Bug 923: Remove dependency of CStruct annotation processor _generation_ and generated_class_user due to Java8 issues.

Java8's annotation processor as embedded within javac does not allow
referencing not-yet existing generated classes in a class source code
which will produce these generated classes via the annotation process.

Example:

+++
import com.jogamp.gluegen.structgen.CStruct;

public class Lala {
  @CStruct(name="RenderingConfig", header="TestStruct01.h")
  public RenderingConfig config;
}
+++

Above example illustrates that the type 'RenderingConfig'
does not exist at time of processing the annotation.
The type will be created via the annotation process itself.

Even though we pass '-proc:only', i.e. skip java compilation,
Java8's annotation processing via javac fails in such case.

We see this as a bug within javac's annotation processing itself!

+++

This workaround splits the annotation process and using the class as
generated by the former.

To allow this to work, CStruct receives a new field 'jname'
allowing to enforce the java-name of the structure
using a dummy field type like boolean.

  @CStruct(name="RenderingConfig", jname="RenderingConfig", header="TestStruct01.h")
  public boolean dummy;

Further more CStruct can be annotated on the package, i.e. 'package-info.java',
avoiding the dependency problem altogether.
To support multiple header files and types,
'CStructs' has been introduced using an array of 'CStruct'.

  @CStructs({@CStruct(name="RenderingConfig", header="TestStruct01.h"), @CStruct(name="Pixel", header="TestStruct02.h")})
  package com.jogamp.gluegen.test.junit.structgen;

Tests:
  - Build w/ Java7 and Java8
  - Validated 'major version 50' (Java 6) class files (OK)

5 files changed, 124 insertions, 13 deletions

diff --git a/src/junit/com/jogamp/gluegen/test/junit/structgen/BuildStruct01.java b/src/junit/com/jogamp/gluegen/test/junit/structgen/BuildStruct01.java
new file mode 100644
index 0000000..7824e55
--- /dev/null
+++ b/src/junit/com/jogamp/gluegen/test/junit/structgen/BuildStruct01.java
@@ -0,0 +1,34 @@
+package com.jogamp.gluegen.test.junit.structgen;
+
+import com.jogamp.gluegen.structgen.CStruct;
+
+/**
+ * Class simply triggering CStruct annotation processor to generate the types 'RenderingConfig' etc.
+ * <p>
+ * Due to Java8 issues, see Bug 923,
+ * using {@link package-info} is more elegant to kick-off the annotation processor.
+ * </p>
+ */
+public class BuildStruct01 {
+
+    // APT is only triggered for fields,
+    // hence we use unused fields in this unit test!
+
+    // @CStruct(name="RenderingConfig", header="TestStruct01.h")
+    // MyRenderingConfig config;
+
+    // @CStruct(header="TestStruct01.h")
+    // MyRenderingConfig config;
+
+    /**
+     * Java8: We cannot use type 'RenderingConfig' yet (bug?) even if not compiling.
+     * Hence we force the type-name via 'jname' and use a dummy variable!
+     */
+    @CStruct(name="RenderingConfig", jname="RenderingConfig", header="TestStruct01.h")
+    boolean dummy1;
+
+    @CStruct(name="Pixel", jname="Pixel", header="TestStruct02.h")
+    boolean dummy2;
+
+    public static void initSingleton() {}
+}
diff --git a/src/junit/com/jogamp/gluegen/test/junit/structgen/TestStruct02.h b/src/junit/com/jogamp/gluegen/test/junit/structgen/TestStruct02.h
new file mode 100644
index 0000000..64fda78
--- /dev/null
+++ b/src/junit/com/jogamp/gluegen/test/junit/structgen/TestStruct02.h
@@ -0,0 +1,14 @@
+//
+// TestStruct02.h
+//
+
+#include "TestStruct01.h"
+
+typedef struct {
+    float r, g, b, a;
+} Col4f;
+
+typedef struct {
+	Col4f color;
+	Vec3f pos;
+} Pixel;
diff --git a/src/junit/com/jogamp/gluegen/test/junit/structgen/TestStructGen01.java b/src/junit/com/jogamp/gluegen/test/junit/structgen/TestStructGen01.java
index 23b1624..74f0552 100644
--- a/src/junit/com/jogamp/gluegen/test/junit/structgen/TestStructGen01.java
+++ b/src/junit/com/jogamp/gluegen/test/junit/structgen/TestStructGen01.java
@@ -1,26 +1,23 @@
 package com.jogamp.gluegen.test.junit.structgen;
 
-import com.jogamp.gluegen.structgen.CStruct;
 import com.jogamp.junit.util.JunitTracer;
 
 import org.junit.Assert;
+import org.junit.BeforeClass;
 import org.junit.Test;
-
 import org.junit.FixMethodOrder;
 import org.junit.runners.MethodSorters;
 
 @FixMethodOrder(MethodSorters.NAME_ASCENDING)
 public class TestStructGen01 extends JunitTracer {
 
-    // APT is only triggered for fields,
-    // hence we use unused fields in this unit test!
-    
-    // @CStruct(name="RenderingConfig", header="TestStruct01.h")
-    // MyRenderingConfig config;
-    
-    @CStruct(header="TestStruct01.h")
-    RenderingConfig config0;
-    
+    @BeforeClass
+    public static void init() {
+        // Enforce dependency,
+        // i.e. CStruct annotation processor to generate the types 'RenderingConfig' etc.
+        BuildStruct01.initSingleton();
+    }
+
     @Test
     public void test01() {
         RenderingConfig config = RenderingConfig.create();
@@ -46,10 +43,10 @@ public class TestStructGen01 extends JunitTracer {
         cam_orig.setY(1);
         cam_orig.setZ(2);
     }
-    
+
     public static void main(String args[]) {
         String tstname = TestStructGen01.class.getName();
         org.junit.runner.JUnitCore.main(tstname);
     }
-    
+
 }
diff --git a/src/junit/com/jogamp/gluegen/test/junit/structgen/TestStructGen02.java b/src/junit/com/jogamp/gluegen/test/junit/structgen/TestStructGen02.java
new file mode 100644
index 0000000..a8f0e52
--- /dev/null
+++ b/src/junit/com/jogamp/gluegen/test/junit/structgen/TestStructGen02.java
@@ -0,0 +1,51 @@
+package com.jogamp.gluegen.test.junit.structgen;
+
+import com.jogamp.junit.util.JunitTracer;
+
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.FixMethodOrder;
+import org.junit.runners.MethodSorters;
+
+@FixMethodOrder(MethodSorters.NAME_ASCENDING)
+public class TestStructGen02 extends JunitTracer {
+
+    @BeforeClass
+    public static void init() {
+        // Enforce dependency,
+        // i.e. CStruct annotation processor to generate the types 'RenderingConfig' etc.
+        BuildStruct01.initSingleton();
+    }
+
+    @Test
+    public void test01() {
+        final Pixel pixel = Pixel.create();
+        final Col4f color = pixel.getColor();
+        color.setR(1f);
+        color.setG(2f);
+        color.setB(3f);
+        color.setA(4f);
+        final Vec3f pos = pixel.getPos();
+        pos.setX(0.5f);
+        pos.setY(0.6f);
+        pos.setZ(0.7f);
+
+        Pixel pixel2 = Pixel.create(pixel.getBuffer());
+        final Col4f color2 = pixel2.getColor();
+        Assert.assertEquals(color.getR(), color2.getR(), 0.0001f);
+        Assert.assertEquals(color.getG(), color2.getG(), 0.0001f);
+        Assert.assertEquals(color.getB(), color2.getB(), 0.0001f);
+        Assert.assertEquals(color.getA(), color2.getA(), 0.0001f);
+        final Vec3f pos2 = pixel2.getPos();
+        Assert.assertEquals(pos.getX(), pos2.getX(), 0.0001f);
+        Assert.assertEquals(pos.getY(), pos2.getY(), 0.0001f);
+        Assert.assertEquals(pos.getZ(), pos2.getZ(), 0.0001f);
+    }
+
+    public static void main(String args[]) {
+        String tstname = TestStructGen02.class.getName();
+        org.junit.runner.JUnitCore.main(tstname);
+    }
+
+}
diff --git a/src/junit/com/jogamp/gluegen/test/junit/structgen/package-info.java b/src/junit/com/jogamp/gluegen/test/junit/structgen/package-info.java
new file mode 100644
index 0000000..d009c5f
--- /dev/null
+++ b/src/junit/com/jogamp/gluegen/test/junit/structgen/package-info.java
@@ -0,0 +1,15 @@
+/**
+ * Package scope generation of {@link CStruct}s
+ * avoiding Java8 issues w/ annotation processing
+ * where the generated class is not yet available.
+ * <p>
+ * See Bug 923.
+ * </p>
+ * @see BuildStruct01
+ */
+@CStructs({@CStruct(name="RenderingConfig", header="TestStruct01.h"), @CStruct(name="Pixel", header="TestStruct02.h")})
+package com.jogamp.gluegen.test.junit.structgen;
+
+import com.jogamp.gluegen.structgen.CStructs;
+import com.jogamp.gluegen.structgen.CStruct;
+