Adding another way to extract the value, this time into a "natural" Java object.

I came into this use case while working on the workflow, but I think it's useful in other context as well,
such as Scriptler plugin needing to define some parameters.

core/src/main/java/hudson/model/BooleanParameterValue.java

@@ -48,6 +48,11 @@ public class BooleanParameterValue extends ParameterValue {
         this.value = value;
     }
 
+    @Override
+    public Boolean getValue() {
+        return value;
+    }
+
     /**
      * Exposes the name/value as an environment variable.
      */

core/src/main/java/hudson/model/FileParameterValue.java

@@ -96,6 +96,11 @@ public class FileParameterValue extends ParameterValue {
         return location;
     }
 
+    @Override
+    public Object getValue() {
+        return file;
+    }
+
     /**
      * Exposes the originalFileName as an environment variable.
      */

core/src/main/java/hudson/model/JobParameterValue.java

@@ -37,6 +37,11 @@ public class JobParameterValue extends ParameterValue {
         this.job = job;
     }
 
+    @Override
+    public Job getValue() {
+        return job;
+    }
+
     /**
      * Exposes the name/value as an environment variable.
      */

core/src/main/java/hudson/model/ParameterValue.java

@@ -278,6 +278,16 @@ public abstract class ParameterValue implements Serializable {
         return false;
     }
 
+    /**
+     * Returns the most natural Java object that represents the actual value, like
+     * boolean, string, etc.
+     *
+     * If there's nothing that really fits the bill, the callee can return {@code this}.
+     */
+    public Object getValue() {
+        return null;
+    }
+
     /**
      * Controls where the build (that this parameter is submitted to) will happen.
      *

core/src/main/java/hudson/model/RunParameterValue.java

@@ -66,7 +66,11 @@ public class RunParameterValue extends ParameterValue {
     public String getNumber() {
     	return runId.split("#")[1];
     }
-    
+
+    @Override
+    public Run getValue() {
+        return getRun();
+    }
 
     /**
      * Exposes the name/value as an environment variable.

core/src/main/java/hudson/model/StringParameterValue.java

@@ -65,9 +65,13 @@ public class StringParameterValue extends ParameterValue {
             }
         };
     }
-    
 
-	@Override
+    @Override
+    public Object getValue() {
+        return value;
+    }
+
+    @Override
 	public int hashCode() {
 		final int prime = 31;
 		int result = super.hashCode();