Update writing-a-java-refactoring-recipe.md example to use:

- available utils
- simpler streams
- direct `JavaTemplate` usage

Author: MBoegers

docs/authoring-recipes/writing-a-java-refactoring-recipe.md

@@ -465,80 +465,72 @@ With all of that done, the complete `SayHelloRecipe` looks like this:
 ```java
 package com.yourorg;
 
-import com.fasterxml.jackson.annotation.JsonCreator;
-import com.fasterxml.jackson.annotation.JsonProperty;
 import lombok.EqualsAndHashCode;
 import lombok.Value;
-import org.jspecify.annotations.NonNull;
-import org.openrewrite.*;
+import org.openrewrite.ExecutionContext;
+import org.openrewrite.Option;
+import org.openrewrite.Recipe;
+import org.openrewrite.TreeVisitor;
 import org.openrewrite.java.JavaIsoVisitor;
 import org.openrewrite.java.JavaTemplate;
 import org.openrewrite.java.tree.J;
+import org.openrewrite.java.tree.TypeUtils;
+
+import java.util.Comparator;
 
 // Making your recipe immutable helps make them idempotent and eliminates categories of possible bugs.
 // Configuring your recipe in this way also guarantees that basic validation of parameters will be done for you by rewrite.
 // Also note: All recipes must be serializable. This is verified by RewriteTest.rewriteRun() in your tests.
 @Value
 @EqualsAndHashCode(callSuper = false)
 public class SayHelloRecipe extends Recipe {
-    @Option(displayName = "Fully Qualified Class Name",
-            description = "A fully qualified class name indicating which class to add a hello() method to.",
-            example = "com.yourorg.FooBar")
-    @NonNull
+    @Option(displayName = "Fully qualified class name",
+            description = "A fully qualified class name indicating which class to add a `hello()` method to.",
+            example = "`com.yourorg.FooBar`")
     String fullyQualifiedClassName;
 
-    // All recipes must be serializable. This is verified by RewriteTest.rewriteRun() in your tests.
-    @JsonCreator
-    public SayHelloRecipe(@NonNull @JsonProperty("fullyQualifiedClassName") String fullyQualifiedClassName) {
-        this.fullyQualifiedClassName = fullyQualifiedClassName;
-    }
-
     @Override
     public String getDisplayName() {
         return "Say Hello";
     }
 
     @Override
     public String getDescription() {
-        return "Adds a \"hello\" method to the specified class.";
+        return "Adds a `hello` method to the specified class.";
     }
 
     @Override
     public TreeVisitor<?, ExecutionContext> getVisitor() {
         // getVisitor() should always return a new instance of the visitor to avoid any state leaking between cycles
-        return new SayHelloVisitor();
-    }
-
-    public class SayHelloVisitor extends JavaIsoVisitor<ExecutionContext> {
-        private final JavaTemplate helloTemplate =
-                JavaTemplate.builder( "public String hello() { return \"Hello from #{}!\"; }")
-                        .build();
-
-        @Override
-        public J.ClassDeclaration visitClassDeclaration(J.ClassDeclaration classDecl, ExecutionContext executionContext) {
-            // Don't make changes to classes that don't match the fully qualified name
-            if (classDecl.getType() == null || !classDecl.getType().getFullyQualifiedName().equals(fullyQualifiedClassName)) {
-                return classDecl;
-            }
-
-            // Check if the class already has a method named "hello".
-            boolean helloMethodExists = classDecl.getBody().getStatements().stream()
-                    .filter(statement -> statement instanceof J.MethodDeclaration)
-                    .map(J.MethodDeclaration.class::cast)
-                    .anyMatch(methodDeclaration -> methodDeclaration.getName().getSimpleName().equals("hello"));
-
-            // If the class already has a `hello()` method, don't make any changes to it.
-            if (helloMethodExists) {
-                return classDecl;
+        return new JavaIsoVisitor<ExecutionContext>() {
+
+            @Override
+            public J.ClassDeclaration visitClassDeclaration(J.ClassDeclaration classDecl, ExecutionContext ctx) {
+                // Don't make changes to classes that don't match the fully qualified name
+                if (!TypeUtils.isOfClassType(classDecl.getType(), fullyQualifiedClassName)) {
+                    return classDecl;
+                }
+
+                // Check if the class already has a method named "hello".
+                boolean helloMethodExists = classDecl.getBody().getStatements().stream()
+                        .filter(J.MethodDeclaration.class::isInstance)
+                        .map(J.MethodDeclaration.class::cast)
+                        .map(J.MethodDeclaration::getSimpleName)
+                        .anyMatch("hello"::equals);
+
+                // If the class already has a `hello()` method, don't make any changes to it.
+                if (helloMethodExists) {
+                    return classDecl;
+                }
+
+                // insert the defined method into the existing class declaration
+                return JavaTemplate.apply(
+                        "public String hello() { return \"Hello from #{}!\"; }",
+                        updateCursor(classDecl),
+                        classDecl.getBody().getCoordinates().addMethodDeclaration(Comparator.comparing(J.MethodDeclaration::getSimpleName)),
+                        fullyQualifiedClassName);
             }
-
-            // Interpolate the fullyQualifiedClassName into the template and use the resulting LST to update the class body
-            classDecl = classDecl.withBody( helloTemplate.apply(new Cursor(getCursor(), classDecl.getBody()),
-                    classDecl.getBody().getCoordinates().lastStatement(),
-                    fullyQualifiedClassName ));
-
-            return classDecl;
-        }
+        };
     }
 }
 ```
@@ -549,31 +541,30 @@ public class SayHelloRecipe extends Recipe {
 ```java
 package com.yourorg;
 
-import com.fasterxml.jackson.annotation.JsonCreator;
-import com.fasterxml.jackson.annotation.JsonProperty;
-import lombok.Value;
 import org.jspecify.annotations.NonNull;
-import org.openrewrite.*;
+import org.openrewrite.ExecutionContext;
+import org.openrewrite.Option;
+import org.openrewrite.Recipe;
+import org.openrewrite.TreeVisitor;
 import org.openrewrite.java.JavaIsoVisitor;
 import org.openrewrite.java.JavaTemplate;
 import org.openrewrite.java.tree.J;
+import org.openrewrite.java.tree.TypeUtils;
 
+import java.util.Comparator;
 import java.util.Objects;
 
 // Making your recipe immutable helps make them idempotent and eliminates categories of possible bugs.
 // Configuring your recipe in this way also guarantees that basic validation of parameters will be done for you by rewrite.
 // Also note: All recipes must be serializable. This is verified by RewriteTest.rewriteRun() in your tests.
-@Value
-public class SayHelloRecipe extends Recipe {
-    @Option(displayName = "Fully Qualified Class Name",
-            description = "A fully qualified class name indicating which class to add a hello() method to.",
-            example = "com.yourorg.FooBar")
+public final class SayHelloRecipe extends Recipe {
+    @Option(displayName = "Fully qualified class name",
+            description = "A fully qualified class name indicating which class to add a `hello()` method to.",
+            example = "`com.yourorg.FooBar`")
     @NonNull
-    String fullyQualifiedClassName;
+    private final String fullyQualifiedClassName;
 
-    // All recipes must be serializable. This is verified by RewriteTest.rewriteRun() in your tests.
-    @JsonCreator
-    public SayHelloRecipe(@NonNull @JsonProperty("fullyQualifiedClassName") String fullyQualifiedClassName) {
+    public SayHelloRecipe(@NonNull String fullyQualifiedClassName) {
         this.fullyQualifiedClassName = fullyQualifiedClassName;
     }
 
@@ -584,13 +575,41 @@ public class SayHelloRecipe extends Recipe {
 
     @Override
     public String getDescription() {
-        return "Adds a \"hello\" method to the specified class.";
+        return "Adds a `hello` method to the specified class.";
     }
 
     @Override
     public TreeVisitor<?, ExecutionContext> getVisitor() {
         // getVisitor() should always return a new instance of the visitor to avoid any state leaking between cycles
-        return new SayHelloVisitor();
+        return new JavaIsoVisitor<ExecutionContext>() {
+
+            @Override
+            public J.ClassDeclaration visitClassDeclaration(J.ClassDeclaration classDecl, ExecutionContext ctx) {
+                // Don't make changes to classes that don't match the fully qualified name
+                if (!TypeUtils.isOfClassType(classDecl.getType(), fullyQualifiedClassName)) {
+                    return classDecl;
+                }
+
+                // Check if the class already has a method named "hello".
+                boolean helloMethodExists = classDecl.getBody().getStatements().stream()
+                        .filter(J.MethodDeclaration.class::isInstance)
+                        .map(J.MethodDeclaration.class::cast)
+                        .map(J.MethodDeclaration::getSimpleName)
+                        .anyMatch("hello"::equals);
+
+                // If the class already has a `hello()` method, don't make any changes to it.
+                if (helloMethodExists) {
+                    return classDecl;
+                }
+
+                // insert the defined method into the existing class declaration
+                return JavaTemplate.apply(
+                        "public String hello() { return \"Hello from #{}!\"; }",
+                        updateCursor(classDecl),
+                        classDecl.getBody().getCoordinates().addMethodDeclaration(Comparator.comparing(J.MethodDeclaration::getSimpleName)),
+                        fullyQualifiedClassName);
+            }
+        };
     }
 
     @Override
@@ -613,46 +632,6 @@ public class SayHelloRecipe extends Recipe {
     public int hashCode() {
         return Objects.hash(super.hashCode(), fullyQualifiedClassName);
     }
-
-    public String getFullyQualifiedClassName() {
-        return fullyQualifiedClassName;
-    }
-
-    public void setFullyQualifiedClassName(String fullyQualifiedClassName) {
-        this.fullyQualifiedClassName = fullyQualifiedClassName;
-    }
-
-    public class SayHelloVisitor extends JavaIsoVisitor<ExecutionContext> {
-        private final JavaTemplate helloTemplate =
-                JavaTemplate.builder( "public String hello() { return \"Hello from #{}!\"; }")
-                        .build();
-
-        @Override
-        public J.ClassDeclaration visitClassDeclaration(J.ClassDeclaration classDecl, ExecutionContext executionContext) {
-            // Don't make changes to classes that don't match the fully qualified name
-            if (classDecl.getType() == null || !classDecl.getType().getFullyQualifiedName().equals(fullyQualifiedClassName)) {
-                return classDecl;
-            }
-
-            // Check if the class already has a method named "hello".
-            boolean helloMethodExists = classDecl.getBody().getStatements().stream()
-                    .filter(statement -> statement instanceof J.MethodDeclaration)
-                    .map(J.MethodDeclaration.class::cast)
-                    .anyMatch(methodDeclaration -> methodDeclaration.getName().getSimpleName().equals("hello"));
-
-            // If the class already has a `hello()` method, don't make any changes to it.
-            if (helloMethodExists) {
-                return classDecl;
-            }
-
-            // Interpolate the fullyQualifiedClassName into the template and use the resulting LST to update the class body
-            classDecl = classDecl.withBody( helloTemplate.apply(new Cursor(getCursor(), classDecl.getBody()),
-                    classDecl.getBody().getCoordinates().lastStatement(),
-                    fullyQualifiedClassName ));
-
-            return classDecl;
-        }
-    }
 }
 ```
 </TabItem>