Annotated and Literal traits

rewrite-core/src/main/java/org/openrewrite/trait/TraitMatcher.java

@@ -32,6 +32,19 @@
 @Incubating(since = "8.30.0")
 public interface TraitMatcher<U extends Trait<?>> {
 
+    default U require(Tree tree, Cursor parent) {
+        return require(new Cursor(parent, tree));
+    }
+
+    default U require(Cursor cursor) {
+        return get(cursor).orElseThrow(() ->
+                new IllegalStateException("Expected this cursor to match the trait"));
+    }
+
+    default Optional<U> get(Tree tree, Cursor parent) {
+        return get(new Cursor(parent, tree));
+    }
+
     /**
      * Tests whether a tree at the cursor matches the trait, and if so, returns
      * a trait instance containing the semantic information represented by the tree.

rewrite-java/src/main/java/org/openrewrite/java/trait/Annotated.java

@@ -0,0 +1,98 @@
+/*
+ * Copyright 2024 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.trait;
+
+import lombok.RequiredArgsConstructor;
+import lombok.Value;
+import org.openrewrite.Cursor;
+import org.openrewrite.internal.lang.Nullable;
+import org.openrewrite.java.AnnotationMatcher;
+import org.openrewrite.java.tree.Expression;
+import org.openrewrite.java.tree.J;
+import org.openrewrite.trait.SimpleTraitMatcher;
+import org.openrewrite.trait.Trait;
+
+import java.util.Optional;
+
+@Value
+public class Annotated implements Trait<J.Annotation> {
+    Cursor cursor;
+
+    /**
+     * @param defaultAlias The name of the annotation attribute that is aliased to
+     *                     "value", if any.
+     * @return The attribute value.
+     */
+    public Optional<Literal> getDefaultAttribute(@Nullable String defaultAlias) {
+        if (getTree().getArguments() == null) {
+            return Optional.empty();
+        }
+        for (Expression argument : getTree().getArguments()) {
+            if (!(argument instanceof J.Assignment)) {
+                return new Literal.Matcher().get(argument, cursor);
+            }
+        }
+        Optional<Literal> valueAttr = getAttribute("value");
+        if (valueAttr.isPresent()) {
+            return valueAttr;
+        }
+        return defaultAlias != null ?
+                getAttribute(defaultAlias) :
+                Optional.empty();
+    }
+
+    public Optional<Literal> getAttribute(String attribute) {
+        if (getTree().getArguments() == null) {
+            return Optional.empty();
+        }
+        for (Expression argument : getTree().getArguments()) {
+            if (argument instanceof J.Assignment) {
+                J.Assignment assignment = (J.Assignment) argument;
+                if (assignment.getVariable() instanceof J.Identifier) {
+                    J.Identifier identifier = (J.Identifier) assignment.getVariable();
+                    if (identifier.getSimpleName().equals(attribute)) {
+                        return new Literal.Matcher().get(
+                                assignment.getAssignment(),
+                                new Cursor(cursor, argument)
+                        );
+                    }
+                }
+            }
+        }
+        return Optional.empty();
+    }
+
+    @RequiredArgsConstructor
+    public static class Matcher extends SimpleTraitMatcher<Annotated> {
+        private final AnnotationMatcher matcher;
+
+        public Matcher(String signature) {
+            this.matcher = new AnnotationMatcher(signature);
+        }
+
+        @Override
+        protected @Nullable Annotated test(Cursor cursor) {
+            Object value = cursor.getValue();
+            if (value instanceof J.Annotation) {
+                J.Annotation annotation = (J.Annotation) value;
+                if (matcher.matches(annotation)) {
+                    return new Annotated(cursor);
+                }
+            }
+            return null;
+        }
+    }
+}

rewrite-java/src/main/java/org/openrewrite/java/trait/Literal.java

@@ -0,0 +1,139 @@
+/*
+ * Copyright 2024 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.trait;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.JavaType;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+import org.openrewrite.Cursor;
+import org.openrewrite.internal.lang.Nullable;
+import org.openrewrite.java.tree.Expression;
+import org.openrewrite.java.tree.J;
+import org.openrewrite.trait.SimpleTraitMatcher;
+import org.openrewrite.trait.Trait;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static java.util.Collections.singletonList;
+import static java.util.Objects.requireNonNull;
+
+/**
+ * A literal in Java is either a {@link J.Literal} or a {@link J.NewArray}
+ * with a non-null initializer that itself literals or new arrays that recursively
+ * contain these constraints. In other languages this trait is inclusive
+ * of constructs like list or map literals.
+ */
+@RequiredArgsConstructor
+public class Literal implements Trait<Expression> {
+    @Getter
+    private final Cursor cursor;
+
+    private final ObjectMapper mapper;
+
+    public boolean isNull() {
+        return getTree() instanceof J.Literal && ((J.Literal) getTree()).getValue() == null;
+    }
+
+    public boolean isNotNull() {
+        return !isNull();
+    }
+
+    public <@Nullable T> T getValue(Class<T> type) {
+        return getValue(mapper.constructType(type));
+    }
+
+    public <@Nullable T> T getValue(TypeReference<T> type) {
+        return getValue(mapper.constructType(type));
+    }
+
+    public <@Nullable T> T getValue(JavaType type) {
+        Expression lit = getTree();
+        if (lit instanceof J.Literal) {
+            J.Literal literal = (J.Literal) lit;
+            if (literal.getValue() == null) {
+                //noinspection DataFlowIssue
+                return null;
+            } else if (type.isCollectionLikeType()) {
+                List<?> l = singletonList(literal.getValue());
+                return mapper.convertValue(l, type);
+            } else {
+                return mapper.convertValue(literal.getValue(), type);
+            }
+        } else if (lit instanceof J.NewArray) {
+            List<Object> untyped = untypedInitializerLiterals((J.NewArray) lit);
+            return mapper.convertValue(untyped, type);
+        }
+        //noinspection DataFlowIssue
+        return null;
+    }
+
+    private List<Object> untypedInitializerLiterals(J.NewArray newArray) {
+        List<Object> acc = new ArrayList<>();
+        for (Expression init : requireNonNull(newArray.getInitializer())) {
+            if (init instanceof J.Literal) {
+                acc.add(((J.Literal) init).getValue());
+            } else {
+                acc.add(untypedInitializerLiterals((J.NewArray) init));
+            }
+        }
+        return acc;
+    }
+
+    public static class Matcher extends SimpleTraitMatcher<Literal> {
+        private static final ObjectMapper DEFAULT_MAPPER = new ObjectMapper();
+
+        private ObjectMapper mapper = DEFAULT_MAPPER;
+
+        /**
+         * @param mapper A customized mapper, which should be rare,
+         *               but possibly when you want a custom type factory.
+         * @return This matcher with a customized mapper set.
+         */
+        public Matcher mapper(ObjectMapper mapper) {
+            this.mapper = mapper;
+            return this;
+        }
+
+        @Override
+        protected @Nullable Literal test(Cursor cursor) {
+            Object value = cursor.getValue();
+            return value instanceof J.Literal ||
+                   isNewArrayWithLiteralInitializer(value) ?
+                    new Literal(cursor, mapper) :
+                    null;
+        }
+
+        private boolean isNewArrayWithLiteralInitializer(Object value) {
+            if (value instanceof J.NewArray) {
+                List<Expression> init = ((J.NewArray) value).getInitializer();
+                if (init == null) {
+                    return false;
+                }
+                for (Expression expr : init) {
+                    if (!(expr instanceof J.Literal) &&
+                        !isNewArrayWithLiteralInitializer(expr)) {
+                        return false;
+                    }
+                }
+                return true;
+            }
+            return false;
+        }
+    }
+}

rewrite-java/src/main/java/org/openrewrite/java/trait/Traits.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2024 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.trait;
+
+import org.openrewrite.java.AnnotationMatcher;
+import org.openrewrite.java.MethodMatcher;
+
+public class Traits {
+
+    public static Literal.Matcher literal() {
+        return new Literal.Matcher();
+    }
+
+    public static VariableAccess.Matcher variableAccess() {
+        return new VariableAccess.Matcher();
+    }
+
+    public static MethodAccess.Matcher methodAccess(MethodMatcher matcher) {
+        return new MethodAccess.Matcher(matcher);
+    }
+
+    public static MethodAccess.Matcher methodAccess(String signature) {
+        return new MethodAccess.Matcher(signature);
+    }
+
+    public static Annotated.Matcher annotated(AnnotationMatcher matcher) {
+        return new Annotated.Matcher(matcher);
+    }
+
+    public static Annotated.Matcher annotated(String signature) {
+        return new Annotated.Matcher(signature);
+    }
+}

rewrite-java/src/test/java/org/openrewrite/java/trait/AnnotatedTest.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2024 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.trait;
+
+import org.junit.jupiter.api.Test;
+import org.openrewrite.marker.SearchResult;
+import org.openrewrite.test.RewriteTest;
+
+import static org.openrewrite.java.Assertions.java;
+import static org.openrewrite.java.trait.Traits.annotated;
+
+class AnnotatedTest implements RewriteTest {
+
+    @Test
+    void attributes() {
+        rewriteRun(
+          spec -> spec.recipe(RewriteTest.toRecipe(() ->
+            annotated("@Example").asVisitor(a -> SearchResult.found(a.getTree(),
+              a.getDefaultAttribute("name")
+                .map(lit -> lit.getValue(String.class))
+                .orElse("unknown"))
+            )
+          )),
+          java(
+            """
+              import java.lang.annotation.Repeatable;
+              @Repeatable
+              @interface Example {
+                  String value() default "";
+                  String name() default "";
+              }
+              """
+          ),
+          java(
+            """
+              @Example("test")
+              @Example(value = "test")
+              @Example(name = "test")
+              class Test {
+              }
+              """,
+            """
+              /*~~(test)~~>*/@Example("test")
+              /*~~(test)~~>*/@Example(value = "test")
+              /*~~(test)~~>*/@Example(name = "test")
+              class Test {
+              }
+              """
+          )
+        );
+    }
+}