fix: stabilize Meeting Scheduling benchmark

src/main/java/ai/timefold/solver/benchmarks/examples/common/persistence/AbstractJsonSolutionFileIO.java

@@ -1,6 +1,5 @@
 package ai.timefold.solver.benchmarks.examples.common.persistence;
 
-import java.io.File;
 import java.util.Collection;
 import java.util.LinkedHashMap;
 import java.util.Map;
@@ -58,9 +57,4 @@ protected <Key_, Value_, Index_> Map<Key_, Value_> deduplicateMap(Map<Key_, Valu
         return newMap;
     }
 
-    @Override
-    public final void write(Solution_ solution, File outputSolutionFile) {
-        throw new UnsupportedOperationException();
-    }
-
 }

src/main/java/ai/timefold/solver/benchmarks/examples/meetingscheduling/app/MeetingSchedulingApp.java

@@ -2,7 +2,7 @@
 
 import ai.timefold.solver.benchmarks.examples.common.app.CommonApp;
 import ai.timefold.solver.benchmarks.examples.meetingscheduling.domain.MeetingSchedule;
-import ai.timefold.solver.benchmarks.examples.meetingscheduling.persistence.MeetingSchedulingXlsxFileIO;
+import ai.timefold.solver.benchmarks.examples.meetingscheduling.persistence.MeetingSchedulingSolutionFileIO;
 import ai.timefold.solver.persistence.common.api.domain.solution.SolutionFileIO;
 
 public class MeetingSchedulingApp extends CommonApp<MeetingSchedule> {
@@ -13,7 +13,7 @@ public class MeetingSchedulingApp extends CommonApp<MeetingSchedule> {
     public static final String DATA_DIR_NAME = "meetingscheduling";
 
     public static void main(String[] args) {
-        var solution = new MeetingSchedulingApp().solve("100meetings-320timegrains-5rooms.xlsx");
+        var solution = new MeetingSchedulingApp().solve("100meetings-320timegrains-5rooms.json");
         System.out.println("Done: " + solution);
     }
 
@@ -25,7 +25,7 @@ public MeetingSchedulingApp() {
 
     @Override
     public SolutionFileIO<MeetingSchedule> createSolutionFileIO() {
-        return new MeetingSchedulingXlsxFileIO();
+        return new MeetingSchedulingSolutionFileIO();
     }
 
 }

src/main/java/ai/timefold/solver/benchmarks/examples/meetingscheduling/domain/Attendance.java

@@ -1,7 +1,18 @@
 package ai.timefold.solver.benchmarks.examples.meetingscheduling.domain;
 
 import ai.timefold.solver.benchmarks.examples.common.domain.AbstractPersistable;
-
+import ai.timefold.solver.benchmarks.examples.common.persistence.jackson.JacksonUniqueIdGenerator;
+
+import com.fasterxml.jackson.annotation.JsonIdentityInfo;
+import com.fasterxml.jackson.annotation.JsonSubTypes;
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+
+@JsonTypeInfo(use = JsonTypeInfo.Id.NAME)
+@JsonSubTypes({
+        @JsonSubTypes.Type(value = RequiredAttendance.class, name = "required"),
+        @JsonSubTypes.Type(value = PreferredAttendance.class, name = "preferred"),
+})
+@JsonIdentityInfo(generator = JacksonUniqueIdGenerator.class)
 public abstract class Attendance extends AbstractPersistable {
 
     private Person person;

src/main/java/ai/timefold/solver/benchmarks/examples/meetingscheduling/domain/Day.java

@@ -5,7 +5,12 @@
 import java.util.Locale;
 
 import ai.timefold.solver.benchmarks.examples.common.domain.AbstractPersistable;
+import ai.timefold.solver.benchmarks.examples.common.persistence.jackson.JacksonUniqueIdGenerator;
 
+import com.fasterxml.jackson.annotation.JsonIdentityInfo;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+
+@JsonIdentityInfo(generator = JacksonUniqueIdGenerator.class)
 public class Day extends AbstractPersistable
         implements Comparable<Day> {
 
@@ -29,10 +34,12 @@ public void setDayOfYear(int dayOfYear) {
         this.dayOfYear = dayOfYear;
     }
 
+    @JsonIgnore
     public String getDateString() {
         return DAY_FORMATTER.format(toDate());
     }
 
+    @JsonIgnore
     public LocalDate toDate() {
         return LocalDate.ofYearDay(LocalDate.now().getYear(), dayOfYear);
     }

src/main/java/ai/timefold/solver/benchmarks/examples/meetingscheduling/domain/Meeting.java

@@ -3,13 +3,15 @@
 import java.util.List;
 
 import ai.timefold.solver.benchmarks.examples.common.domain.AbstractPersistable;
+import ai.timefold.solver.benchmarks.examples.common.persistence.jackson.JacksonUniqueIdGenerator;
 
+import com.fasterxml.jackson.annotation.JsonIdentityInfo;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+
+@JsonIdentityInfo(generator = JacksonUniqueIdGenerator.class)
 public class Meeting extends AbstractPersistable {
 
     private String topic;
-    private List<Person> speakerList;
-    private String content;
-    private boolean entireGroupMeeting;
     /**
      * Multiply by {@link TimeGrain#GRAIN_LENGTH_IN_MINUTES} to get duration in minutes.
      */
@@ -39,30 +41,6 @@ public void setTopic(String topic) {
         this.topic = topic;
     }
 
-    public List<Person> getSpeakerList() {
-        return speakerList;
-    }
-
-    public void setSpeakerList(List<Person> speakerList) {
-        this.speakerList = speakerList;
-    }
-
-    public String getContent() {
-        return content;
-    }
-
-    public void setContent(String content) {
-        this.content = content;
-    }
-
-    public boolean isEntireGroupMeeting() {
-        return entireGroupMeeting;
-    }
-
-    public void setEntireGroupMeeting(boolean entireGroupMeeting) {
-        this.entireGroupMeeting = entireGroupMeeting;
-    }
-
     public int getDurationInGrains() {
         return durationInGrains;
     }
@@ -91,18 +69,11 @@ public void setPreferredAttendanceList(List<PreferredAttendance> preferredAttend
     // Complex methods
     // ************************************************************************
 
+    @JsonIgnore
     public int getRequiredCapacity() {
         return requiredAttendanceList.size() + preferredAttendanceList.size();
     }
 
-    public String getDurationString() {
-        return (durationInGrains * TimeGrain.GRAIN_LENGTH_IN_MINUTES) + " minutes";
-    }
-
-    public String getLabel() {
-        return topic;
-    }
-
     @Override
     public String toString() {
         return topic;

src/main/java/ai/timefold/solver/benchmarks/examples/meetingscheduling/domain/MeetingAssignment.java

@@ -1,11 +1,16 @@
 package ai.timefold.solver.benchmarks.examples.meetingscheduling.domain;
 
 import ai.timefold.solver.benchmarks.examples.common.domain.AbstractPersistable;
+import ai.timefold.solver.benchmarks.examples.common.persistence.jackson.JacksonUniqueIdGenerator;
 import ai.timefold.solver.core.api.domain.entity.PlanningEntity;
 import ai.timefold.solver.core.api.domain.entity.PlanningPin;
 import ai.timefold.solver.core.api.domain.variable.PlanningVariable;
 
+import com.fasterxml.jackson.annotation.JsonIdentityInfo;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+
 @PlanningEntity
+@JsonIdentityInfo(generator = JacksonUniqueIdGenerator.class)
 public class MeetingAssignment extends AbstractPersistable {
 
     private Meeting meeting;
@@ -90,27 +95,31 @@ public int calculateOverlap(MeetingAssignment other) {
         return Math.min(end, otherEnd) - Math.max(start, otherStart);
     }
 
+    @JsonIgnore
     public Integer getLastTimeGrainIndex() {
         if (startingTimeGrain == null) {
             return null;
         }
         return startingTimeGrain.getGrainIndex() + meeting.getDurationInGrains() - 1;
     }
 
+    @JsonIgnore
     public String getStartingDateTimeString() {
         if (startingTimeGrain == null) {
             return null;
         }
         return startingTimeGrain.getDateTimeString();
     }
 
+    @JsonIgnore
     public int getRoomCapacity() {
         if (room == null) {
             return 0;
         }
         return room.getCapacity();
     }
 
+    @JsonIgnore
     public int getRequiredCapacity() {
         return meeting.getRequiredCapacity();
     }

src/main/java/ai/timefold/solver/benchmarks/examples/meetingscheduling/domain/Person.java

@@ -1,7 +1,11 @@
 package ai.timefold.solver.benchmarks.examples.meetingscheduling.domain;
 
 import ai.timefold.solver.benchmarks.examples.common.domain.AbstractPersistable;
+import ai.timefold.solver.benchmarks.examples.common.persistence.jackson.JacksonUniqueIdGenerator;
 
+import com.fasterxml.jackson.annotation.JsonIdentityInfo;
+
+@JsonIdentityInfo(generator = JacksonUniqueIdGenerator.class)
 public class Person extends AbstractPersistable {
 
     private String fullName;

src/main/java/ai/timefold/solver/benchmarks/examples/meetingscheduling/domain/Room.java

@@ -1,7 +1,11 @@
 package ai.timefold.solver.benchmarks.examples.meetingscheduling.domain;
 
 import ai.timefold.solver.benchmarks.examples.common.domain.AbstractPersistable;
+import ai.timefold.solver.benchmarks.examples.common.persistence.jackson.JacksonUniqueIdGenerator;
 
+import com.fasterxml.jackson.annotation.JsonIdentityInfo;
+
+@JsonIdentityInfo(generator = JacksonUniqueIdGenerator.class)
 public class Room extends AbstractPersistable {
 
     private String name;

src/main/java/ai/timefold/solver/benchmarks/examples/meetingscheduling/domain/TimeGrain.java

@@ -7,7 +7,12 @@
 import java.util.Objects;
 
 import ai.timefold.solver.benchmarks.examples.common.domain.AbstractPersistable;
+import ai.timefold.solver.benchmarks.examples.common.persistence.jackson.JacksonUniqueIdGenerator;
 
+import com.fasterxml.jackson.annotation.JsonIdentityInfo;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+
+@JsonIdentityInfo(generator = JacksonUniqueIdGenerator.class)
 public class TimeGrain extends AbstractPersistable
         implements Comparable<TimeGrain> {
 
@@ -57,25 +62,30 @@ public void setStartingMinuteOfDay(int startingMinuteOfDay) {
         this.startingMinuteOfDay = startingMinuteOfDay;
     }
 
+    @JsonIgnore
     public LocalDate getDate() {
         return day.toDate();
     }
 
+    @JsonIgnore
     public LocalTime getTime() {
         return LocalTime.of(startingMinuteOfDay / 60, startingMinuteOfDay % 60);
     }
 
+    @JsonIgnore
     public LocalDateTime getDateTime() {
         return LocalDateTime.of(getDate(), getTime());
     }
 
+    @JsonIgnore
     public String getTimeString() {
         int hourOfDay = startingMinuteOfDay / 60;
         int minuteOfHour = startingMinuteOfDay % 60;
         return (hourOfDay < 10 ? "0" : "") + hourOfDay
                 + ":" + (minuteOfHour < 10 ? "0" : "") + minuteOfHour;
     }
 
+    @JsonIgnore
     public String getDateTimeString() {
         return day.getDateString() + " " + getTimeString();
     }