Index: /trunk/EventBenchCore/src/de/ugoe/cs/eventbench/coverage/CoverageCalculator.java
===================================================================
--- /trunk/EventBenchCore/src/de/ugoe/cs/eventbench/coverage/CoverageCalculator.java	(revision 106)
+++ /trunk/EventBenchCore/src/de/ugoe/cs/eventbench/coverage/CoverageCalculator.java	(revision 107)
@@ -1,4 +1,5 @@
 package de.ugoe.cs.eventbench.coverage;
 
+import java.security.InvalidParameterException;
 import java.util.Collection;
 import java.util.LinkedHashMap;
@@ -75,9 +76,8 @@
 	 * 
 	 * @param process
-	 *            stochastic process used for coverage calculations; if it is
-	 *            zero, not all calculations are possible
+	 *            stochastic process used for coverage calculations; must not be null
 	 * @param sequences
 	 *            sequences for which the coverage is calculated; must not be
-	 *            null.
+	 *            null
 	 * @param length
 	 *            length of the subsequences for which the coverage is analyzed;
@@ -86,5 +86,13 @@
 	public CoverageCalculator(IStochasticProcess process,
 			Collection<List<? extends Event<?>>> sequences, int length) {
-		// TODO check parameters
+		if( process==null ) {
+			throw new InvalidParameterException("process must not be null");
+		}
+		if( sequences==null ) {
+			throw new InvalidParameterException("sequences must not be null");
+		}
+		if( length<=0 ) {
+			throw new InvalidParameterException("length must be >0; actual value: " + length);
+		}
 		this.process = process;
 		this.sequences = sequences;