From d969b3c0a85ccc7edac586226a90b51dbc1924c1 Mon Sep 17 00:00:00 2001
From: Dmitry Gusev <dmitry.gusev@gmail.com>
Date: Thu, 22 May 2014 18:28:05 +0400
Subject: [PATCH] Don't throw exception every time EclipseUtils.parse is used
 on platforms without Java8 support

---
 .../eclipse/tapestry5/EclipseUtils.java       | 32 +++++++++++++------
 1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/com.anjlab.eclipse.tapestry5/src/com/anjlab/eclipse/tapestry5/EclipseUtils.java b/com.anjlab.eclipse.tapestry5/src/com/anjlab/eclipse/tapestry5/EclipseUtils.java
index 4892cc1..eb80e87 100644
--- a/com.anjlab.eclipse.tapestry5/src/com/anjlab/eclipse/tapestry5/EclipseUtils.java
+++ b/com.anjlab.eclipse.tapestry5/src/com/anjlab/eclipse/tapestry5/EclipseUtils.java
@@ -18,7 +18,6 @@
 import org.eclipse.jdt.core.IType;
 import org.eclipse.jdt.core.JavaCore;
 import org.eclipse.jdt.core.JavaModelException;
-import org.eclipse.jdt.core.dom.AST;
 import org.eclipse.jdt.core.dom.ASTParser;
 import org.eclipse.jdt.core.dom.CompilationUnit;
 import org.eclipse.jdt.core.dom.Name;
@@ -327,7 +326,6 @@ public static CompilationUnit parse(ICompilationUnit unit)
         return parse(source);
     }
 
-    @SuppressWarnings("deprecation")    //  -- Since Eclipse Luna
     public static CompilationUnit parse(String source)
     {
         if (source == null)
@@ -335,22 +333,36 @@ public static CompilationUnit parse(String source)
             throw new IllegalStateException(SOURCE_NOT_FOUND);
         }
         
-        ASTParser parser;
-        try
-        {
-            int parserLevel = 8;  // AST.JLS8 -- Since Eclipse Luna
-            parser = ASTParser.newParser(parserLevel);
-        }
-        catch (IllegalArgumentException e)
+        if (parserLevel == -1)
         {
-            parser = ASTParser.newParser(AST.JLS4);
+            parserLevel = getParserLevel();
         }
+        
+        ASTParser parser = ASTParser.newParser(parserLevel);
         parser.setKind(ASTParser.K_COMPILATION_UNIT);
         parser.setSource(source.toCharArray());
         parser.setResolveBindings(true);
         return (CompilationUnit) parser.createAST(null);
     }
 
+    private static int parserLevel = -1;
+
+    private static int getParserLevel()
+    {
+        try
+        {
+            int JLS8 = 8;
+            // Try to use Java 8's AST.JLS8
+            ASTParser.newParser(JLS8);
+            return JLS8;
+        }
+        catch (IllegalArgumentException e)
+        {
+            //  Fallback to Java 7
+            return 4; //  AST.JLS4
+        }
+    }
+
     public static IProject getProjectFromSelection(ISelection selection)
     {
         if (selection instanceof ITreeSelection)