changeset 962:8f0dcb9499db

7021650: fix Context issues Reviewed-by: mcimadamore
author jjg
date Fri, 25 Feb 2011 12:09:33 -0800
parents 3e30c95da3c6
children 23b64ad3eec8
files src/share/classes/com/sun/tools/apt/util/Bark.java src/share/classes/com/sun/tools/javac/api/JavacTool.java src/share/classes/com/sun/tools/javac/file/CacheFSInfo.java src/share/classes/com/sun/tools/javac/file/JavacFileManager.java src/share/classes/com/sun/tools/javac/main/JavaCompiler.java src/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java src/share/classes/com/sun/tools/javac/util/Context.java src/share/classes/com/sun/tools/javadoc/JavadocClassReader.java src/share/classes/com/sun/tools/javadoc/JavadocEnter.java src/share/classes/com/sun/tools/javadoc/JavadocMemberEnter.java src/share/classes/com/sun/tools/javadoc/JavadocTodo.java src/share/classes/com/sun/tools/javadoc/Messager.java test/tools/javac/diags/ArgTypeCompilerFactory.java test/tools/javac/diags/Example.java test/tools/javac/util/context/T7021650.java
diffstat 15 files changed, 310 insertions(+), 65 deletions(-) [+]
line wrap: on
line diff
--- a/src/share/classes/com/sun/tools/apt/util/Bark.java	Thu Feb 24 08:40:49 2011 -0800
+++ b/src/share/classes/com/sun/tools/apt/util/Bark.java	Fri Feb 25 12:09:33 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2008, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2011, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,15 +48,15 @@
      * Preregisters factories to create and use a Bark object for use as
      * both a Log and a Bark.
      */
-    public static void preRegister(final Context context) {
+    public static void preRegister(Context context) {
         context.put(barkKey, new Context.Factory<Bark>() {
-            public Bark make() {
-                return new Bark(context);
+            public Bark make(Context c) {
+                return new Bark(c);
             }
         });
         context.put(Log.logKey, new Context.Factory<Log>() {
-            public Log make() {
-                return Bark.instance(context);
+            public Log make(Context c) {
+                return Bark.instance(c);
             }
         });
     }
--- a/src/share/classes/com/sun/tools/javac/api/JavacTool.java	Thu Feb 24 08:40:49 2011 -0800
+++ b/src/share/classes/com/sun/tools/javac/api/JavacTool.java	Fri Feb 25 12:09:33 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2011, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -157,19 +157,19 @@
     /**
      * Register that a compilation is about to start.
      */
-    void beginContext(final Context context) {
+    void beginContext(Context context) {
         if (compilationInProgress)
             throw new IllegalStateException("Compilation in progress");
         compilationInProgress = true;
         final JavaFileManager givenFileManager = context.get(JavaFileManager.class);
         context.put(JavaFileManager.class, (JavaFileManager)null);
         context.put(JavaFileManager.class, new Context.Factory<JavaFileManager>() {
-            public JavaFileManager make() {
+            public JavaFileManager make(Context c) {
                 if (givenFileManager != null) {
-                    context.put(JavaFileManager.class, givenFileManager);
+                    c.put(JavaFileManager.class, givenFileManager);
                     return givenFileManager;
                 } else {
-                    return new JavacFileManager(context, true, null);
+                    return new JavacFileManager(c, true, null);
                 }
             }
         });
--- a/src/share/classes/com/sun/tools/javac/file/CacheFSInfo.java	Thu Feb 24 08:40:49 2011 -0800
+++ b/src/share/classes/com/sun/tools/javac/file/CacheFSInfo.java	Fri Feb 25 12:09:33 2011 -0800
@@ -44,13 +44,13 @@
 public class CacheFSInfo extends FSInfo {
 
     /**
-     * Register a Context.Factory to create a singleton CacheFSInfo.
+     * Register a Context.Factory to create a CacheFSInfo.
      */
-    public static void preRegister(final Context context) {
+    public static void preRegister(Context context) {
         context.put(FSInfo.class, new Context.Factory<FSInfo>() {
-            public FSInfo make() {
+            public FSInfo make(Context c) {
                 FSInfo instance = new CacheFSInfo();
-                context.put(FSInfo.class, instance);
+                c.put(FSInfo.class, instance);
                 return instance;
             }
         });
--- a/src/share/classes/com/sun/tools/javac/file/JavacFileManager.java	Thu Feb 24 08:40:49 2011 -0800
+++ b/src/share/classes/com/sun/tools/javac/file/JavacFileManager.java	Fri Feb 25 12:09:33 2011 -0800
@@ -129,10 +129,10 @@
     /**
      * Register a Context.Factory to create a JavacFileManager.
      */
-    public static void preRegister(final Context context) {
+    public static void preRegister(Context context) {
         context.put(JavaFileManager.class, new Context.Factory<JavaFileManager>() {
-            public JavaFileManager make() {
-                return new JavacFileManager(context, true, null);
+            public JavaFileManager make(Context c) {
+                return new JavacFileManager(c, true, null);
             }
         });
     }
--- a/src/share/classes/com/sun/tools/javac/main/JavaCompiler.java	Thu Feb 24 08:40:49 2011 -0800
+++ b/src/share/classes/com/sun/tools/javac/main/JavaCompiler.java	Fri Feb 25 12:09:33 2011 -0800
@@ -312,7 +312,7 @@
 
     /** Construct a new compiler using a shared context.
      */
-    public JavaCompiler(final Context context) {
+    public JavaCompiler(Context context) {
         this.context = context;
         context.put(compilerKey, this);
 
--- a/src/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java	Thu Feb 24 08:40:49 2011 -0800
+++ b/src/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java	Fri Feb 25 12:09:33 2011 -0800
@@ -1045,7 +1045,7 @@
          * other values are implicitly reset.
          */
         private Context nextContext() {
-            Context next = new Context();
+            Context next = new Context(context);
 
             Options options = Options.instance(context);
             Assert.checkNonNull(options);
--- a/src/share/classes/com/sun/tools/javac/util/Context.java	Thu Feb 24 08:40:49 2011 -0800
+++ b/src/share/classes/com/sun/tools/javac/util/Context.java	Fri Feb 25 12:09:33 2011 -0800
@@ -108,7 +108,7 @@
      * instance.
      */
     public static interface Factory<T> {
-        T make();
+        T make(Context c);
     };
 
     /**
@@ -124,6 +124,8 @@
         Object old = ht.put(key, fac);
         if (old != null)
             throw new AssertionError("duplicate context value");
+        checkState(ft);
+        ft.put(key, fac); // cannot be duplicate if unique in ht
     }
 
     /** Set the value for the key in this context. */
@@ -142,7 +144,7 @@
         Object o = ht.get(key);
         if (o instanceof Factory<?>) {
             Factory<?> fac = (Factory<?>)o;
-            o = fac.make();
+            o = fac.make(this);
             if (o instanceof Factory<?>)
                 throw new AssertionError("T extends Context.Factory");
             Assert.check(ht.get(key) == o);
@@ -158,6 +160,20 @@
 
     public Context() {}
 
+    /**
+     * The table of preregistered factories.
+     */
+    private Map<Key<?>,Factory<?>> ft = new HashMap<Key<?>,Factory<?>>();
+
+    public Context(Context prev) {
+        kt.putAll(prev.kt);     // retain all implicit keys
+        ft.putAll(prev.ft);     // retain all factory objects
+        ht.putAll(prev.ft);     // init main table with factories
+    }
+
+    /*
+     * The key table, providing a unique Key<T> for each Class<T>.
+     */
     private Map<Class<?>, Key<?>> kt = new HashMap<Class<?>, Key<?>>();
 
     private <T> Key<T> key(Class<T> clss) {
@@ -198,6 +214,7 @@
     public void clear() {
         ht = null;
         kt = null;
+        ft = null;
     }
 
     private static void checkState(Map<?,?> t) {
--- a/src/share/classes/com/sun/tools/javadoc/JavadocClassReader.java	Thu Feb 24 08:40:49 2011 -0800
+++ b/src/share/classes/com/sun/tools/javadoc/JavadocClassReader.java	Fri Feb 25 12:09:33 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -44,10 +44,10 @@
         return (JavadocClassReader)instance;
     }
 
-    public static void preRegister(final Context context) {
+    public static void preRegister(Context context) {
         context.put(classReaderKey, new Context.Factory<ClassReader>() {
-            public ClassReader make() {
-                return new JavadocClassReader(context);
+            public ClassReader make(Context c) {
+                return new JavadocClassReader(c);
             }
         });
     }
--- a/src/share/classes/com/sun/tools/javadoc/JavadocEnter.java	Thu Feb 24 08:40:49 2011 -0800
+++ b/src/share/classes/com/sun/tools/javadoc/JavadocEnter.java	Fri Feb 25 12:09:33 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2008, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,10 +48,10 @@
         return (JavadocEnter)instance;
     }
 
-    public static void preRegister(final Context context) {
+    public static void preRegister(Context context) {
         context.put(enterKey, new Context.Factory<Enter>() {
-               public Enter make() {
-                   return new JavadocEnter(context);
+               public Enter make(Context c) {
+                   return new JavadocEnter(c);
                }
         });
     }
--- a/src/share/classes/com/sun/tools/javadoc/JavadocMemberEnter.java	Thu Feb 24 08:40:49 2011 -0800
+++ b/src/share/classes/com/sun/tools/javadoc/JavadocMemberEnter.java	Fri Feb 25 12:09:33 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2008, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -46,10 +46,10 @@
         return (JavadocMemberEnter)instance;
     }
 
-    public static void preRegister(final Context context) {
+    public static void preRegister(Context context) {
         context.put(memberEnterKey, new Context.Factory<MemberEnter>() {
-               public MemberEnter make() {
-                   return new JavadocMemberEnter(context);
+               public MemberEnter make(Context c) {
+                   return new JavadocMemberEnter(c);
                }
         });
     }
--- a/src/share/classes/com/sun/tools/javadoc/JavadocTodo.java	Thu Feb 24 08:40:49 2011 -0800
+++ b/src/share/classes/com/sun/tools/javadoc/JavadocTodo.java	Fri Feb 25 12:09:33 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2008, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -34,10 +34,10 @@
  *  @author Neal Gafter
  */
 public class JavadocTodo extends Todo {
-    public static void preRegister(final Context context) {
+    public static void preRegister(Context context) {
         context.put(todoKey, new Context.Factory<Todo>() {
-               public Todo make() {
-                   return new JavadocTodo(context);
+               public Todo make(Context c) {
+                   return new JavadocTodo(c);
                }
         });
     }
--- a/src/share/classes/com/sun/tools/javadoc/Messager.java	Thu Feb 24 08:40:49 2011 -0800
+++ b/src/share/classes/com/sun/tools/javadoc/Messager.java	Fri Feb 25 12:09:33 2011 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -57,23 +57,23 @@
         return (Messager)instance;
     }
 
-    public static void preRegister(final Context context,
+    public static void preRegister(Context context,
                                    final String programName) {
         context.put(logKey, new Context.Factory<Log>() {
-            public Log make() {
-                return new Messager(context,
+            public Log make(Context c) {
+                return new Messager(c,
                                     programName);
             }
         });
     }
-    public static void preRegister(final Context context,
+    public static void preRegister(Context context,
                                    final String programName,
                                    final PrintWriter errWriter,
                                    final PrintWriter warnWriter,
                                    final PrintWriter noticeWriter) {
         context.put(logKey, new Context.Factory<Log>() {
-            public Log make() {
-                return new Messager(context,
+            public Log make(Context c) {
+                return new Messager(c,
                                     programName,
                                     errWriter,
                                     warnWriter,
--- a/test/tools/javac/diags/ArgTypeCompilerFactory.java	Thu Feb 24 08:40:49 2011 -0800
+++ b/test/tools/javac/diags/ArgTypeCompilerFactory.java	Fri Feb 25 12:09:33 2011 -0800
@@ -34,6 +34,7 @@
 import com.sun.tools.javac.code.*;
 import com.sun.tools.javac.file.*;
 import com.sun.tools.javac.main.Main;
+import com.sun.tools.javac.main.JavaCompiler;
 import com.sun.tools.javac.parser.Token;
 import com.sun.tools.javac.util.*;
 import com.sun.tools.javac.util.AbstractDiagnosticFormatter.SimpleConfiguration;
@@ -107,8 +108,7 @@
             JavacTaskImpl t = (JavacTaskImpl) tool.getTask(out, fm, null, opts, null, fos);
             Context c = t.getContext();
             ArgTypeMessages.preRegister(c);
-            Options options = Options.instance(c);
-            Log.instance(c).setDiagnosticFormatter(new ArgTypeDiagnosticFormatter(options));
+            ArgTypeJavaCompiler.preRegister(c);
             Boolean ok = t.call();
 
             return ok;
@@ -144,7 +144,7 @@
                 }
             };
             JavacFileManager.preRegister(c); // can't create it until Log has been set up
-            ArgTypeDiagnosticFormatter.preRegister(c);
+            ArgTypeJavaCompiler.preRegister(c);
             ArgTypeMessages.preRegister(c);
             int result = main.compile(args.toArray(new String[args.size()]), c);
 
@@ -170,7 +170,7 @@
 
             Context c = new Context();
             JavacFileManager.preRegister(c); // can't create it until Log has been set up
-            ArgTypeDiagnosticFormatter.preRegister(c);
+            ArgTypeJavaCompiler.preRegister(c);
             ArgTypeMessages.preRegister(c);
             com.sun.tools.javac.main.Main m = new com.sun.tools.javac.main.Main("javac", out);
             int rc = m.compile(args.toArray(new String[args.size()]), c);
@@ -189,17 +189,6 @@
      * arg types.
      */
     static class ArgTypeDiagnosticFormatter extends AbstractDiagnosticFormatter {
-        static void preRegister(final Context context) {
-            context.put(Log.logKey, new Context.Factory<Log>() {
-                public Log make() {
-                    Log log = new Log(context) { };
-                    Options options = Options.instance(context);
-                    log.setDiagnosticFormatter(new ArgTypeDiagnosticFormatter(options));
-                    return log;
-                }
-            });
-
-        }
 
         ArgTypeDiagnosticFormatter(Options options) {
             super(null, new SimpleConfiguration(options,
@@ -246,14 +235,37 @@
     }
 
     /**
+     * Trivial subtype of JavaCompiler to get access to the protected compilerKey field.
+     * The factory is used to ensure that the log is initialized with an instance of
+     * ArgTypeDiagnosticFormatter before we create the required JavaCompiler.
+     */
+    static class ArgTypeJavaCompiler extends JavaCompiler {
+        static void preRegister(Context context) {
+            context.put(compilerKey, new Context.Factory<JavaCompiler>() {
+                public JavaCompiler make(Context c) {
+                    Log log = Log.instance(c);
+                    Options options = Options.instance(c);
+                    log.setDiagnosticFormatter(new ArgTypeDiagnosticFormatter(options));
+                    return new JavaCompiler(c);
+                }
+            });
+        }
+
+        // not used
+        private ArgTypeJavaCompiler() {
+            super(null);
+        }
+    }
+
+    /**
      * Diagnostic formatter which "localizes" a message as a line
      * containing a key, and a possibly empty set of descriptive strings for the
      * arg types.
      */
     static class ArgTypeMessages extends JavacMessages {
-        static void preRegister(final Context c) {
-            c.put(JavacMessages.messagesKey, new Context.Factory<JavacMessages>() {
-                public JavacMessages make() {
+        static void preRegister(Context context) {
+            context.put(JavacMessages.messagesKey, new Context.Factory<JavacMessages>() {
+                public JavacMessages make(Context c) {
                     return new ArgTypeMessages(c) {
                         @Override
                         public String getLocalizedString(Locale l, String key, Object... args) {
--- a/test/tools/javac/diags/Example.java	Thu Feb 24 08:40:49 2011 -0800
+++ b/test/tools/javac/diags/Example.java	Fri Feb 25 12:09:33 2011 -0800
@@ -522,10 +522,10 @@
                 super(context);
             }
 
-            static void preRegister(final Context c, final Set<String> keys) {
+            static void preRegister(Context c, final Set<String> keys) {
                 if (keys != null) {
                     c.put(JavacMessages.messagesKey, new Context.Factory<JavacMessages>() {
-                        public JavacMessages make() {
+                        public JavacMessages make(Context c) {
                             return new MessageTracker(c) {
                                 @Override
                                 public String getLocalizedString(Locale l, String key, Object... args) {
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/tools/javac/util/context/T7021650.java	Fri Feb 25 12:09:33 2011 -0800
@@ -0,0 +1,216 @@
+/*
+ * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 7021650
+ * @summary Fix Context issues
+ * @library ../../lib
+ * @build JavacTestingAbstractProcessor T7021650
+ * @run main T7021650
+ */
+
+import java.io.*;
+import java.net.*;
+import java.util.*;
+import javax.annotation.processing.*;
+import javax.lang.model.element.*;
+import javax.tools.*;
+
+import com.sun.tools.javac.comp.Attr;
+import com.sun.tools.javac.file.JavacFileManager;
+import com.sun.tools.javac.main.Main;
+import com.sun.tools.javac.processing.JavacProcessingEnvironment;
+import com.sun.tools.javac.util.Context;
+
+public class T7021650 extends JavacTestingAbstractProcessor {
+    public static void main(String... args) throws Exception {
+        new T7021650().run();
+    }
+
+    static File testSrc = new File(System.getProperty("test.src"));
+    static final int MAX_ROUNDS = 3;
+
+    /**
+     * Perform a compilation with custom factories registered in the context,
+     * and verify that corresponding objects are created in each round.
+     */
+    void run() throws Exception {
+        Counter demoCounter = new Counter();
+        Counter myAttrCounter = new Counter();
+
+        Context context = new Context();
+        // Use a custom file manager which creates classloaders for annotation
+        // processors with a sensible delegation parent, so that all instances
+        // of test classes come from the same class loader. This is important
+        // because the test performs class checks on the instances of classes
+        // found in the context for each round or processing.
+        context.put(JavaFileManager.class, new Context.Factory<JavaFileManager>() {
+            public JavaFileManager make(Context c) {
+                return new JavacFileManager(c, true, null) {
+                    @Override
+                    protected ClassLoader getClassLoader(URL[] urls) {
+                        return new URLClassLoader(urls, T7021650.class.getClassLoader());
+                    }
+                };
+            }
+        });
+
+        Demo.preRegister(context, demoCounter);
+        MyAttr.preRegister(context, myAttrCounter);
+
+        String[] args = {
+            "-d", ".",
+            "-processor", T7021650.class.getName(),
+            "-XprintRounds",
+            new File(testSrc, T7021650.class.getName() + ".java").getPath()
+        };
+
+        compile(context, args);
+
+        // Expect to create Demo for initial round, then MAX_ROUNDS in which
+        // GenX files are generated, then standard final round of processing.
+        checkEqual("demoCounter", demoCounter.count, MAX_ROUNDS + 2);
+
+        // Expect to create MyAttr for same processing rounds as for Demo,
+        // plus additional context for final compilation.
+        checkEqual("myAttrCounter", myAttrCounter.count, MAX_ROUNDS + 3);
+    }
+
+    void compile(Context context, String... args) throws Exception {
+        StringWriter sw = new StringWriter();
+        PrintWriter pw = new PrintWriter(sw);
+        Main m = new Main("javac", pw);
+        int rc = m.compile(args, context);
+        pw.close();
+        String out = sw.toString();
+        if (!out.isEmpty())
+            System.err.println(out);
+        if (rc != 0)
+            throw new Exception("compilation failed unexpectedly: rc=" + rc);
+    }
+
+    void checkEqual(String label, int found, int expect) throws Exception {
+        if (found != expect)
+            throw new Exception("unexpected value for " + label
+                    + ": expected " + expect
+                    + ": found " + found);
+    }
+
+    //---------------
+
+    /*
+     * A custom class unknown to javac but nonetheless registered in the context.
+     */
+    static class Demo {
+        static void preRegister(Context context, final Counter counter) {
+            context.put(Demo.class, new Context.Factory<Demo>() {
+                public Demo make(Context c) {
+                    counter.count++;
+                    return new Demo(c);
+                }
+            });
+        }
+
+        Demo(Context c) {
+            c.put(Demo.class, this);
+        }
+
+        static Demo instance(Context context) {
+            return context.get(Demo.class);
+        }
+    }
+
+    /**
+     * A custom version of a standard javac component.
+     */
+    static class MyAttr extends Attr {
+        static void preRegister(Context context, final Counter counter) {
+            context.put(attrKey, new Context.Factory<Attr>() {
+                public Attr make(Context c) {
+                    counter.count++;
+                    return new MyAttr(c);
+                }
+            });
+        }
+
+        MyAttr(Context c) {
+            super(c);
+        }
+    }
+
+    static class Counter {
+        int count;
+    }
+
+    //---------------
+
+    int round = 0;
+
+    @Override
+    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
+        round++;
+
+        Context context = ((JavacProcessingEnvironment) processingEnv).getContext();
+
+        // verify items in context as expected
+        check("Demo", Demo.instance(context), Demo.class);
+        check("Attr", Attr.instance(context), MyAttr.class);
+
+        // For a few rounds, generate new source files, so that we can check whether
+        // values in the context are correctly handled in subsequent processing rounds
+        if (round <= MAX_ROUNDS) {
+            String pkg = "p";
+            String currClass = "Gen" + round;
+            String curr = pkg + "." + currClass;
+            String next = (pkg + ".Gen" + (round + 1));
+            StringBuilder text = new StringBuilder();
+            text.append("package ").append(pkg).append(";\n");
+            text.append("public class ").append(currClass).append(" {\n");
+            if (round < MAX_ROUNDS)
+                text.append("    ").append(next).append(" x;\n");
+            text.append("}\n");
+
+            try {
+                JavaFileObject fo = filer.createSourceFile(curr);
+                Writer out = fo.openWriter();
+                try {
+                    out.write(text.toString());
+                } finally {
+                    out.close();
+                }
+            } catch (IOException e) {
+                throw new Error(e);
+            }
+        }
+
+        return true;
+    }
+
+    void check(String label, Object o, Class<?> clazz) {
+        if (o == null)
+            throw new IllegalStateException(label + ": no item found");
+        if (!clazz.isAssignableFrom(o.getClass()))
+            throw new IllegalStateException(label + ": unexpected class: " + o.getClass());
+    }
+}