Added some comments

src/main/java/kieker/diagnosis/common/domain/AbstractOperationCall.java

@@ -19,6 +19,16 @@ package kieker.diagnosis.common.domain;
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * This is an abstract base for classes representing operation calls (also called executions) within this application. As it can has multiple children, an instance of this class
+ * can represent a whole call tree. This class implements the both methods {@link OperationCall#equals(Object)} and {@link OperationCall#hashCode()}, allowing to easily check
+ * whether two traces are equal and should be in the same equivalence class.
+ *
+ * @author Nils Christian Ehmke
+ *
+ * @param <T>
+ *            The precise type of the children. This should usually be the implementing class itself.
+ */
 public abstract class AbstractOperationCall<T extends AbstractOperationCall<T>> {
 
 	private final List<T> children = new ArrayList<>();

src/main/java/kieker/diagnosis/common/domain/AbstractTrace.java

@@ -17,13 +17,13 @@
 package kieker.diagnosis.common.domain;
 
 /**
- * This is an abstract base for classes representing traces within this application. Technically this class is just a container for a single {@link OperationCall} instance
- * representing the root call of a whole call trace. Furthermore, this class implements the both methods {@link AbstractTrace#equals(Object)} and {@link AbstractTrace#hashCode()},
- * allowing to put traces for example into a map to aggregate them.
+ * This is an abstract base for classes representing traces (a tree of operation calls) within this application. Technically this class is just a container for a single
+ * {@link AbstractOperationCall} instance representing the root call of a whole call tree. Furthermore, this class implements the methods {@link AbstractTrace#equals(Object)} and
+ * {@link AbstractTrace#hashCode()}, allowing to put traces for example into a map to aggregate them.
  *
  * @author Nils Christian Ehmke
  */
-public abstract class AbstractTrace<T extends AbstractOperationCall<T>> { // NOPMD (abstract class without abstract methods)
+public abstract class AbstractTrace<T extends AbstractOperationCall<T>> {
 
 	private final T rootOperationCall;
 

src/main/java/kieker/diagnosis/common/domain/AggregatedOperationCall.java

@@ -16,6 +16,12 @@
 
 package kieker.diagnosis.common.domain;
 
+/**
+ * This class represents an aggregated operation call within this application. It adds some properties that are only available due to aggregation, like the average duration of all
+ * calls.
+ *
+ * @author Nils Christian Ehmke
+ */
 public final class AggregatedOperationCall extends AbstractOperationCall<AggregatedOperationCall> {
 
 	private long totalDuration;

src/main/java/kieker/diagnosis/common/domain/AggregatedTrace.java

@@ -19,7 +19,7 @@ package kieker.diagnosis.common.domain;
 import java.util.List;
 
 /**
- * This class represents an aggregated trace (or a trace equivalence class) within this application.
+ * This class represents an aggregated trace (also called a trace equivalence class) within this application.
  *
  * @author Nils Christian Ehmke
  */

src/main/java/kieker/diagnosis/common/domain/OperationCall.java

@@ -17,9 +17,8 @@
 package kieker.diagnosis.common.domain;
 
 /**
- * This class represents an operation call (or an execution) within this application. As it can has multiple children, an instance of this class can represent a whole call tree.
- * This class implements the both methods {@link OperationCall#equals(Object)} and {@link OperationCall#hashCode()}, allowing to easily check whether two traces are equal (aside
- * from some varying properties like the duration) and should be in the same equivalence class.
+ * This class represents a concrete operation call within this application. It adds some properties that are only required for concrete operation calls, like the trace ID and the
+ * duration. It extends the call tree mechanism (inherited from {@link AbstractOperationCall}) by a parent, allowing to navigate in both directions within the tree.
  *
  * @author Nils Christian Ehmke
  */

src/main/java/kieker/diagnosis/common/domain/Trace.java

@@ -17,7 +17,7 @@
 package kieker.diagnosis.common.domain;
 
 /**
- * This class represents an actual trace (a sequence of operation calls) within this application.
+ * This class represents a concrete trace within this application. It adds some properties that are only required for concrete traces, like the trace ID.
  *
  * @author Nils Christian Ehmke
  */

src/main/java/kieker/diagnosis/common/model/importer/ImportAnalysisConfiguration.java

@@ -36,7 +36,7 @@ import teetime.stage.CollectorSink;
 import teetime.stage.MultipleInstanceOfFilter;
 
 /**
- * A configuration for the import and analysis of monitoring logs.
+ * A {@code TeeTime} configuration for the import and analysis of monitoring logs.
  *
  * @author Nils Christian Ehmke
  */

src/main/java/kieker/diagnosis/common/model/importer/stages/AbstractStage.java

@@ -21,9 +21,9 @@ import teetime.framework.OutputPort;
 
 /**
  * This is a abstract base for {@code TeeTime} stages with exactly one input and one output port.
- * 
+ *
  * @author Nils Christian Ehmke
- * 
+ *
  * @param <I>
  *            The type of the input port.
  * @param <O>

src/main/java/kieker/diagnosis/common/model/importer/stages/AggregatedTraceStatisticsDecorator.java

@@ -25,6 +25,11 @@ import kieker.diagnosis.common.domain.AggregatedTrace;
 import kieker.diagnosis.common.domain.OperationCall;
 import kieker.diagnosis.common.domain.Trace;
 
+/**
+ * This class is a {@code TeeTime} stage adding statistics (via the corresponding setters) to instances of {@link AggregatedTrace}. The traces are forwarded to the output port.
+ *
+ * @author Nils Christian Ehmke
+ */
 public final class AggregatedTraceStatisticsDecorator extends AbstractStage<AggregatedTrace, AggregatedTrace> {
 
 	@Override

src/main/java/kieker/diagnosis/common/model/importer/stages/TraceAggregationComposite.java

@@ -33,6 +33,11 @@ import teetime.stage.CollectorSink;
 import teetime.stage.basic.distributor.CopyByReferenceStrategy;
 import teetime.stage.basic.distributor.Distributor;
 
+/**
+ * This is a composite {@code TeeTime} stage which aggregates incoming traces, adds statistical data and stores the aggregated traces.
+ *
+ * @author Nils Christian Ehmke
+ */
 public final class TraceAggregationComposite extends CompositeStage {
 
 	private final TraceAggregator aggregator;

src/main/java/kieker/diagnosis/common/model/importer/stages/TraceReconstructionComposite.java

@@ -34,6 +34,11 @@ import teetime.stage.CollectorSink;
 import teetime.stage.basic.distributor.CopyByReferenceStrategy;
 import teetime.stage.basic.distributor.Distributor;
 
+/**
+ * This class is a composite {@code TeeTime} stage, which reconstruct traces based on the incoming records, adds statistical data and stores the traces.
+ *
+ * @author Nils Christian Ehmke
+ */
 public final class TraceReconstructionComposite extends CompositeStage {
 
 	private final TraceReconstructor reconstructor;

src/main/java/kieker/diagnosis/common/model/importer/stages/TraceStatisticsDecorator.java

@@ -19,6 +19,11 @@ package kieker.diagnosis.common.model.importer.stages;
 import kieker.diagnosis.common.domain.OperationCall;
 import kieker.diagnosis.common.domain.Trace;
 
+/**
+ * This class is a {@code TeeTime} stage adding statistics (via the corresponding setters) to instances of {@link Trace}. The traces are forwarded to the output port.
+ *
+ * @author Nils Christian Ehmke
+ */
 public final class TraceStatisticsDecorator extends AbstractStage<Trace, Trace> {
 
 	@Override