Make it a Javac plugin (#41)

.github/workflows/ci.yml

@@ -17,6 +17,6 @@ jobs:
     - name: Set up JDK
       uses: actions/setup-java@v1
       with:
-        java-version: 13
+        java-version: 14
     - name: Build with Gradle
       run: ./gradlew build

.gitignore

@@ -3,9 +3,13 @@
 .gradle
 
 build/
+target/
 
 .idea/
 out/
+*.iml
+*.ipr
+*.iws
 
 
 .project

README.md

@@ -1,4 +1,4 @@
-# Jabel - use Javac 12+ syntax when targeting Java 8
+# Jabel - use modern Java 9-14 syntax when targeting Java 8
 
 > Because life is too short to wait for your users to upgrade their Java!
 
@@ -13,7 +13,7 @@ But, since most of features after Java 8 did not require a change in the bytecod
 
 ## How Jabel works
 
-Although Jabel is an annotation processor, it does not run any processing,
+Although Jabel is a javac compiler plugin, it does not run any processing,
 but instruments the java compiler classes and makes it treat some new Java 9+ languages features
 as they were supported in Java 8.
 
@@ -32,7 +32,7 @@ require the same target as the JVM because they get released altogether.
 As was previously described, Jabel makes the compiler think that certain features were developed
 for Java 8, and removes the checks that otherwise will report them as invalid for the target.
 
-It is important to understand that it will use the same code as for Java 12 and won't change
+It is important to understand that it will use the same desugaring code as for Java 9+ but won't change
 the result's classfile version, because the compilation phase will be done with Java 8 target.
 
 ## How to use
@@ -66,7 +66,7 @@ Jabel has to be added as an annotation processor to your maven-compiler-plugin:
                         <groupId>org.apache.maven.plugins</groupId>
                         <artifactId>maven-compiler-plugin</artifactId>
                         <configuration>
-                            <release>13</release>
+                            <release>14</release>
                             <compilerArgs>
                                 <arg>--enable-preview</arg>
                             </compilerArgs>
@@ -77,29 +77,33 @@ Jabel has to be added as an annotation processor to your maven-compiler-plugin:
         </profile>
     </profiles>
 
-<build>
-    <plugins>
-        <plugin>
-            <groupId>org.apache.maven.plugins</groupId>
-            <artifactId>maven-compiler-plugin</artifactId>
-            <version>3.8.1</version>
-            <configuration>
-                <!-- Make sure we're not using Java 9+ APIs -->
-                <release>8</release>
-                <annotationProcessorPaths>
-                    <annotationProcessorPath>
-                        <groupId>com.github.bsideup.jabel</groupId>
-                        <artifactId>jabel-javac-plugin</artifactId>
-                        <version>0.2.0</version>
-                    </annotationProcessorPath>
-                </annotationProcessorPaths>
-                <annotationProcessors>
-                    <annotationProcessor>com.github.bsideup.jabel.JabelJavacProcessor</annotationProcessor>
-                </annotationProcessors>
-            </configuration>
-        </plugin>
-    </plugins>
-</build>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.8.1</version>
+                <configuration>
+                    <!-- Make sure we're not using Java 9+ APIs -->
+                    <release>8</release>
+                    <source>14</source>
+                    <target>14</target>
+                    <compilerArgs>
+                        <arg>-Xplugin:jabel</arg>
+                    </compilerArgs>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.github.bsideup.jabel</groupId>
+            <artifactId>jabel-javac-plugin</artifactId>
+            <version>0.3.0</version>
+            <scope>provided</scope>
+        </dependency>
+    </dependencies>
 ```
 
 Compile your project and verify that Jabel is installed and successfully reports:
@@ -129,19 +133,26 @@ repositories {
 Then, add Jabel as any other annotation processor:
 ```groovy
 dependencies {
-    annotationProcessor 'com.github.bsideup.jabel:jabel-javac-plugin:0.2.0'
+    annotationProcessor 'com.github.bsideup.jabel:jabel-javac-plugin:0.3.0'
 }
 ```
 
 Now, even if you set source/target/release to 8, the compiler will let you use some new language features.
 The full list of features will be printed during the compilation.
 ```groovy
-sourceCompatibility = 12 // for the IDE support
+sourceCompatibility = 14 // for the IDE support
 
-compileJava {
+tasks.withType(JavaCompile).all {
     options.compilerArgs = [
-            "--release", "8" // Avoid using Java 12 APIs
+            "--release", "8", // Avoid using Java 9+ APIs
+            '--enable-preview',
     ]
+
+    doFirst {
+        options.compilerArgs = options.compilerArgs.findAll {
+            it != '--enable-preview'
+        }
+    }
 }
 ```
 

example/build.gradle

@@ -2,19 +2,20 @@ plugins {
     id "java"
 }
 
-sourceCompatibility = 13
+sourceCompatibility = 14
 targetCompatibility = 8
 
-compileJava {
+tasks.withType(JavaCompile).all {
     options.compilerArgs = [
             "--release", "8",
+            '--enable-preview',
     ]
-}
 
-compileTestJava {
-    options.compilerArgs = [
-            "--release", "8",
-    ]
+    doFirst {
+        options.compilerArgs = options.compilerArgs.findAll {
+            it != '--enable-preview'
+        }
+    }
 }
 
 test {

example/src/main/java/com/example/JabelExample.java

@@ -15,7 +15,10 @@ public String run(String[] args) {
         // https://openjdk.java.net/jeps/325
         var result = switch (args.length) {
             case 1 -> {
-                yield "one";
+                yield """
+                        one...
+                        yet pretty long!
+                """;
             }
             case 2, 3 -> "two or three";
             default -> new JabelExample().new Inner().innerPublic();
@@ -33,8 +36,14 @@ private String outerPrivate(List<String>... args) {
             @Override
             public String call() {
                 // Var in lambda parameter
-                Function<String, String> function = (var prefix) -> {
-                    return prefix + Integer.toString(0);
+                Function<Object, String> function = (var prefix) -> {
+                    // Pattern Matching in instanceof
+                    // https://openjdk.java.net/jeps/305
+                    if (prefix instanceof String s) {
+                        return s + Integer.toString(0);
+                    } else {
+                        throw new IllegalArgumentException("Expected string!");
+                    }
                 };
                 // Test indy strings
                 return function.apply("idk ");

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.2.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.5.1-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

gradlew

@@ -7,7 +7,7 @@
 # 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
+#      https://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,
@@ -125,8 +125,8 @@ if $darwin; then
     GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
 fi
 
-# For Cygwin, switch paths to Windows format before running java
-if $cygwin ; then
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
     APP_HOME=`cygpath --path --mixed "$APP_HOME"`
     CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
     JAVACMD=`cygpath --unix "$JAVACMD"`
@@ -154,19 +154,19 @@ if $cygwin ; then
         else
             eval `echo args$i`="\"$arg\""
         fi
-        i=$((i+1))
+        i=`expr $i + 1`
     done
     case $i in
-        (0) set -- ;;
-        (1) set -- "$args0" ;;
-        (2) set -- "$args0" "$args1" ;;
-        (3) set -- "$args0" "$args1" "$args2" ;;
-        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
-        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
-        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
-        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
-        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
-        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
     esac
 fi
 
@@ -175,14 +175,9 @@ save () {
     for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
     echo " "
 }
-APP_ARGS=$(save "$@")
+APP_ARGS=`save "$@"`
 
 # Collect all arguments for the java command, following the shell quoting and substitution rules
 eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
 
-# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
-if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
-  cd "$(dirname "$0")"
-fi
-
 exec "$JAVACMD" "$@"

gradlew.bat

@@ -5,7 +5,7 @@
 @rem you may not use this file except in compliance with the License.
 @rem You may obtain a copy of the License at
 @rem
-@rem      http://www.apache.org/licenses/LICENSE-2.0
+@rem      https://www.apache.org/licenses/LICENSE-2.0
 @rem
 @rem Unless required by applicable law or agreed to in writing, software
 @rem distributed under the License is distributed on an "AS IS" BASIS,
@@ -29,6 +29,9 @@ if "%DIRNAME%" == "" set DIRNAME=.
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
 set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 

jabel-javac-plugin/build.gradle

@@ -6,6 +6,6 @@ plugins {
 sourceCompatibility = targetCompatibility = 8
 
 dependencies {
-    compile 'net.bytebuddy:byte-buddy:1.10.8'
-    compile 'net.bytebuddy:byte-buddy-agent:1.10.8'
+    compile 'net.bytebuddy:byte-buddy:1.10.14'
+    compile 'net.bytebuddy:byte-buddy-agent:1.10.14'
 }

jabel-javac-plugin/src/main/java/com/github/bsideup/jabel/JabelJavacProcessor.java → jabel-javac-plugin/src/main/java/com/github/bsideup/jabel/JabelCompilerPlugin.java

@@ -1,5 +1,7 @@
 package com.github.bsideup.jabel;
 
+import com.sun.source.util.JavacTask;
+import com.sun.source.util.Plugin;
 import com.sun.tools.javac.code.Source;
 import com.sun.tools.javac.parser.JavaTokenizer;
 import com.sun.tools.javac.parser.JavacParser;
@@ -8,29 +10,19 @@
 import net.bytebuddy.asm.Advice;
 import net.bytebuddy.dynamic.loading.ClassReloadingStrategy;
 
-import javax.annotation.processing.Completion;
-import javax.annotation.processing.ProcessingEnvironment;
-import javax.annotation.processing.Processor;
-import javax.annotation.processing.RoundEnvironment;
-import javax.lang.model.SourceVersion;
-import javax.lang.model.element.AnnotationMirror;
-import javax.lang.model.element.Element;
-import javax.lang.model.element.ExecutableElement;
-import javax.lang.model.element.TypeElement;
 import java.lang.reflect.Field;
 import java.util.Arrays;
 import java.util.Objects;
 import java.util.Set;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
-import static java.util.Collections.emptySet;
 import static net.bytebuddy.matcher.ElementMatchers.named;
 import static net.bytebuddy.matcher.ElementMatchers.takesArguments;
 
-public class JabelJavacProcessor implements Processor {
+public class JabelCompilerPlugin implements Plugin {
 
-    private static final Set<Source.Feature> ENABLED_FEATURES = Stream
+    static final Set<Source.Feature> ENABLED_FEATURES = Stream
             .of(
                     "PRIVATE_SAFE_VARARGS",
 
@@ -60,7 +52,8 @@ public class JabelJavacProcessor implements Processor {
             .filter(Objects::nonNull)
             .collect(Collectors.toSet());
 
-    static {
+    @Override
+    public void init(JavacTask task, String... args) {
         ByteBuddyAgent.install();
 
         ByteBuddy byteBuddy = new ByteBuddy();
@@ -89,15 +82,7 @@ public class JabelJavacProcessor implements Processor {
         } catch (Exception e) {
             throw new RuntimeException(e);
         }
-    }
 
-    @Override
-    public SourceVersion getSupportedSourceVersion() {
-        return SourceVersion.RELEASE_8;
-    }
-
-    @Override
-    public void init(ProcessingEnvironment processingEnv) {
         System.out.println(
                 ENABLED_FEATURES.stream()
                         .map(Enum::name)
@@ -110,22 +95,12 @@ public void init(ProcessingEnvironment processingEnv) {
     }
 
     @Override
-    public Set<String> getSupportedOptions() {
-        return emptySet();
+    public String getName() {
+        return "jabel";
     }
 
-    @Override
-    public Set<String> getSupportedAnnotationTypes() {
-        return emptySet();
-    }
-
-    @Override
-    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
-        return false;
-    }
-
-    @Override
-    public Iterable<? extends Completion> getCompletions(Element element, AnnotationMirror annotation, ExecutableElement member, String userText) {
-        return emptySet();
+    // Make it auto start on Java 14+
+    public boolean autoStart() {
+        return true;
     }
 }

jabel-javac-plugin/src/main/resources/META-INF/services/com.sun.source.util.Plugin

@@ -0,0 +1 @@
+com.github.bsideup.jabel.JabelCompilerPlugin