Merge branch 'add-jakarta-support' into 'main'

Generate jakarta servlets

See merge request weblogic-cloud/weblogic-monitoring-exporter!300

Author: rjeberhard

build-helper-mojo/pom.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
-    Copyright (c) 2019, 2024, Oracle and/or its affiliates.
+    Copyright (c) 2019, 2025, Oracle and/or its affiliates.
     Licensed under the Universal Permissive License v 1.0 as shown at https://oss.oracle.com/licenses/upl.
 -->
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
@@ -17,13 +17,29 @@
 
     <name>Exporter Build Helper Maven Mojo</name>
 
+    <properties>
+        <maven.compiler.release>17</maven.compiler.release>
+    </properties>
+
     <dependencies>
         <dependency>
             <groupId>org.apache.maven</groupId>
             <artifactId>maven-plugin-api</artifactId>
             <version>3.9.9</version>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>org.apache.maven</groupId>
+            <artifactId>maven-core</artifactId>
+            <version>3.9.9</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.maven</groupId>
+            <artifactId>maven-artifact</artifactId>
+            <version>3.9.9</version>
+            <scope>provided</scope>
+        </dependency>
         <dependency>
             <groupId>org.apache.maven</groupId>
             <artifactId>maven-model</artifactId>

build-helper-mojo/src/main/java/com/oracle/wls/buildhelper/JavaxToJakartaMojo.java

@@ -0,0 +1,146 @@
+// Copyright (c) 2025, Oracle and/or its affiliates.
+// Licensed under the Universal Permissive License v 1.0 as shown at https://oss.oracle.com/licenses/upl.
+
+package com.oracle.wls.buildhelper;
+
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.LifecyclePhase;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.MavenProject;
+
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Function;
+import java.util.stream.Stream;
+
+/**
+ * Supports generation of web applications that work on both javax-dependent and jakarta-dependent WebLogic Server
+ * instances. It depends on several things:
+ * 1. The Exporter web application uses annotations rather than an XML file to configure its servlets,
+ * 2. WebLogic will ignore servlets whose dependencies it cannot load
+ * 3. Common code in this application does not depend on classes that depend on the EE version.
+ * <br/>
+ * The plugin will look for source files that reference javax.servlet; it will report a failure if any such
+ * files are in packages whose last element is not "javax." It will then generate corresponding source files
+ * that reference the corresponding jakarta.servlet classes and place them in a package with "jakarta" instead
+ * of "javax" in a separate directory, and add the directory to the compiler source roots.
+ */
+@Mojo(name = "transform", defaultPhase = LifecyclePhase.GENERATE_SOURCES)
+public class JavaxToJakartaMojo extends AbstractMojo {
+  /**
+   * The source directories containing the sources to be processed.
+   */
+  @Parameter(defaultValue = "${project.compileSourceRoots}", required = true)
+  List<String> compileSourceRoots;
+
+  /**
+   * Specify where to place generated jakarta-based files created by this mojo.
+   */
+  @Parameter(defaultValue = "${project.build.directory}/generated-sources/jakarta")
+  File generatedSourcesDirectory;
+
+  /**
+   * The project used as an interface to Maven internals.
+   */
+  @Parameter(defaultValue = "${project}", readonly = true)
+  MavenProject project;
+
+  static Function<String, Path> toPath = Path::of;
+
+
+  @Override
+  public void execute() throws MojoExecutionException, MojoFailureException {
+    project.addCompileSourceRoot(generatedSourcesDirectory.getPath());
+
+    try {
+      getFilesToTransform().forEach(this::transformFile);
+    } catch (RuntimeException e) {
+      throw new MojoExecutionException(e);
+    }
+  }
+
+  private void transformFile(Path inputFile) {
+    Path outputFile = getOutputFile(inputFile);
+    try {
+      Files.createDirectories(outputFile.getParent());
+      transformFile(inputFile, outputFile);
+    } catch (IOException e) {
+      throw new RuntimeException("Unable to transform files", e);
+    }
+  }
+
+  private static void transformFile(Path inputFile, Path outputFile) throws IOException {
+    try (BufferedWriter bufferedWriter = Files.newBufferedWriter(outputFile);
+         Stream<String> lines = Files.lines(inputFile)) {
+      lines.forEach(l -> transformLine(l, bufferedWriter));
+    }
+  }
+
+  private static void transformLine(String line, BufferedWriter bufferedWriter) {
+    try {
+      bufferedWriter.write(line.replaceAll("javax", "jakarta"));
+      bufferedWriter.newLine();
+    } catch (IOException e) {
+      throw new RuntimeException(e.getMessage(), e);
+    }
+  }
+
+  private Path getGeneratedSourceRoot() {
+    return toPath.apply(generatedSourcesDirectory.getPath());
+  }
+
+  Stream<Path> getFilesToTransform() throws MojoFailureException {
+    final List<Path> selectedFiles = new ArrayList<>();
+
+    try (Stream<Path> files = Files.walk(getCompileSourceRoot())) {
+      files.filter(Files::isRegularFile).filter(this::containsTransformedJavaxPackage).forEach(selectedFiles::add);
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
+
+    verifySelectedFilesHaveJavaxPackage(selectedFiles);
+    return selectedFiles.stream();
+  }
+
+  private void verifySelectedFilesHaveJavaxPackage(List<Path> selectedFiles) throws MojoFailureException {
+    List<String> badPaths = selectedFiles.stream().filter(this::lacksJavaxFinalPackage).map(Path::toString).toList();
+
+    if (!badPaths.isEmpty())
+      throw new MojoFailureException("Cannot do transformation. The following classes reference javax.servlet packages " +
+            "but are not in a package name ending in .javax: " + String.join(", ", badPaths));
+  }
+
+  private boolean lacksJavaxFinalPackage(Path path) {
+    return !path.getParent().endsWith("javax");
+  }
+
+  private Path toRelativePath(Path p) {
+    return getCompileSourceRoot().relativize(p);
+  }
+
+  private Path getCompileSourceRoot() {
+    return toPath.apply(compileSourceRoots.get(0));
+  }
+
+  private boolean containsTransformedJavaxPackage(Path path) {
+    try {
+      return Files.readAllLines(path).stream().anyMatch(s -> s.contains("javax.servlet"));
+    } catch (IOException e) {
+      return false;
+    }
+  }
+
+  public Path getOutputFile(Path inputPath) {
+    final Path fileName = inputPath.getFileName();
+    final Path relativePath = toRelativePath(inputPath).getParent().getParent().resolve("jakarta");
+    return getGeneratedSourceRoot().resolve(relativePath).resolve(fileName);
+  }
+}