Checkpoint - version of processes that pass a unit test - basic version of stateProviderInterface with memory & temp-file implementations

src/main/java/com/kingsrook/qqq/backend/core/actions/RunFunctionAction.java

@@ -21,6 +21,7 @@ import com.kingsrook.qqq.backend.core.model.metadata.processes.QFunctionInputMet
 import com.kingsrook.qqq.backend.core.model.metadata.processes.QFunctionMetaData;
 import com.kingsrook.qqq.backend.core.model.metadata.processes.QProcessMetaData;
 import com.kingsrook.qqq.backend.core.model.metadata.processes.QRecordListMetaData;
+import com.kingsrook.qqq.backend.core.utils.CollectionUtils;
 
 
 /*******************************************************************************
@@ -61,9 +62,7 @@ public class RunFunctionAction
       ////////////////////////////////////////////////////////////////////
       // load and run the user-defined code that actually does the work //
       ////////////////////////////////////////////////////////////////////
-      RunFunctionResult runFunctionResult = runFunctionBodyCode(function.getCode(), runFunctionRequest);
+      return (runFunctionBodyCode(function.getCode(), runFunctionRequest));
-
-      return (runFunctionResult);
    }
 
 
@@ -88,6 +87,8 @@ public class RunFunctionAction
          }
       }
 
+      if(!fieldsToGet.isEmpty())
+      {
          Map<String, Serializable> fieldValues = runFunctionRequest.getCallback().getFieldValues(fieldsToGet);
          for(Map.Entry<String, Serializable> entry : fieldValues.entrySet())
          {
@@ -95,6 +96,7 @@ public class RunFunctionAction
             // todo - check to make sure got values back?
          }
       }
+   }
 
 
 
@@ -108,7 +110,7 @@ public class RunFunctionAction
       QRecordListMetaData recordListMetaData = inputMetaData.getRecordListMetaData();
       if(recordListMetaData != null)
       {
-         if(runFunctionRequest.getRecords() == null)
+         if(CollectionUtils.nullSafeIsEmpty(runFunctionRequest.getRecords()))
          {
             QueryRequest queryRequest = new QueryRequest(runFunctionRequest.getInstance());
             queryRequest.setSession(runFunctionRequest.getSession());
@@ -133,18 +135,19 @@ public class RunFunctionAction
     *******************************************************************************/
    private RunFunctionResult runFunctionBodyCode(QCodeReference code, RunFunctionRequest runFunctionRequest)
    {
-      RunFunctionResult runFunctionResult;
+      RunFunctionResult runFunctionResult = new RunFunctionResult();
       try
       {
+         runFunctionResult.seedFromRequest(runFunctionRequest);
+
          Class<?> codeClass = Class.forName(code.getName());
          Object codeObject = codeClass.getConstructor().newInstance();
-         if(!(codeObject instanceof FunctionBody))
+         if(!(codeObject instanceof FunctionBody functionBodyCodeObject))
          {
             throw (new QException("The supplied code [" + codeClass.getName() + "] is not an instance of FunctionBody"));
          }
 
-         FunctionBody functionBodyCodeObject = (FunctionBody) codeObject;
+         functionBodyCodeObject.run(runFunctionRequest, runFunctionResult);
-         runFunctionResult = functionBodyCodeObject.run(runFunctionRequest);
       }
       catch(Exception e)
       {

src/main/java/com/kingsrook/qqq/backend/core/actions/RunProcessAction.java

@@ -7,12 +7,16 @@ package com.kingsrook.qqq.backend.core.actions;
 
 import java.util.List;
 import com.kingsrook.qqq.backend.core.exceptions.QException;
+import com.kingsrook.qqq.backend.core.model.actions.processes.ProcessState;
 import com.kingsrook.qqq.backend.core.model.actions.processes.RunFunctionRequest;
 import com.kingsrook.qqq.backend.core.model.actions.processes.RunFunctionResult;
 import com.kingsrook.qqq.backend.core.model.actions.processes.RunProcessRequest;
 import com.kingsrook.qqq.backend.core.model.actions.processes.RunProcessResult;
 import com.kingsrook.qqq.backend.core.model.metadata.processes.QFunctionMetaData;
 import com.kingsrook.qqq.backend.core.model.metadata.processes.QProcessMetaData;
+import com.kingsrook.qqq.backend.core.state.StateProviderInterface;
+import com.kingsrook.qqq.backend.core.state.TempFileStateProvider;
+import com.kingsrook.qqq.backend.core.state.UUIDStateKey;
 
 
 /*******************************************************************************
@@ -40,23 +44,67 @@ public class RunProcessAction
 
       RunProcessResult runProcessResult = new RunProcessResult();
 
+      UUIDStateKey stateKey = new UUIDStateKey();
+      RunFunctionResult lastFunctionResult = null;
+
       // todo - custom routing?
       List<QFunctionMetaData> functionList = process.getFunctionList();
       for(QFunctionMetaData function : functionList)
       {
          RunFunctionRequest runFunctionRequest = new RunFunctionRequest(runProcessRequest.getInstance());
+
+         if(lastFunctionResult != null)
+         {
+            loadState(stateKey, runFunctionRequest);
+         }
+
          runFunctionRequest.setProcessName(process.getName());
          runFunctionRequest.setFunctionName(function.getName());
-         // todo - how does this work again? runFunctionRequest.setCallback(?);
+         runFunctionRequest.setSession(runProcessRequest.getSession());
-         RunFunctionResult functionResult = new RunFunctionAction().execute(runFunctionRequest);
+         runFunctionRequest.setCallback(runProcessRequest.getCallback());
-         if(functionResult.getError() != null)
+         lastFunctionResult = new RunFunctionAction().execute(runFunctionRequest);
+         if(lastFunctionResult.getError() != null)
          {
-            runProcessResult.setError(functionResult.getError());
+            runProcessResult.setError(lastFunctionResult.getError());
             break;
          }
+
+         storeState(stateKey, lastFunctionResult);
+      }
+
+      if(lastFunctionResult != null)
+      {
+         runProcessResult.seedFromLastFunctionResult(lastFunctionResult);
       }
 
       return (runProcessResult);
    }
 
+
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   private StateProviderInterface getStateProvider()
+   {
+      // TODO - read this from somewhere in meta data eh?
+      // return InMemoryStateProvider.getInstance();
+      return TempFileStateProvider.getInstance();
+   }
+
+
+
+   private void storeState(UUIDStateKey stateKey, RunFunctionResult runFunctionResult)
+   {
+      getStateProvider().put(stateKey, runFunctionResult.getProcessState());
+   }
+
+
+
+   private void loadState(UUIDStateKey stateKey, RunFunctionRequest runFunctionRequest)
+   {
+      ProcessState processState = getStateProvider().get(ProcessState.class, stateKey);
+      runFunctionRequest.seedFromProcessState(processState);
+   }
+
 }

src/main/java/com/kingsrook/qqq/backend/core/interfaces/FunctionBody.java

@@ -17,5 +17,5 @@ public interface FunctionBody
    /*******************************************************************************
     ** TODO - document!
     *******************************************************************************/
-   RunFunctionResult run(RunFunctionRequest runFunctionRequest);
+   void run(RunFunctionRequest runFunctionRequest, RunFunctionResult runFunctionResult);
 }

src/main/java/com/kingsrook/qqq/backend/core/interfaces/mock/MockFunctionBody.java

@@ -18,16 +18,11 @@ import com.kingsrook.qqq.backend.core.model.actions.processes.RunFunctionResult;
 public class MockFunctionBody implements FunctionBody
 {
    @Override
-   public RunFunctionResult run(RunFunctionRequest runFunctionRequest)
+   public void run(RunFunctionRequest runFunctionRequest, RunFunctionResult runFunctionResult)
    {
-      RunFunctionResult runFunctionResult = new RunFunctionResult();
-      runFunctionResult.setRecords(runFunctionRequest.getRecords());
-
       runFunctionResult.getRecords().forEach(r -> r.setValue("mockValue", "Ha ha!"));
 
       runFunctionResult.setValues(runFunctionRequest.getValues());
       runFunctionResult.addValue("mockValue", "You so silly");
-
-      return (runFunctionResult);
    }
 }

src/main/java/com/kingsrook/qqq/backend/core/model/actions/processes/ProcessState.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright © 2021-2022. Kingsrook LLC <contact@kingsrook.com>.  All Rights Reserved.
+ */
+
+package com.kingsrook.qqq.backend.core.model.actions.processes;
+
+
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import com.kingsrook.qqq.backend.core.model.data.QRecord;
+
+
+/*******************************************************************************
+ **
+ *******************************************************************************/
+public class ProcessState implements Serializable
+{
+   private List<QRecord> records = new ArrayList<>();
+   private Map<String, Serializable> values = new HashMap<>();
+
+
+
+   /*******************************************************************************
+    ** Getter for records
+    **
+    *******************************************************************************/
+   public List<QRecord> getRecords()
+   {
+      return records;
+   }
+
+
+
+   /*******************************************************************************
+    ** Setter for records
+    **
+    *******************************************************************************/
+   public void setRecords(List<QRecord> records)
+   {
+      this.records = records;
+   }
+
+
+
+   /*******************************************************************************
+    ** Getter for values
+    **
+    *******************************************************************************/
+   public Map<String, Serializable> getValues()
+   {
+      return values;
+   }
+
+
+
+   /*******************************************************************************
+    ** Setter for values
+    **
+    *******************************************************************************/
+   public void setValues(Map<String, Serializable> values)
+   {
+      this.values = values;
+   }
+}

src/main/java/com/kingsrook/qqq/backend/core/model/actions/processes/RunFunctionRequest.java

@@ -6,7 +6,6 @@ package com.kingsrook.qqq.backend.core.model.actions.processes;
 
 
 import java.io.Serializable;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import com.kingsrook.qqq.backend.core.callbacks.QProcessCallback;
@@ -22,10 +21,9 @@ import com.kingsrook.qqq.backend.core.model.metadata.processes.QFunctionMetaData
  *******************************************************************************/
 public class RunFunctionRequest extends AbstractQRequest
 {
+   private ProcessState processState;
    private String processName;
    private String functionName;
-   private List<QRecord> records;
-   private Map<String, Serializable> values;
    private QProcessCallback callback;
 
 
@@ -35,6 +33,7 @@ public class RunFunctionRequest extends AbstractQRequest
     *******************************************************************************/
    public RunFunctionRequest()
    {
+      processState = new ProcessState();
    }
 
 
@@ -45,6 +44,19 @@ public class RunFunctionRequest extends AbstractQRequest
    public RunFunctionRequest(QInstance instance)
    {
       super(instance);
+      processState = new ProcessState();
+   }
+
+
+
+   /*******************************************************************************
+    ** e.g., for steps after the first step in a process, seed the data in a run
+    ** function request from a process state.
+    **
+    *******************************************************************************/
+   public void seedFromProcessState(ProcessState processState)
+   {
+      this.processState = processState;
    }
 
 
@@ -133,7 +145,7 @@ public class RunFunctionRequest extends AbstractQRequest
     *******************************************************************************/
    public List<QRecord> getRecords()
    {
-      return records;
+      return processState.getRecords();
    }
 
 
@@ -144,7 +156,7 @@ public class RunFunctionRequest extends AbstractQRequest
     *******************************************************************************/
    public void setRecords(List<QRecord> records)
    {
-      this.records = records;
+      this.processState.setRecords(records);
    }
 
 
@@ -155,7 +167,7 @@ public class RunFunctionRequest extends AbstractQRequest
     *******************************************************************************/
    public RunFunctionRequest withRecords(List<QRecord> records)
    {
-      this.records = records;
+      this.processState.setRecords(records);
       return (this);
    }
 
@@ -167,7 +179,7 @@ public class RunFunctionRequest extends AbstractQRequest
     *******************************************************************************/
    public Map<String, Serializable> getValues()
    {
-      return values;
+      return processState.getValues();
    }
 
 
@@ -178,7 +190,7 @@ public class RunFunctionRequest extends AbstractQRequest
     *******************************************************************************/
    public void setValues(Map<String, Serializable> values)
    {
-      this.values = values;
+      this.processState.setValues(values);
    }
 
 
@@ -189,7 +201,7 @@ public class RunFunctionRequest extends AbstractQRequest
     *******************************************************************************/
    public RunFunctionRequest withValues(Map<String, Serializable> values)
    {
-      this.values = values;
+      this.processState.setValues(values);
       return (this);
    }
 
@@ -201,11 +213,7 @@ public class RunFunctionRequest extends AbstractQRequest
     *******************************************************************************/
    public RunFunctionRequest addValue(String fieldName, Serializable value)
    {
-      if(this.values == null)
+      this.processState.getValues().put(fieldName, value);
-      {
-         this.values = new HashMap<>();
-      }
-      this.values.put(fieldName, value);
       return (this);
    }
 
@@ -251,11 +259,7 @@ public class RunFunctionRequest extends AbstractQRequest
     *******************************************************************************/
    public Serializable getValue(String fieldName)
    {
-      if(values == null)
+      return (processState.getValues().get(fieldName));
-      {
-         return (null);
-      }
-      return (values.get(fieldName));
    }
 
 
@@ -280,4 +284,15 @@ public class RunFunctionRequest extends AbstractQRequest
       return ((Integer) getValue(fieldName));
    }
 
+
+
+   /*******************************************************************************
+    ** Accessor for processState - protected, because we generally want to access
+    ** its members through wrapper methods, we think
+    **
+    *******************************************************************************/
+   protected ProcessState getProcessState()
+   {
+      return processState;
+   }
 }

src/main/java/com/kingsrook/qqq/backend/core/model/actions/processes/RunFunctionResult.java

@@ -6,7 +6,6 @@ package com.kingsrook.qqq.backend.core.model.actions.processes;
 
 
 import java.io.Serializable;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import com.kingsrook.qqq.backend.core.model.actions.AbstractQResult;
@@ -19,8 +18,7 @@ import com.kingsrook.qqq.backend.core.model.data.QRecord;
  *******************************************************************************/
 public class RunFunctionResult extends AbstractQResult
 {
-   private List<QRecord> records;
+   private ProcessState processState;
-   private Map<String, Serializable> values;
    private String error;
 
 
@@ -30,6 +28,18 @@ public class RunFunctionResult extends AbstractQResult
     *******************************************************************************/
    public RunFunctionResult()
    {
+      this.processState = new ProcessState();
+   }
+
+
+
+   /*******************************************************************************
+    ** e.g., populate the process state (records, values) in this result object.
+    **
+    *******************************************************************************/
+   public void seedFromRequest(RunFunctionRequest runFunctionRequest)
+   {
+      this.processState = runFunctionRequest.getProcessState();
    }
 
 
@@ -40,7 +50,7 @@ public class RunFunctionResult extends AbstractQResult
     *******************************************************************************/
    public List<QRecord> getRecords()
    {
-      return records;
+      return processState.getRecords();
    }
 
 
@@ -51,7 +61,7 @@ public class RunFunctionResult extends AbstractQResult
     *******************************************************************************/
    public void setRecords(List<QRecord> records)
    {
-      this.records = records;
+      this.processState.setRecords(records);
    }
 
 
@@ -62,7 +72,7 @@ public class RunFunctionResult extends AbstractQResult
     *******************************************************************************/
    public RunFunctionResult withRecords(List<QRecord> records)
    {
-      this.records = records;
+      this.processState.setRecords(records);
       return (this);
    }
 
@@ -74,7 +84,7 @@ public class RunFunctionResult extends AbstractQResult
     *******************************************************************************/
    public Map<String, Serializable> getValues()
    {
-      return values;
+      return processState.getValues();
    }
 
 
@@ -85,7 +95,7 @@ public class RunFunctionResult extends AbstractQResult
     *******************************************************************************/
    public void setValues(Map<String, Serializable> values)
    {
-      this.values = values;
+      this.processState.setValues(values);
    }
 
 
@@ -96,7 +106,7 @@ public class RunFunctionResult extends AbstractQResult
     *******************************************************************************/
    public RunFunctionResult withValues(Map<String, Serializable> values)
    {
-      this.values = values;
+      this.processState.setValues(values);
       return (this);
    }
 
@@ -108,11 +118,7 @@ public class RunFunctionResult extends AbstractQResult
     *******************************************************************************/
    public RunFunctionResult addValue(String fieldName, Serializable value)
    {
-      if(this.values == null)
+      this.processState.getValues().put(fieldName, value);
-      {
-         this.values = new HashMap<>();
-      }
-      this.values.put(fieldName, value);
       return (this);
    }
 
@@ -137,4 +143,15 @@ public class RunFunctionResult extends AbstractQResult
    {
       this.error = error;
    }
+
+
+
+   /*******************************************************************************
+    ** Accessor for processState
+    **
+    *******************************************************************************/
+   public ProcessState getProcessState()
+   {
+      return processState;
+   }
 }

src/main/java/com/kingsrook/qqq/backend/core/model/actions/processes/RunProcessResult.java

@@ -6,7 +6,6 @@ package com.kingsrook.qqq.backend.core.model.actions.processes;
 
 
 import java.io.Serializable;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import com.kingsrook.qqq.backend.core.model.actions.AbstractQResult;
@@ -19,8 +18,7 @@ import com.kingsrook.qqq.backend.core.model.data.QRecord;
  *******************************************************************************/
 public class RunProcessResult extends AbstractQResult
 {
-   private List<QRecord> records;
+   private ProcessState processState;
-   private Map<String, Serializable> values;
    private String error;
 
 
@@ -30,6 +28,19 @@ public class RunProcessResult extends AbstractQResult
     *******************************************************************************/
    public RunProcessResult()
    {
+      processState = new ProcessState();
+   }
+
+
+
+   /*******************************************************************************
+    ** e.g., populate the process state (records, values) in this result object from
+    ** the final function result
+    **
+    *******************************************************************************/
+   public void seedFromLastFunctionResult(RunFunctionResult runFunctionResult)
+   {
+      this.processState = runFunctionResult.getProcessState();
    }
 
 
@@ -40,7 +51,7 @@ public class RunProcessResult extends AbstractQResult
     *******************************************************************************/
    public List<QRecord> getRecords()
    {
-      return records;
+      return processState.getRecords();
    }
 
 
@@ -51,7 +62,7 @@ public class RunProcessResult extends AbstractQResult
     *******************************************************************************/
    public void setRecords(List<QRecord> records)
    {
-      this.records = records;
+      this.processState.setRecords(records);
    }
 
 
@@ -62,7 +73,7 @@ public class RunProcessResult extends AbstractQResult
     *******************************************************************************/
    public RunProcessResult withRecords(List<QRecord> records)
    {
-      this.records = records;
+      this.processState.setRecords(records);
       return (this);
    }
 
@@ -74,7 +85,7 @@ public class RunProcessResult extends AbstractQResult
     *******************************************************************************/
    public Map<String, Serializable> getValues()
    {
-      return values;
+      return processState.getValues();
    }
 
 
@@ -85,7 +96,7 @@ public class RunProcessResult extends AbstractQResult
     *******************************************************************************/
    public void setValues(Map<String, Serializable> values)
    {
-      this.values = values;
+      this.processState.setValues(values);
    }
 
 
@@ -96,7 +107,7 @@ public class RunProcessResult extends AbstractQResult
     *******************************************************************************/
    public RunProcessResult withValues(Map<String, Serializable> values)
    {
-      this.values = values;
+      this.processState.setValues(values);
       return (this);
    }
 
@@ -108,11 +119,7 @@ public class RunProcessResult extends AbstractQResult
     *******************************************************************************/
    public RunProcessResult addValue(String fieldName, Serializable value)
    {
-      if(this.values == null)
+      this.processState.getValues().put(fieldName, value);
-      {
-         this.values = new HashMap<>();
-      }
-      this.values.put(fieldName, value);
       return (this);
    }
 

src/main/java/com/kingsrook/qqq/backend/core/model/data/QRecord.java

@@ -6,6 +6,7 @@ package com.kingsrook.qqq.backend.core.model.data;
 
 
 import java.io.Serializable;
+import java.time.LocalDate;
 import java.util.LinkedHashMap;
 import java.util.Map;
 
@@ -19,7 +20,7 @@ import java.util.Map;
  * "Display values" (e.g., labels for possible values, or formatted numbers
  * (e.g., quantities with commas)) are in the displayValues map.
  *******************************************************************************/
-public class QRecord
+public class QRecord implements Serializable
 {
    private String tableName;
    //x private Serializable primaryKey;
@@ -102,8 +103,6 @@ public class QRecord
       return (this);
    }
 
-
-
    //x /*******************************************************************************
    //x  ** Getter for primaryKey
    //x  **
@@ -113,8 +112,6 @@ public class QRecord
    //x    return primaryKey;
    //x }
 
-
-
    //x /*******************************************************************************
    //x  ** Setter for primaryKey
    //x  **
@@ -124,8 +121,6 @@ public class QRecord
    //x    this.primaryKey = primaryKey;
    //x }
 
-
-
    //x /*******************************************************************************
    //x  ** Setter for primaryKey
    //x  **
@@ -224,4 +219,15 @@ public class QRecord
       return ((Integer) values.get(fieldName));
    }
 
+
+
+   /*******************************************************************************
+    ** Getter for a single field's value
+    **
+    *******************************************************************************/
+   public LocalDate getValueDate(String fieldName)
+   {
+      return ((LocalDate) values.get(fieldName));
+   }
+
 }

src/main/java/com/kingsrook/qqq/backend/core/model/metadata/processes/QFunctionInputMetaData.java

@@ -17,7 +17,7 @@ import com.kingsrook.qqq.backend.core.model.metadata.QFieldMetaData;
 public class QFunctionInputMetaData
 {
    private QRecordListMetaData recordListMetaData;
-   private List<QFieldMetaData> fieldList;
+   private List<QFieldMetaData> fieldList = new ArrayList<>();
 
 
 

src/main/java/com/kingsrook/qqq/backend/core/model/metadata/processes/QRecordListMetaData.java

@@ -96,17 +96,6 @@ public class QRecordListMetaData
 
 
 
-   /*******************************************************************************
-    **
-    *******************************************************************************/
-   public QRecordListMetaData withFields(Map<String, QFieldMetaData> fields)
-   {
-      this.fields = fields;
-      return (this);
-   }
-
-
-
    /*******************************************************************************
     **
     *******************************************************************************/

src/main/java/com/kingsrook/qqq/backend/core/modules/mock/MockQueryAction.java

@@ -5,6 +5,11 @@
 package com.kingsrook.qqq.backend.core.modules.mock;
 
 
+import java.io.Serializable;
+import java.math.BigDecimal;
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.Month;
 import java.util.ArrayList;
 import java.util.List;
 import com.kingsrook.qqq.backend.core.exceptions.QException;
@@ -41,7 +46,20 @@ public class MockQueryAction implements QueryInterface
 
          for(String field : table.getFields().keySet())
          {
-            record.setValue(field, "1");
+            Serializable value = switch (table.getField(field).getType())
+            {
+               case STRING -> "Foo";
+               case INTEGER -> 42;
+               case DECIMAL -> new BigDecimal("3.14159");
+               case DATE -> LocalDate.of(1970, Month.JANUARY, 1);
+               case DATE_TIME -> LocalDateTime.of(1970, Month.JANUARY, 1, 0, 0);
+               case TEXT -> "Four score and seven years ago...";
+               case HTML -> "<b>BOLD</b>";
+               case PASSWORD -> "abc***234";
+               default -> throw new IllegalStateException("Unexpected value: " + table.getField(field).getType());
+            };
+
+            record.setValue(field, value);
          }
 
          return rs;

src/main/java/com/kingsrook/qqq/backend/core/state/AbstractStateKey.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright © 2021-2022. Kingsrook LLC <contact@kingsrook.com>.  All Rights Reserved.
+ */
+
+package com.kingsrook.qqq.backend.core.state;
+
+
+/*******************************************************************************
+ **
+ *******************************************************************************/
+public abstract class AbstractStateKey
+{
+
+   /*******************************************************************************
+    ** Require all state keys to implement the equals method
+    *
+    *******************************************************************************/
+   @Override
+   public abstract boolean equals(Object that);
+
+   /*******************************************************************************
+    ** Require all state keys to implement the hashCode method
+    *
+    *******************************************************************************/
+   @Override
+   public abstract int hashCode();
+
+   /*******************************************************************************
+    ** Require all state keys to implement the toString method
+    *
+    *******************************************************************************/
+   @Override
+   public abstract String toString();
+
+}

src/main/java/com/kingsrook/qqq/backend/core/state/InMemoryStateProvider.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright © 2021-2022. Kingsrook LLC <contact@kingsrook.com>.  All Rights Reserved.
+ */
+
+package com.kingsrook.qqq.backend.core.state;
+
+
+import java.io.Serializable;
+import java.util.HashMap;
+import java.util.Map;
+
+
+/*******************************************************************************
+ ** Singleton class that provides a (non-persistent!!) in-memory state provider.
+ *******************************************************************************/
+public class InMemoryStateProvider implements StateProviderInterface
+{
+   private static InMemoryStateProvider instance;
+
+   private final Map<AbstractStateKey, Object> map;
+
+
+
+   /*******************************************************************************
+    ** Private constructor for singleton.
+    *******************************************************************************/
+   private InMemoryStateProvider()
+   {
+      this.map = new HashMap<>();
+   }
+
+
+
+   /*******************************************************************************
+    ** Singleton accessor
+    *******************************************************************************/
+   public static InMemoryStateProvider getInstance()
+   {
+      if(instance == null)
+      {
+         instance = new InMemoryStateProvider();
+      }
+      return instance;
+   }
+
+
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   @Override
+   public <T extends Serializable> void put(AbstractStateKey key, T data)
+   {
+      map.put(key, data);
+   }
+
+
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   @Override
+   public <T extends Serializable> T get(Class<? extends T> type, AbstractStateKey key)
+   {
+      try
+      {
+         return type.cast(map.get(key));
+      }
+      catch(ClassCastException cce)
+      {
+         throw new RuntimeException("Stored state value could not be cast to desired type", cce);
+      }
+   }
+
+}

src/main/java/com/kingsrook/qqq/backend/core/state/StateProviderInterface.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright © 2021-2022. Kingsrook LLC <contact@kingsrook.com>.  All Rights Reserved.
+ */
+
+package com.kingsrook.qqq.backend.core.state;
+
+
+import java.io.Serializable;
+
+
+/*******************************************************************************
+ **
+ *******************************************************************************/
+public interface StateProviderInterface
+{
+
+   /*******************************************************************************
+    ** Put a block of data, under a key, into the state store.
+    *******************************************************************************/
+   <T extends Serializable> void put(AbstractStateKey key, T data);
+
+   /*******************************************************************************
+    ** Get a block of data, under a key, from the state store.
+    *******************************************************************************/
+   <T extends Serializable> T get(Class<? extends T> type, AbstractStateKey key);
+}

src/main/java/com/kingsrook/qqq/backend/core/state/TempFileStateProvider.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright © 2021-2022. Kingsrook LLC <contact@kingsrook.com>.  All Rights Reserved.
+ */
+
+package com.kingsrook.qqq.backend.core.state;
+
+
+import java.io.File;
+import java.io.IOException;
+import java.io.Serializable;
+import com.kingsrook.qqq.backend.core.utils.JsonUtils;
+import org.apache.commons.io.FileUtils;
+
+
+/*******************************************************************************
+ ** Singleton class that provides a (non-persistent!!) in-memory state provider.
+ *******************************************************************************/
+public class TempFileStateProvider implements StateProviderInterface
+{
+   private static TempFileStateProvider instance;
+
+
+
+   /*******************************************************************************
+    ** Private constructor for singleton.
+    *******************************************************************************/
+   private TempFileStateProvider()
+   {
+   }
+
+
+
+   /*******************************************************************************
+    ** Singleton accessor
+    *******************************************************************************/
+   public static TempFileStateProvider getInstance()
+   {
+      if(instance == null)
+      {
+         instance = new TempFileStateProvider();
+      }
+      return instance;
+   }
+
+
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   @Override
+   public <T extends Serializable> void put(AbstractStateKey key, T data)
+   {
+      try
+      {
+         String json = JsonUtils.toJson(data);
+         FileUtils.writeStringToFile(new File("/tmp/" + key.toString()), json);
+      }
+      catch(IOException e)
+      {
+         // todo better
+         e.printStackTrace();
+      }
+   }
+
+
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   @Override
+   public <T extends Serializable> T get(Class<? extends T> type, AbstractStateKey key)
+   {
+      try
+      {
+         String json = FileUtils.readFileToString(new File("/tmp/" + key.toString()));
+         return JsonUtils.toObject(json, type);
+      }
+      catch(ClassCastException cce)
+      {
+         throw new RuntimeException("Stored state value could not be cast to desired type", cce);
+      }
+      catch(IOException ie)
+      {
+         throw new RuntimeException("Error loading state from file", ie);
+      }
+   }
+
+}

src/main/java/com/kingsrook/qqq/backend/core/state/UUIDStateKey.java

@@ -0,0 +1,95 @@
+/*
+ * Copyright © 2021-2022. Kingsrook LLC <contact@kingsrook.com>.  All Rights Reserved.
+ */
+
+package com.kingsrook.qqq.backend.core.state;
+
+
+import java.util.Objects;
+import java.util.UUID;
+
+
+/*******************************************************************************
+ **
+ *******************************************************************************/
+public class UUIDStateKey extends AbstractStateKey
+{
+   private final UUID uuid;
+
+
+
+   /*******************************************************************************
+    ** Default constructor - assigns a random UUID.
+    **
+    *******************************************************************************/
+   public UUIDStateKey()
+   {
+      uuid = UUID.randomUUID();
+   }
+
+
+
+   /*******************************************************************************
+    ** Constructor that lets you supply a UUID.
+    **
+    *******************************************************************************/
+   public UUIDStateKey(UUID uuid)
+   {
+      this.uuid = uuid;
+   }
+
+
+
+   /*******************************************************************************
+    ** Getter for uuid
+    **
+    *******************************************************************************/
+   public UUID getUuid()
+   {
+      return uuid;
+   }
+
+
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   @Override
+   public boolean equals(Object o)
+   {
+      if(this == o)
+      {
+         return true;
+      }
+
+      if(o == null || getClass() != o.getClass())
+      {
+         return false;
+      }
+
+      UUIDStateKey that = (UUIDStateKey) o;
+      return Objects.equals(uuid, that.uuid);
+   }
+
+
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   @Override
+   public int hashCode()
+   {
+      return Objects.hash(uuid);
+   }
+
+
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   @Override
+   public String toString()
+   {
+      return uuid.toString();
+   }
+}

src/test/java/com/kingsrook/qqq/backend/core/actions/RunProcessTest.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright © 2021-2021. Kingsrook LLC <contact@kingsrook.com>.  All Rights Reserved.
+ */
+
+package com.kingsrook.qqq.backend.core.actions;
+
+
+import java.io.Serializable;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import com.kingsrook.qqq.backend.core.callbacks.QProcessCallback;
+import com.kingsrook.qqq.backend.core.exceptions.QException;
+import com.kingsrook.qqq.backend.core.model.actions.processes.RunProcessRequest;
+import com.kingsrook.qqq.backend.core.model.actions.processes.RunProcessResult;
+import com.kingsrook.qqq.backend.core.model.actions.query.QQueryFilter;
+import com.kingsrook.qqq.backend.core.model.metadata.QFieldMetaData;
+import com.kingsrook.qqq.backend.core.utils.TestUtils;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+
+/*******************************************************************************
+ **
+ *******************************************************************************/
+public class RunProcessTest
+{
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   @Test
+   public void test() throws QException
+   {
+      TestCallback callback = new TestCallback();
+      RunProcessRequest request = new RunProcessRequest(TestUtils.defineInstance());
+      request.setSession(TestUtils.getMockSession());
+      request.setProcessName("addToPeoplesAge");
+      request.setCallback(callback);
+      RunProcessResult result = new RunProcessAction().execute(request);
+      assertNotNull(result);
+      assertNull(result.getError());
+      assertTrue(result.getRecords().stream().allMatch(r -> r.getValues().containsKey("age")), "records should have a value set by the process");
+      assertTrue(result.getValues().containsKey("maxAge"), "process result object should have a value set by the first function in the process");
+      assertTrue(result.getValues().containsKey("totalYearsAdded"), "process result object should have a value set by the second function in the process");
+      assertTrue(callback.wasCalledForQueryFilter, "callback was used for query filter");
+      assertTrue(callback.wasCalledForFieldValues, "callback was used for field values");
+   }
+
+
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   private static class TestCallback implements QProcessCallback
+   {
+      private boolean wasCalledForQueryFilter = false;
+      private boolean wasCalledForFieldValues = false;
+
+      /*******************************************************************************
+       **
+       *******************************************************************************/
+      @Override
+      public QQueryFilter getQueryFilter()
+      {
+         wasCalledForQueryFilter = true;
+         return (new QQueryFilter());
+      }
+
+
+
+      /*******************************************************************************
+       **
+       *******************************************************************************/
+      @Override
+      public Map<String, Serializable> getFieldValues(List<QFieldMetaData> fields)
+      {
+         wasCalledForFieldValues = true;
+         Map<String, Serializable> rs = new HashMap<>();
+         if (fields.stream().anyMatch(f -> f.getName().equals("yearsToAdd")))
+         {
+            rs.put("yearsToAdd", 42);
+         }
+         return (rs);
+      }
+   }
+}

src/test/java/com/kingsrook/qqq/backend/core/actions/processes/person/addtopeoplesage/AddAge.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright © 2021-2022. Kingsrook LLC <contact@kingsrook.com>.  All Rights Reserved.
+ */
+
+package com.kingsrook.qqq.backend.core.actions.processes.person.addtopeoplesage;
+
+
+import com.kingsrook.qqq.backend.core.interfaces.FunctionBody;
+import com.kingsrook.qqq.backend.core.model.actions.processes.RunFunctionRequest;
+import com.kingsrook.qqq.backend.core.model.actions.processes.RunFunctionResult;
+import com.kingsrook.qqq.backend.core.model.data.QRecord;
+
+
+/*******************************************************************************
+ **
+ *******************************************************************************/
+public class AddAge implements FunctionBody
+{
+   @Override
+   public void run(RunFunctionRequest runFunctionRequest, RunFunctionResult runFunctionResult)
+   {
+      int totalYearsAdded = 0;
+      Integer yearsToAdd = runFunctionRequest.getValueInteger("yearsToAdd");
+      for(QRecord record : runFunctionRequest.getRecords())
+      {
+         Integer age = record.getValueInteger("age");
+         age += yearsToAdd;
+         totalYearsAdded += yearsToAdd;
+         record.setValue("age", age);
+      }
+      runFunctionResult.addValue("totalYearsAdded", totalYearsAdded);
+   }
+}

src/test/java/com/kingsrook/qqq/backend/core/actions/processes/person/addtopeoplesage/GetAgeStatistics.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright © 2021-2022. Kingsrook LLC <contact@kingsrook.com>.  All Rights Reserved.
+ */
+
+package com.kingsrook.qqq.backend.core.actions.processes.person.addtopeoplesage;
+
+
+import java.time.LocalDate;
+import java.time.Period;
+import com.kingsrook.qqq.backend.core.interfaces.FunctionBody;
+import com.kingsrook.qqq.backend.core.model.actions.processes.RunFunctionRequest;
+import com.kingsrook.qqq.backend.core.model.actions.processes.RunFunctionResult;
+import com.kingsrook.qqq.backend.core.model.data.QRecord;
+
+
+/*******************************************************************************
+ **
+ *******************************************************************************/
+public class GetAgeStatistics implements FunctionBody
+{
+   @Override
+   public void run(RunFunctionRequest runFunctionRequest, RunFunctionResult runFunctionResult)
+   {
+      Integer min = null;
+      Integer max = null;
+      LocalDate now = LocalDate.now();
+      for(QRecord record : runFunctionRequest.getRecords())
+      {
+         LocalDate birthDate = record.getValueDate("birthDate");
+         Period until = birthDate.until(now);
+         int age = until.getYears();
+         record.setValue("age", age);
+         System.out.println(birthDate + " -> " + age);
+         min = (min == null || age < min) ? age : min;
+         max = (max == null || age > max) ? age : max;
+      }
+
+      runFunctionResult.addValue("minAge", min);
+      runFunctionResult.addValue("maxAge", max);
+   }
+}

src/test/java/com/kingsrook/qqq/backend/core/utils/TestUtils.java

@@ -46,6 +46,7 @@ public class TestUtils
       qInstance.addTable(defineTablePerson());
       qInstance.addPossibleValueSource(defineStatesPossibleValueSource());
       qInstance.addProcess(defineProcessGreetPeople());
+      qInstance.addProcess(defineProcessAddToPeoplesAge());
       return (qInstance);
    }
 
@@ -146,6 +147,53 @@ public class TestUtils
 
 
 
+   /*******************************************************************************
+    ** Define the "add to people's age" process
+    **
+    ** Works on a list of rows from the person table.
+    ** - first function reports the current min & max age for all input rows.
+    ** - user is then prompted for how much they want to add to everyone.
+    ** - then the second function adds that value to their age, and shows the results.
+    *******************************************************************************/
+   private static QProcessMetaData defineProcessAddToPeoplesAge()
+   {
+      return new QProcessMetaData()
+         .withName("addToPeoplesAge")
+         .withTableName("person")
+         .addFunction(new QFunctionMetaData()
+            .withName("getAgeStatistics")
+            .withCode(new QCodeReference()
+               .withName("com.kingsrook.qqq.backend.core.actions.processes.person.addtopeoplesage.GetAgeStatistics")
+               .withCodeType(QCodeType.JAVA)
+               .withCodeUsage(QCodeUsage.FUNCTION))
+            .withInputData(new QFunctionInputMetaData()
+               .withRecordListMetaData(new QRecordListMetaData().withTableName("person")))
+            .withOutputMetaData(new QFunctionOutputMetaData()
+               .withRecordListMetaData(new QRecordListMetaData()
+                  .withTableName("person")
+                  .addField(new QFieldMetaData("age", QFieldType.INTEGER)))
+               .withFieldList(List.of(
+                  new QFieldMetaData("minAge", QFieldType.INTEGER),
+                  new QFieldMetaData("maxAge", QFieldType.INTEGER))))
+            .withOutputView(new QOutputView()
+               .withMessageField("outputMessage"))) // todo - wut?
+         .addFunction(new QFunctionMetaData()
+            .withName("addAge")
+            .withCode(new QCodeReference()
+               .withName("com.kingsrook.qqq.backend.core.actions.processes.person.addtopeoplesage.AddAge")
+               .withCodeType(QCodeType.JAVA)
+               .withCodeUsage(QCodeUsage.FUNCTION))
+            .withInputData(new QFunctionInputMetaData()
+               .withFieldList(List.of(new QFieldMetaData("yearsToAdd", QFieldType.INTEGER))))
+            .withOutputMetaData(new QFunctionOutputMetaData()
+               .withRecordListMetaData(new QRecordListMetaData()
+                  .withTableName("person")
+                  .addField(new QFieldMetaData("newAge", QFieldType.INTEGER)))));
+
+   }
+
+
+
    /*******************************************************************************
     **
     *******************************************************************************/