1 files changed, 60 insertions, 0 deletions
diff --git a/kamon-annotation/src/main/scala/kamon/annotation/el/EnhancedELProcessor.scala b/kamon-annotation/src/main/scala/kamon/annotation/el/EnhancedELProcessor.scala
new file mode 100644
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+++ b/kamon-annotation/src/main/scala/kamon/annotation/el/EnhancedELProcessor.scala
@@ -0,0 +1,60 @@
+/*
+ * =========================================================================================
+ * Copyright © 2013-2015 the kamon project <http://kamon.io/>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the
+ * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+ * either express or implied. See the License for the specific language governing permissions
+ * and limitations under the License.
+ * =========================================================================================
+ */
+
+package kamon.annotation.el
+
+import javax.el.ELProcessor
+
+import kamon.Kamon
+import kamon.annotation.Annotation
+
+import scala.util.{ Failure, Success, Try }
+
+/**
+ * Pimp ELProcessor injecting some useful methods.
+ */
+object EnhancedELProcessor {
+  private val Pattern = """[#|$]\{(.*)\}""".r
+
+  implicit class Syntax(val processor: ELProcessor) extends AnyVal {
+    import scala.collection.JavaConverters._
+
+    def evalToString(expression: String): String = extract(expression).map { str ⇒
+      eval[String](str) match {
+        case Success(value) ⇒ value
+        case Failure(cause) ⇒
+          Kamon(Annotation).log.error(s"${cause.getMessage} -> we will complete the operation with 'unknown' string")
+          "unknown"
+      }
+    } getOrElse expression
+
+    def evalToMap(expression: String): Map[String, String] = extract(expression).map { str ⇒
+      eval[Map[String, String]](s"{$str}") match {
+        case Success(value) ⇒ value.asInstanceOf[java.util.HashMap[String, String]].asScala.toMap
+        case Failure(cause) ⇒
+          Kamon(Annotation).log.error(s"${cause.getMessage} -> we will complete the operation with an empty map")
+          Map.empty[String, String]
+      }
+    } getOrElse Map.empty[String, String]
+
+    private def eval[A](str: String): Try[A] = Try(processor.eval(str).asInstanceOf[A])
+
+    private def extract(expression: String): Option[String] = expression match {
+      case Pattern(ex) ⇒ Some(ex)
+      case _           ⇒ None
+    }
+  }
+}