Document behaviour of compile and eval methods

When a valid filename is specified by the ScriptEngine.FILENAME key in the
engine scope bindings, the given script will be ignored and the file
described by the filename will be compiled (and run) instead.

Signed-off-by: Squareys <Squareys@googlemail.com>

Author: Squareys

src/main/java/org/scijava/plugins/scripting/java/JavaEngine.java

@@ -118,7 +118,9 @@ public class JavaEngine extends AbstractScriptEngine {
 	private JavaService javaService;
 
 	/**
-	 * Compiles and runs the specified {@code .java} class.
+	 * Compiles and runs the specified {@code .java} class. If a filename is set
+	 * in the engine scope bindings via the {@link ScriptEngine#FILENAME} key,
+	 * this method compiles that file and runs the resulting main class instead.
 	 * <p>
 	 * The currently active {@link JavaService} is responsible for running the
 	 * class.
@@ -149,7 +151,9 @@ public Object eval(String script) throws ScriptException {
 	}
 
 	/**
-	 * Compiles and runs the specified {@code .java} class.
+	 * Compiles and runs the specified {@code .java} class. If a filename is set
+	 * in the engine scope bindings via the {@link ScriptEngine#FILENAME} key,
+	 * this method compiles that file and runs the resulting main class instead.
 	 * <p>
 	 * The currently active {@link JavaService} is responsible for running the
 	 * class.
@@ -171,12 +175,16 @@ public Object eval(Reader reader) throws ScriptException {
 	}
 
 	/**
-	 * Compiles and runs the specified {@code .java} class.
+	 * Compiles and runs the specified {@code .java} class. If a filename is set
+	 * in the engine scope bindings via the {@link ScriptEngine#FILENAME} key,
+	 * this method compiles that file and returns its resulting main class
+	 * instead.
 	 * 
 	 * @param script the source code for a Java class
 	 * @return the compiled Java class as {@link Class}.
 	 */
 	public Class<?> compile(String script) throws ScriptException {
+		// get filename from engine scope bindings
 		final String path = (String) get(FILENAME);
 		File file = path == null ? null : new File(path);
 
@@ -244,7 +252,10 @@ public Class<?> compile(String script) throws ScriptException {
 	}
 
 	/**
-	 * Compiles and runs the specified {@code .java} class.
+	 * Compiles and runs the specified {@code .java} class. If a filename is set
+	 * in the engine scope bindings via the {@link ScriptEngine#FILENAME} key,
+	 * this method compiles that file and returns its resulting main class
+	 * instead.
 	 *
 	 * @param reader the reader producing the source code for a Java class
 	 * @return the compiled Java class as {@link Class}.