do not print trace for compilation-canceled exception

jps/jps-builders/src/org/jetbrains/jps/javac/CompilationCanceledException.java

@@ -0,0 +1,16 @@
+package org.jetbrains.jps.javac;
+
+/**
+ * @author Eugene Zhuravlev
+ *         Date: 4/2/12
+ */
+class CompilationCanceledException extends RuntimeException{
+  CompilationCanceledException() {
+    super("Compilation canceled");
+  }
+
+  @Override
+  public synchronized Throwable fillInStackTrace() {
+    return this;
+  }
+}

jps/jps-builders/src/org/jetbrains/jps/javac/JavacFileManager.java

@@ -210,12 +210,7 @@ class JavacFileManager extends ForwardingJavaFileManager<StandardJavaFileManager
     final int counter = (myChecksCounter + 1) % 10;
     myChecksCounter = counter;
     if (counter == 0 && myContext.isCanceled()) {
-      throw new RuntimeException("Compilation canceled") {
-        @Override
-        public Throwable fillInStackTrace() {
-          return this;
-        }
-      };
+      throw new CompilationCanceledException();
     }
   }
 }

jps/jps-builders/src/org/jetbrains/jps/javac/JavacServer.java

@@ -140,6 +140,9 @@ public class JavacServer {
       final boolean rc = JavacMain.compile(options, files, classpath, platformCp, sourcePath, outs, diagnostic, outputSink, canceledStatus);
       return JavacProtoUtil.toMessage(sessionId, JavacProtoUtil.createBuildCompletedResponse(rc));
     }
+    catch (CompilationCanceledException e) {
+      return JavacProtoUtil.toMessage(sessionId, JavacProtoUtil.createFailure(e.getMessage(), e));
+    }
     catch (Throwable e) {
       e.printStackTrace(System.err);
       return JavacProtoUtil.toMessage(sessionId, JavacProtoUtil.createFailure(e.getMessage(), e));