GROOVY-7423: Access to Method parameter names at runtime.

src/main/groovy/ui/GroovyMain.java

@@ -194,6 +194,7 @@ private static Options buildOptions() {
                 .addOption(builder("i").argName("extension").optionalArg(true).desc("modify files in place; create backup if extension is given (e.g. \'.bak\')").build())
                 .addOption(builder("n").hasArg(false).desc("process files line by line using implicit 'line' variable").build())
                 .addOption(builder("p").hasArg(false).desc("process files line by line and print result (see also -n)").build())
+                .addOption(builder("pa").hasArg(false).desc("Generate metadata for reflection on method parameter names (jdk8+ only)").longOpt("parameters").build())
                 .addOption(builder("l").argName("port").optionalArg(true).desc("listen on a port and process inbound lines (default: 1960)").build())
                 .addOption(builder("a").argName("splitPattern").optionalArg(true).desc("split lines using splitPattern (default '\\s') using implicit 'split' variable").longOpt("autosplit").build())
                 .addOption(builder().longOpt("indy").desc("enables compilation using invokedynamic").build())
@@ -245,6 +246,7 @@ private static boolean process(CommandLine line) throws ParseException, IOExcept
         main.isScriptFile = !line.hasOption('e');
         main.debug = line.hasOption('d');
         main.conf.setDebug(main.debug);
+        main.conf.setParameters(line.hasOption("pa"));
         main.processFiles = line.hasOption('p') || line.hasOption('n');
         main.autoOutput = line.hasOption('p');
         main.editFiles = line.hasOption('i');

src/main/org/codehaus/groovy/classgen/AsmClassGenerator.java

@@ -374,6 +374,14 @@ protected void visitConstructorOrMethod(MethodNode node, boolean isConstructor)
             visitParameterAnnotations(parameters[i], i, mv);
         }
 
+        // Add parameter names to the MethodVisitor (jdk8+ only)
+        if (getCompileUnit().getConfig().getParameters()) {
+            for (int i = 0; i < parameters.length; i++) {
+                // TODO handle ACC_SYNTHETIC for enum method parameters?
+                mv.visitParameter(parameters[i].getName(), 0);
+            }
+        }
+
         if (controller.getClassNode().isAnnotationDefinition() && !node.isStaticConstructor()) {
             visitAnnotationDefault(node, mv);
         } else if (!node.isAbstract()) {

src/main/org/codehaus/groovy/control/CompilerConfiguration.java

@@ -108,6 +108,11 @@ public class CompilerConfiguration {
      */
     private boolean debug;
 
+    /**
+     * If true, generates metadata for reflection on method parameters
+     */
+    private boolean parameters = false;
+
     /**
      * The number of non-fatal errors to allow before bailing
      */
@@ -179,10 +184,12 @@ public CompilerConfiguration() {
         setClasspath("");
         setVerbose(false);
         setDebug(false);
+        setParameters(safeGetSystemProperty("groovy.parameters") != null);
         setTolerance(10);
         setScriptBaseClass(null);
         setRecompileGroovySource(false);
         setMinimumRecompilationInterval(100);
+        // TODO change following try/catches to use #safeGetSystemProperty(...) ??
         // Target bytecode
         String targetByteCode = null;
         try {
@@ -253,6 +260,45 @@ public CompilerConfiguration() {
         setOptimizationOptions(options);
     }
 
+    /**
+     * Retrieves a System property, or null if any of the following exceptions occur.
+     * <ul>
+     *     <li>SecurityException - if a security manager exists and its checkPropertyAccess method doesn't allow access to the specified system property.</li>
+     *     <li>NullPointerException - if key is null.</li>
+     *     <li>IllegalArgumentException - if key is empty.</li>
+     * </ul>
+     * @param key the name of the system property.
+     * @return
+     */
+    private String safeGetSystemProperty(String key){
+        return safeGetSystemProperty(key, null);
+    }
+
+    /**
+     * Retrieves a System property, or null if any of the following exceptions occur (Warning: Exception messages are
+     * suppressed).
+     * <ul>
+     *     <li>SecurityException - if a security manager exists and its checkPropertyAccess method doesn't allow access to the specified system property.</li>
+     *     <li>NullPointerException - if key is null.</li>
+     *     <li>IllegalArgumentException - if key is empty.</li>
+     * </ul>
+     * @param key the name of the system property.
+     * @param def a default value.
+     * @return
+     */
+    private String safeGetSystemProperty(String key, String def){
+        try {
+            return System.getProperty(key, def);
+        } catch (SecurityException t){
+            // suppress exception
+        } catch (NullPointerException t){
+            // suppress exception
+        } catch (IllegalArgumentException t){
+            // suppress exception
+        }
+        return def;
+    }
+
     /**
      * Copy constructor.  Use this if you have a mostly correct configuration
      * for your compilation but you want to make a some changes programatically.
@@ -276,6 +322,7 @@ public CompilerConfiguration(CompilerConfiguration configuration) {
         setClasspathList(new LinkedList<String>(configuration.getClasspath()));
         setVerbose(configuration.getVerbose());
         setDebug(configuration.getDebug());
+        setParameters(configuration.getParameters());
         setTolerance(configuration.getTolerance());
         setScriptBaseClass(configuration.getScriptBaseClass());
         setRecompileGroovySource(configuration.getRecompileGroovySource());
@@ -450,6 +497,11 @@ else if (text.startsWith("paranoia")) {
         text = configuration.getProperty("groovy.output.debug");
         if (text != null && text.equalsIgnoreCase("true")) setDebug(true);
 
+        //
+        // Parameters
+        //
+        setParameters(configuration.getProperty("groovy.parameters") != null);
+
         //
         // Tolerance
         // 
@@ -625,13 +677,27 @@ public boolean getDebug() {
         return this.debug;
     }
 
+    /**
+     * Returns true if parameter metadata generation has been enabled.
+     */
+    public boolean getParameters() {
+        return this.parameters;
+    }
+
     /**
      * Turns debugging operation on or off.
      */
     public void setDebug(boolean debug) {
         this.debug = debug;
     }
 
+    /**
+     * Turns parameter metadata generation on or off.
+     */
+    public void setParameters(boolean parameters) {
+        this.parameters = parameters;
+    }
+
     /**
      * Returns the requested error tolerance.
      */

src/main/org/codehaus/groovy/tools/FileSystemCompiler.java

@@ -45,6 +45,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Arrays;
 
 /**
  * Command-line compiler (aka. <tt>groovyc</tt>).
@@ -275,6 +276,8 @@ public static CompilerConfiguration generateCompilerConfigurationFromOptions(Com
             configuration.setTargetDirectory(cli.getOptionValue('d'));
         }
 
+        configuration.setParameters(cli.hasOption("pa"));
+
         if (cli.hasOption("encoding")) {
             configuration.setSourceEncoding(cli.getOptionValue("encoding"));
         }
@@ -287,11 +290,18 @@ public static CompilerConfiguration generateCompilerConfigurationFromOptions(Com
         if (cli.hasOption('j')) {
             Map<String, Object> compilerOptions = new HashMap<String, Object>();
 
-            String[] opts = cli.getOptionValues("J");
-            compilerOptions.put("namedValues", opts);
+            String[] namedValues = cli.getOptionValues("J");
+            compilerOptions.put("namedValues", namedValues);
 
-            opts = cli.getOptionValues("F");
-            compilerOptions.put("flags", opts);
+            String[] flags = cli.getOptionValues("F");
+            if (flags != null && cli.hasOption("pa")){
+                // convert to a list, so we can add a parameter...
+                List<String> tmp = new ArrayList<String>(Arrays.asList(flags));
+                tmp.add("parameters");
+                // convert back to an array...
+                flags = tmp.toArray(new String[tmp.size()]);
+            }
+            compilerOptions.put("flags", flags);
 
             configuration.setJointCompilationOptions(compilerOptions);
         }
@@ -336,6 +346,7 @@ public static Options createCompilationOptions() {
         options.addOption(Option.builder("h").longOpt("help").desc("Print a synopsis of standard options").build());
         options.addOption(Option.builder("v").longOpt("version").desc("Print the version").build());
         options.addOption(Option.builder("e").longOpt("exception").desc("Print stack trace on error").build());
+        options.addOption(Option.builder("pa").longOpt("parameters").desc("Generate metadata for reflection on method parameter names (jdk8+ only)").build());
         options.addOption(Option.builder("j").longOpt("jointCompilation").desc("Attach javac compiler to compile .java files").build());
         options.addOption(Option.builder("b").longOpt("basescript").hasArg().argName("class").desc("Base class name for scripts (must derive from Script)").build());
 

src/spec/doc/tools-groovy.adoc

@@ -46,4 +46,5 @@ int (disable any int based optimizations) |
 | -n | | process files line by line using implicit 'line' variable |
 | -p | | process files line by line and print result (see also -n) |
 | -v | --version | display the Groovy and JVM versions | groovy -v
+| -pa | --parameters | Generates metadata for reflection on method parameter names on JDK 8 and above. Defaults to false. | groovy --parameters Person.groovy
 |=======================================================================

src/spec/doc/tools-groovyc.adoc

@@ -38,6 +38,7 @@ argument. | groovyc -cp lib/dep.jar MyClass.groovy
 | | --configscript | Advanced compiler configuration script | groovyc --configscript config/config.groovy src/Person.groovy
 | -Jproperty=value | | Properties to be passed to `javac` if joint compilation is enabled | groovyc -j -Jtarget=1.5 -Jsource=1.5 A.groovy B.java
 | -Fflag | | Flags to be passed to `javac` if joint compilation is enabled | groovyc -j -Fnowarn A.groovy B.java
+| -pa | --parameters | Generates metadata for reflection on method parameter names on JDK 8 and above. Defaults to false. | groovyc --parameters Person.groovy
 |=======================================================================
 
 *Notes:*
@@ -144,6 +145,8 @@ you need to set this flag to true. Defaults to false. |No
 
 |configscript |Set the configuration file used to customize the compilation configuration. |No
 
+|parameters |Generates metadata for reflection on method parameter names on JDK 8 and above. Defaults to false. |No
+
 |=======================================================================
 
 *Example:*

src/test/org/codehaus/groovy/control/CompilerConfigurationTest.java

@@ -122,6 +122,7 @@ public void testCopyConstructor1() {
 
         init.setWarningLevel(WarningMessage.POSSIBLE_ERRORS);
         init.setDebug(true);
+        init.setParameters(true);
         init.setVerbose(false);
         init.setTolerance(720);
         init.setMinimumRecompilationInterval(234);
@@ -147,6 +148,7 @@ public void testCopyConstructor1() {
 
         assertEquals(WarningMessage.POSSIBLE_ERRORS, init.getWarningLevel());
         assertEquals(true, init.getDebug());
+        assertEquals(true, init.getParameters());
         assertEquals(false, init.getVerbose());
         assertEquals(720, init.getTolerance());
         assertEquals(234, init.getMinimumRecompilationInterval());
@@ -194,6 +196,7 @@ public void testCopyConstructor2() {
 
         init.setWarningLevel(WarningMessage.POSSIBLE_ERRORS);
         init.setDebug(false);
+        init.setParameters(false);
         init.setVerbose(true);
         init.setTolerance(55);
         init.setMinimumRecompilationInterval(975);
@@ -211,6 +214,7 @@ public void testCopyConstructor2() {
 
         assertEquals(WarningMessage.POSSIBLE_ERRORS, init.getWarningLevel());
         assertEquals(false, init.getDebug());
+        assertEquals(false, init.getParameters());
         assertEquals(true, init.getVerbose());
         assertEquals(55, init.getTolerance());
         assertEquals(975, init.getMinimumRecompilationInterval());

subprojects/groovy-ant/src/main/java/org/codehaus/groovy/ant/Groovy.java

@@ -267,6 +267,22 @@ public void setScriptBaseClass(final String scriptBaseClass) {
         this.scriptBaseClass = scriptBaseClass;
     }
 
+    /**
+     * If true, generates metadata for reflection on method parameter names (jdk8+ only).  Defaults to false.
+     *
+     * @param parameters set to true to generate metadata.
+     */
+    public void setParameters(boolean parameters) {
+        configuration.setParameters(parameters);
+    }
+
+    /**
+     * Returns true if parameter metadata generation has been enabled.
+     */
+    public boolean getParameters() {
+        return configuration.getParameters();
+    }
+
     /**
      * Load the file and then execute it
      */

subprojects/groovy-ant/src/main/java/org/codehaus/groovy/ant/Groovyc.java

@@ -117,6 +117,7 @@
  * <li>keepStubs</li>
  * <li>forceLookupUnnamedFiles</li>
  * <li>configscript</li>
+ * <li>parameters</li>
  * </ul>
  * And these nested tasks:
  * <ul>
@@ -215,6 +216,12 @@ public class Groovyc extends MatchingTask {
 
     private Set<String> scriptExtensions = new LinkedHashSet<String>();
 
+
+    /**
+     * If true, generates metadata for reflection on method parameter names (jdk8+ only).  Defaults to false.
+     */
+    private boolean parameters = false;
+
     /**
      * Adds a path for source compilation.
      *
@@ -803,6 +810,22 @@ public boolean getForceLookupUnnamedFiles() {
         return forceLookupUnnamedFiles;
     }
 
+    /**
+     * If true, generates metadata for reflection on method parameter names (jdk8+ only).  Defaults to false.
+     *
+     * @param parameters set to true to generate metadata.
+     */
+    public void setParameters(boolean parameters) {
+        this.parameters = parameters;
+    }
+
+    /**
+     * Returns true if parameter metadata generation has been enabled.
+     */
+    public boolean getParameters() {
+        return this.parameters;
+    }
+
     /**
      * Executes the task.
      *
@@ -1034,6 +1057,13 @@ private void doForkCommandLineList(List<String> commandLineList, Path classpath,
         }
     }
 
+    /**
+     * Add "groovyc" parameters to the commandLineList, based on the ant configuration.
+     *
+     * @param commandLineList
+     * @param jointOptions
+     * @param classpath
+     */
     private void doNormalCommandLineList(List<String> commandLineList, List<String> jointOptions, Path classpath) {
         commandLineList.add("--classpath");
         commandLineList.add(classpath.toString());
@@ -1052,6 +1082,9 @@ private void doNormalCommandLineList(List<String> commandLineList, List<String>
         if (stacktrace) {
             commandLineList.add("-e");
         }
+        if (parameters) {
+            commandLineList.add("--parameters");
+        }
         if (useIndy) {
             commandLineList.add("--indy");
         }

subprojects/groovy-ant/src/spec/doc/groovy-ant-task.adoc

@@ -35,6 +35,7 @@ Assuming `groovy-all-VERSION.jar` is in `my.classpath` you will need to declare
 |fork|If enabled the script will be executed in another JVM (disabled by default).|No
 |scriptBaseClass|The name of the base class for scripts.|No
 |indy|If enabled the script will be executed with `invokedynamic` (disabled by default).|No
+|parameters |Generates metadata for reflection on method parameter names on JDK 8 and above. Defaults to false. |No
 |============================================
 
 == Parameters specified as nested elements