replace(),
+                                method.getArguments().toArray());
+                    }
+                }
+                return super.visitMethodInvocation(method, executionContext);
+            }
+        };
+    }
+}
diff --git a/src/test/kotlin/org/openrewrite/java/migrate/guava/NoGuavaSetsNewHashSetTest.kt b/src/test/kotlin/org/openrewrite/java/migrate/guava/NoGuavaSetsNewHashSetTest.kt
new file mode 100644
index 0000000000..0fbba35a11
--- /dev/null
+++ b/src/test/kotlin/org/openrewrite/java/migrate/guava/NoGuavaSetsNewHashSetTest.kt
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2021 the original author or authors.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.openrewrite.java.migrate.guava
+
+import org.junit.jupiter.api.Test
+import org.openrewrite.Recipe
+import org.openrewrite.java.JavaParser
+import org.openrewrite.java.JavaRecipeTest
+
+class NoGuavaSetsNewHashSetTest: JavaRecipeTest {
+    override val parser: JavaParser
+        get() = JavaParser.fromJavaVersion()
+            .logCompilationWarningsAndErrors(true)
+            .classpath("guava")
+            .build()
+
+    override val recipe: Recipe
+        get() = NoGuavaSetsNewHashSet()
+
+    @Test
+    fun replaceWithNewHashSet() = assertChanged(
+        before = """
+            import com.google.common.collect.*;
+            
+            import java.util.Set;
+            
+            class Test {
+                Set<Integer> cardinalsWorldSeries = Sets.newHashSet();
+            }
+        """,
+        after = """
+            import java.util.HashSet;
+            import java.util.Set;
+            
+            class Test {
+                Set<Integer> cardinalsWorldSeries = new HashSet<>();
+            }
+        """
+    )
+
+    @Test
+    fun replaceWithNewHashSetVarargs() = assertChanged(
+        before = """
+            import com.google.common.collect.*;
+            
+            import java.util.Set;
+            
+            class Test {
+                Set<Integer> cardinalsWorldSeries = Sets.newHashSet(2006, 2011);
+            }
+        """,
+        after = """
+            import java.util.Arrays;
+            import java.util.HashSet;
+            import java.util.Set;
+            
+            class Test {
+                Set<Integer> cardinalsWorldSeries = new HashSet<>(Arrays.asList(2006, 2011));
+            }
+        """
+    )
+}