IPP: new "Replace with 'Arrays.asList()'" intention (IDEA-167803)

plugins/IntentionPowerPak/src/META-INF/IntentionPowerPack.xml

@@ -516,5 +516,10 @@
       <bundleName>com.siyeh.IntentionPowerPackBundle</bundleName>
       <categoryKey>intention.category.other</categoryKey>
     </intentionAction>
+    <intentionAction>
+      <className>com.siyeh.ipp.collections.ReplaceWithArraysAsListIntention</className>
+      <bundleName>com.siyeh.IntentionPowerPackBundle</bundleName>
+      <categoryKey>intention.category.other</categoryKey>
+    </intentionAction>
   </extensions>
 </idea-plugin>

plugins/IntentionPowerPak/src/com/siyeh/IntentionPowerPackBundle.properties

@@ -158,6 +158,8 @@ objects.require.non.null.intention.family.name=Use 'java.util.Objects.requireNon
 postfix.prefix.intention.family.name=Flip prefix/postfix expression
 replace.conditional.with.boolean.expression.intention.family.name=Replace conditional expression with boolean expression
 replace.conditional.with.boolean.expression.intention.name=Replace '?:' with boolean expression
+replace.with.arrays.as.list.intention.name=Replace with 'Arrays.asList()'
+replace.with.arrays.as.list.intention.family.name=Replace with 'Arrays.asList()'
 
 #hand made
 demorgans.intention.name1=Replace '\\&\\&' with '||'

plugins/IntentionPowerPak/src/com/siyeh/ipp/collections/ReplaceWithArraysAsListIntention.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2000-2017 JetBrains s.r.o.
+ *
+ * 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
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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 com.siyeh.ipp.collections;
+
+import com.intellij.psi.*;
+import com.siyeh.ig.PsiReplacementUtil;
+import com.siyeh.ipp.base.Intention;
+import com.siyeh.ipp.base.PsiElementPredicate;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * @author Bas Leijdekkers
+ */
+public class ReplaceWithArraysAsListIntention extends Intention {
+
+  @NotNull
+  @Override
+  protected PsiElementPredicate getElementPredicate() {
+    return e -> {
+      if (!(e instanceof PsiMethodCallExpression)) {
+        return false;
+      }
+      final PsiMethodCallExpression methodCallExpression = (PsiMethodCallExpression)e;
+      final PsiMethod method = methodCallExpression.resolveMethod();
+      if (method == null) {
+        return false;
+      }
+      final String name = method.getName();
+      if (!name.equals("emptyList") && !name.equals("singletonList")) {
+        return false;
+      }
+      final PsiClass aClass = method.getContainingClass();
+      if (aClass == null) {
+        return false;
+      }
+      final String qualifiedName = aClass.getQualifiedName();
+      return qualifiedName != null && qualifiedName.equals("java.util.Collections");
+    };
+  }
+
+  @Override
+  protected void processIntention(@NotNull PsiElement element) {
+    final PsiMethodCallExpression methodCallExpression = (PsiMethodCallExpression)element;
+    final PsiExpressionList argumentList = methodCallExpression.getArgumentList();
+    PsiReplacementUtil.replaceExpressionAndShorten(methodCallExpression, "java.util.Arrays.asList" + argumentList.getText());
+  }
+}

plugins/IntentionPowerPak/src/intentionDescriptions/ReplaceWithArraysAsListIntention/after.java.template

@@ -0,0 +1,7 @@
+import java.util.*;
+
+public class X {
+  List<String> f() {
+    return Arrays.asList();
+  }
+}

plugins/IntentionPowerPak/src/intentionDescriptions/ReplaceWithArraysAsListIntention/before.java.template

@@ -0,0 +1,7 @@
+import java.util.*;
+
+public class X {
+  List<String> f() {
+    return <spot>Collections.emptyList()</spot>;
+  }
+}

plugins/IntentionPowerPak/src/intentionDescriptions/ReplaceWithArraysAsListIntention/description.html

@@ -0,0 +1,5 @@
+<html>
+<body>
+Replaces a <b>Collections.emptyList()</b> or <b>Collections.singletonList()</b> call with a call to <b>Arrays.asList()</b>.
+</body>
+</html>

plugins/IntentionPowerPak/testSrc/com/siyeh/ipp/collections/ReplaceWithArraysAsListIntentionTest.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2000-2017 JetBrains s.r.o.
+ *
+ * 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
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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 com.siyeh.ipp.collections;
+
+import com.siyeh.ipp.IPPTestCase;
+
+/**
+ * @author Bas Leijdekkers
+ */
+public class ReplaceWithArraysAsListIntentionTest extends IPPTestCase {
+
+  public void testBrokenCode() {
+    doTest(
+      "import java.util.*;" +
+      "class X {" +
+      "  List<String> f() {" +
+      "    return Collections.emptyList(\"text\"/*_Replace with 'Arrays.asList()'*/);" +
+      "  }" +
+      "}",
+
+      "import java.util.*;" +
+      "class X {" +
+      "  List<String> f() {" +
+      "    return Arrays.asList(\"text\");" +
+      "  }" +
+      "}"
+    );
+  }
+
+  public void testReplaceSingletonList() {
+    doTest(
+      "import java.util.*;" +
+      "class X {" +
+      "  List<String> f() {" +
+      "    return Collections.singletonList(\"text\"/*_Replace with 'Arrays.asList()'*/);" +
+      "  }" +
+      "}",
+
+      "import java.util.*;" +
+      "class X {" +
+      "  List<String> f() {" +
+      "    return Arrays.asList(\"text\");" +
+      "  }" +
+      "}"
+    );
+  }
+}