added some missing classes from last commit

.gitignore

@@ -3,3 +3,4 @@ classes/
 output/
 temp/
 
+!/src/org/yawlfoundation/yawl/balancer/output/

src/org/yawlfoundation/yawl/balancer/output/AbstractLoadOutputter.java

@@ -0,0 +1,120 @@
+package org.yawlfoundation.yawl.balancer.output;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.Map;
+
+/**
+ * @author Michael Adams
+ * @date 21/8/17
+ */
+abstract class AbstractLoadOutputter {
+
+    protected FileWriter _out;
+
+
+    public AbstractLoadOutputter(String baseFileName, String engineName) {
+        try {
+            _out = openFile(baseFileName, engineName);
+            writeHeader();
+        }
+        catch (IOException ioe) {
+            if (_out != null) _out = null;
+        }
+    }
+
+
+    abstract void writeValues(Map<String, String> values) throws IOException;
+
+    abstract String getHeader();
+
+
+    public void closeFile() {
+        if (_out != null) {
+            try {
+                _out.flush();
+                _out.close();
+            }
+            catch (IOException ioe) {
+                // we tried
+            }
+        }
+    }
+
+
+    public void add(String line) {
+        if (_out != null) {
+            try {
+                for (String sub : line.split("\\r?\\n")) {
+                    writeTime();
+                    _out.write(sub);
+                    _out.write('\n');
+                }
+                _out.flush();
+            }
+            catch (IOException ioe) {
+                // forget it
+            }
+        }
+    }
+
+
+    public void add(Map<String, String> values) {
+        if (_out != null) {
+            try {
+                writeTime();
+                writeValues(values);
+                _out.write('\n');
+                _out.flush();
+            }
+            catch (IOException ioe) {
+                // forget it
+            }
+        }
+    }
+
+
+    private void writeHeader() throws IOException {
+        if (_out != null) {
+            _out.write(getHeader());
+            _out.write('\n');
+        }
+    }
+
+
+    private void writeTime() throws IOException {
+        if (_out != null) {
+            Date date = new Date();
+            String fDate = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
+                    .format(new Date());
+            _out.write(fDate);
+            _out.write("," + date.getTime() + ",");
+        }
+    }
+
+
+    private FileWriter openFile(String baseFileName, String engineName) throws IOException {
+        File f = getFile(baseFileName, engineName);
+        if (f.createNewFile()) {
+            return new FileWriter(f);
+        }
+        return null;
+    }
+
+
+    private File getFile(String baseFileName, String engineName) {
+        String root = System.getenv("CATALINA_HOME");
+        String baseName = root + "/logs/" + baseFileName + '_' + engineName;
+        String extn = ".log";
+        File f = new File(baseName + extn);
+        int i = 1;
+        while (f.exists()) {
+           f  = new File(baseName + "_" + i++ + extn);
+        }
+        return f;
+    }
+
+}

src/org/yawlfoundation/yawl/balancer/output/BusynessOutputter.java

@@ -0,0 +1,45 @@
+package org.yawlfoundation.yawl.balancer.output;
+
+import java.io.IOException;
+import java.util.Map;
+
+/**
+ * @author Michael Adams
+ * @date 21/8/17
+ */
+public class BusynessOutputter extends AbstractLoadOutputter {
+
+
+    public BusynessOutputter(String engineName) {
+        super("busyness", engineName);
+    }
+
+
+    protected void writeValues(Map<String, String> values) throws IOException {
+        _out.write(values.get("cpu_process"));
+        _out.write(',');
+        _out.write(values.get("cpu_system"));
+        _out.write(',');
+        _out.write(values.get("thread_count"));
+        _out.write(',');
+        _out.write(values.get("threads_busy"));
+        _out.write(',');
+        _out.write(values.get("threads_free"));
+        _out.write(',');
+        _out.write(values.get("process_time_factor"));
+        _out.write(',');
+        _out.write(values.get("requests_factor"));
+        _out.write(',');
+        _out.write(values.get("threads_factor"));
+        _out.write(',');
+        _out.write(values.get("busyness"));
+    }
+
+
+    protected String getHeader() {
+        return "time,timestamp,cpu_process,cpu_system,thread_count," +
+               "threads_busy,threads_free,process_time_factor,requests_factor," +
+               "threads_factor,busyness";
+    }
+
+}

src/org/yawlfoundation/yawl/balancer/output/RequestStatOutputter.java

@@ -0,0 +1,29 @@
+package org.yawlfoundation.yawl.balancer.output;
+
+import java.io.IOException;
+import java.util.Map;
+
+/**
+ * @author Michael Adams
+ * @date 21/8/17
+ */
+public class RequestStatOutputter extends AbstractLoadOutputter {
+
+
+    public RequestStatOutputter(String engineName) {
+        super("requests", engineName);
+    }
+
+
+    protected void writeValues(Map<String, String> values) throws IOException { }
+
+
+    protected String getHeader() {
+        StringBuilder sb = new StringBuilder();
+        sb.append("time,timestamp,name,min,max,mean,count,perSec,");
+        sb.append("prevMin,prevMax,prevMean,prevCount,prevPerSec,");
+        sb.append("allMin,allMax,allMean,allCount,allPerSec");
+        return sb.toString();
+    }
+
+}

src/org/yawlfoundation/yawl/engine/YWorkItemRepository.java

@@ -191,7 +191,7 @@ public void cleanseRepository() {
                 if (! foundOne) itemsToRemove.add(workitem.getIDString());
             }
         }
-        removeItems(itemsToRemove);
+        if (! itemsToRemove.isEmpty()) removeItems(itemsToRemove);
     }