Support custom serialization (#21)

* added the ability to add custom serialization

* added JacksonStateSerializer

* improved doc structure

* changed doc structure

* better doc

Author: sterlp

core/src/main/java/org/sterl/spring/persistent_tasks/api/TaskId.java

@@ -3,6 +3,8 @@
 import java.io.Serializable;
 import java.time.Duration;
 import java.time.OffsetDateTime;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
 import com.github.f4b6a3.uuid.UuidCreator;
 
@@ -13,6 +15,15 @@
  * Represents the ID of a persistentTask, which is currently not running.
  */
 public record TaskId<T extends Serializable>(String name) implements Serializable {
+    
+    @SuppressWarnings("rawtypes")
+    private static final Map<String, TaskId> CACHE = new ConcurrentHashMap<>();
+
+    @SuppressWarnings("unchecked")
+    public static <T extends Serializable> TaskId<T> of(String taskId) {
+        if (taskId == null || taskId.isBlank()) return null;
+        return CACHE.computeIfAbsent(taskId, s -> new TaskId<>(s));
+    }
 
     public TriggerBuilder<T> newTrigger() {
         return new TriggerBuilder<>(this);
@@ -36,11 +47,6 @@ public TriggerRequest<T> newUniqueTrigger(T state) {
                 .build();
     }
 
-    public static TaskId<Serializable> of(String taskId) {
-        if (taskId == null || taskId.isBlank()) return null;
-        return new TaskId<>(taskId);
-    }
-    
     @RequiredArgsConstructor(access = AccessLevel.PRIVATE)
     public static class TriggerBuilder<T extends Serializable> {
         private final TaskId<T> taskId;

core/src/main/java/org/sterl/spring/persistent_tasks/api/TriggerKey.java

@@ -31,10 +31,11 @@ public static TriggerKey of(@Nullable String id, TaskId<? extends Serializable>
         return new TriggerKey(id, taskId.name());
     }
 
-    public TaskId<Serializable> toTaskId() {
+    public <T extends Serializable> TaskId<T> toTaskId() {
         if (taskName == null) return null;
-        return new TaskId<>(taskName);
+        return TaskId.of(taskName);
     }
+
     /**
      * Builds a trigger for the given persistentTask name
      */

core/src/main/java/org/sterl/spring/persistent_tasks/api/task/JacksonStateSerializer.java

@@ -0,0 +1,44 @@
+package org.sterl.spring.persistent_tasks.api.task;
+
+import java.io.Serializable;
+
+import org.springframework.lang.NonNull;
+import org.sterl.spring.persistent_tasks.api.TaskId;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import lombok.RequiredArgsConstructor;
+
+/**
+ * Default implementation to use jackson instead java serialization for a task state.
+ * 
+ * @param <T> the type of the state for the deserialization
+ */
+@RequiredArgsConstructor
+public class JacksonStateSerializer<T extends Serializable> implements StateSerializer<T> {
+    
+    private final ObjectMapper mapper;
+    private final Class<T> clazz;
+
+    @Override
+    public byte[] serialize(@NonNull TaskId<T> id, @NonNull T obj) 
+        throws SerializationFailedException{
+
+        try {
+            return mapper.writeValueAsBytes(obj);
+        } catch (JsonProcessingException e) {
+            throw new SerializationFailedException(obj, e);
+        }
+    }
+
+    @Override
+    public T deserialize(@NonNull TaskId<T> id, @NonNull byte[] bytes)
+            throws DeSerializationFailedException {
+        try {
+            return mapper.readValue(bytes, clazz);
+        } catch (Exception e) {
+            throw new DeSerializationFailedException(bytes, e);
+        }
+    }
+}

core/src/main/java/org/sterl/spring/persistent_tasks/api/task/SerializationProvider.java

@@ -0,0 +1,14 @@
+package org.sterl.spring.persistent_tasks.api.task;
+
+import java.io.Serializable;
+
+/**
+ * /**
+ * Any task may provide an own serialization class.
+ * 
+ * @since 2.3.0
+ * @param <T> the type of the task state
+ */
+public interface SerializationProvider<T extends Serializable> {
+    StateSerializer<T> getSerializer();
+}

core/src/main/java/org/sterl/spring/persistent_tasks/api/task/StateSerializer.java

@@ -0,0 +1,36 @@
+package org.sterl.spring.persistent_tasks.api.task;
+
+import java.io.Serializable;
+
+import org.springframework.lang.NonNull;
+import org.sterl.spring.persistent_tasks.api.TaskId;
+import org.sterl.spring.persistent_tasks.exception.SpringPersistentTaskException;
+
+/**
+ * Interface for a state serialization of task.
+ * 
+ * @since 2.3.0
+ * @param <T> the state type
+ */
+public interface StateSerializer<T extends Serializable> {
+
+    byte[] serialize(@NonNull TaskId<T> id, @NonNull T obj) throws SerializationFailedException;
+
+    T deserialize(@NonNull TaskId<T> id, @NonNull byte[] bytes) throws DeSerializationFailedException;
+
+    class DeSerializationFailedException extends SpringPersistentTaskException {
+        private static final long serialVersionUID = 1L;
+
+        public DeSerializationFailedException(byte[] bytes, Exception e) {
+            super("Failed to deserialize state of length " + bytes.length, bytes, e);
+        }
+    }
+    
+    class SerializationFailedException extends SpringPersistentTaskException {
+        private static final long serialVersionUID = 1L;
+
+        public SerializationFailedException(Serializable obj, Exception e) {
+            super("Failed to serialize state " + obj.getClass(), obj, e);
+        }
+    }
+}

core/src/main/java/org/sterl/spring/persistent_tasks/config/SpringPersistentTasksConfig.java

@@ -1,18 +1,36 @@
 package org.sterl.spring.persistent_tasks.config;
 
+import java.io.Serializable;
+
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.boot.autoconfigure.AutoConfigurationPackage;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Role;
 import org.springframework.scheduling.annotation.EnableAsync;
 import org.springframework.scheduling.annotation.EnableScheduling;
 import org.sterl.spring.persistent_tasks.EnableSpringPersistentTasks;
+import org.sterl.spring.persistent_tasks.api.task.StateSerializer;
+import org.sterl.spring.persistent_tasks.trigger.component.DefaultStateSerializer;
+
+import lombok.extern.slf4j.Slf4j;
 
 @EnableScheduling
 @EnableAsync
 @AutoConfigurationPackage(basePackageClasses = EnableSpringPersistentTasks.class)
 @ComponentScan(basePackageClasses = EnableSpringPersistentTasks.class)
 @Role(BeanDefinition.ROLE_INFRASTRUCTURE)
+@Configuration
+@Slf4j
 public class SpringPersistentTasksConfig {
 
+    @Bean
+    @ConditionalOnMissingBean(DefaultStateSerializer.class)
+    StateSerializer<Serializable> defaultStateSerializer() {
+        log.info("Using java serialization for task states.", 
+                DefaultStateSerializer.class.getSimpleName());
+        return new DefaultStateSerializer();
+    }
 }

core/src/main/java/org/sterl/spring/persistent_tasks/history/api/FromCompletedTriggerEntityConverter.java

@@ -0,0 +1,26 @@
+package org.sterl.spring.persistent_tasks.history.api;
+
+import org.springframework.lang.NonNull;
+import org.springframework.stereotype.Component;
+import org.sterl.spring.persistent_tasks.api.Trigger;
+import org.sterl.spring.persistent_tasks.history.model.CompletedTriggerEntity;
+import org.sterl.spring.persistent_tasks.shared.ExtendetConvert;
+import org.sterl.spring.persistent_tasks.shared.converter.ToTrigger;
+
+import lombok.RequiredArgsConstructor;
+
+@Component
+@RequiredArgsConstructor
+public class FromCompletedTriggerEntityConverter implements ExtendetConvert<CompletedTriggerEntity, Trigger> {
+
+    private final ToTrigger toTrigger;
+
+    @NonNull
+    @Override
+    public Trigger convert(@NonNull CompletedTriggerEntity source) {
+        var result = toTrigger.convert(source);
+        result.setId(source.getId());
+        result.setInstanceId(source.getId());
+        return result;
+    }
+}

core/src/main/java/org/sterl/spring/persistent_tasks/history/api/HistoryConverter.java

@@ -2,28 +2,12 @@
 
 import org.springframework.lang.NonNull;
 import org.springframework.lang.Nullable;
-import org.sterl.spring.persistent_tasks.api.Trigger;
 import org.sterl.spring.persistent_tasks.api.HistoryTrigger;
-import org.sterl.spring.persistent_tasks.history.model.CompletedTriggerEntity;
 import org.sterl.spring.persistent_tasks.history.model.HistoryTriggerEntity;
 import org.sterl.spring.persistent_tasks.shared.ExtendetConvert;
-import org.sterl.spring.persistent_tasks.shared.converter.ToTrigger;
 
 interface HistoryConverter {
 
-    enum FromLastTriggerStateEntity implements ExtendetConvert<CompletedTriggerEntity, Trigger> {
-        INSTANCE;
-
-        @NonNull
-        @Override
-        public Trigger convert(@NonNull CompletedTriggerEntity source) {
-            var result = ToTrigger.INSTANCE.convert(source);
-            result.setId(source.getId());
-            result.setInstanceId(source.getId());
-            return result;
-        }
-    }
-    
     enum ToHistoryTrigger implements ExtendetConvert<HistoryTriggerEntity, HistoryTrigger> {
         INSTANCE;
 
@@ -41,6 +25,5 @@ public HistoryTrigger convert(@NonNull HistoryTriggerEntity source) {
             result.setStatus(source.getStatus());
             return result;
         }
-        
     }
 }

core/src/main/java/org/sterl/spring/persistent_tasks/history/api/TriggerHistoryResource.java

@@ -12,14 +12,13 @@
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
+import org.sterl.spring.persistent_tasks.api.HistoryTrigger;
 import org.sterl.spring.persistent_tasks.api.TaskStatusHistoryOverview;
 import org.sterl.spring.persistent_tasks.api.Trigger;
 import org.sterl.spring.persistent_tasks.api.TriggerGroup;
-import org.sterl.spring.persistent_tasks.api.HistoryTrigger;
 import org.sterl.spring.persistent_tasks.api.TriggerKey;
 import org.sterl.spring.persistent_tasks.api.TriggerSearch;
 import org.sterl.spring.persistent_tasks.history.HistoryService;
-import org.sterl.spring.persistent_tasks.history.api.HistoryConverter.FromLastTriggerStateEntity;
 import org.sterl.spring.persistent_tasks.history.api.HistoryConverter.ToHistoryTrigger;
 
 import lombok.RequiredArgsConstructor;
@@ -31,6 +30,7 @@ public class TriggerHistoryResource {
 
     public static final String PATH_GROUP = "history-grouped";
     private final HistoryService historyService;
+    private final FromCompletedTriggerEntityConverter converter;
 
     @GetMapping("history/instance/{instanceId}")
     public PagedModel<HistoryTrigger> listInstances(
@@ -56,7 +56,7 @@ public PagedModel<Trigger> list(
             TriggerSearch search,
             @PageableDefault(size = 100) Pageable page) {
 
-        return FromLastTriggerStateEntity.INSTANCE.toPage( //
+        return converter.toPage( //
                 historyService.searchTriggers(search, page));
     }
 

core/src/main/java/org/sterl/spring/persistent_tasks/shared/converter/ToTrigger.java

@@ -1,19 +1,22 @@
 package org.sterl.spring.persistent_tasks.shared.converter;
 
 import org.springframework.lang.NonNull;
+import org.springframework.stereotype.Component;
 import org.sterl.spring.persistent_tasks.api.Trigger;
 import org.sterl.spring.persistent_tasks.shared.ExtendetConvert;
 import org.sterl.spring.persistent_tasks.shared.model.HasTrigger;
 import org.sterl.spring.persistent_tasks.shared.model.TriggerEntity;
-import org.sterl.spring.persistent_tasks.trigger.component.StateSerializer;
+import org.sterl.spring.persistent_tasks.trigger.component.StateSerializationComponent;
 
+import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 
 @Slf4j
-public enum ToTrigger implements ExtendetConvert<HasTrigger, Trigger> {
-    INSTANCE;
-
-    private final static StateSerializer SERIALIZER = new StateSerializer();
+@Component
+@RequiredArgsConstructor
+public class ToTrigger implements ExtendetConvert<HasTrigger, Trigger> {
+    
+    private final StateSerializationComponent stateSerialization;
 
     @NonNull
     @Override
@@ -33,7 +36,7 @@ public Trigger convert(@NonNull HasTrigger hasData) {
         result.setRunningDurationInMs(source.getRunningDurationInMs());
         result.setStart(source.getStart());
         try {
-            result.setState(SERIALIZER.deserialize(source.getState()));
+            result.setState(stateSerialization.deserialize(source));
         } catch (Exception e) {
             var info = """
                     Failed to deserialize state