Support Endpoints for Instance Datums

src/cli/java/org/commcare/util/screen/MultiSelectEntityScreen.java

@@ -9,6 +9,7 @@
 import org.commcare.core.interfaces.VirtualDataInstanceStorage;
 import org.commcare.data.xml.VirtualInstances;
 import org.commcare.modern.session.SessionWrapper;
+import org.commcare.modern.util.Pair;
 import org.commcare.session.CommCareSession;
 import org.commcare.suite.model.MultiSelectEntityDatum;
 import org.commcare.util.FormDataUtil;
@@ -80,7 +81,7 @@ public boolean autoSelectEntities(SessionWrapper session) {
             for (int i = 0; i < selectionSize; i++) {
                 evaluatedValues[i] = getReturnValueFromSelection(references.elementAt(i));
             }
-            processSelectionIntoInstance(evaluatedValues);
+            processSelectionIntoInstance(evaluatedValues, getNeededDatumId());
             updateSession(session);
             return true;
         }
@@ -134,9 +135,18 @@ private void prcessSelectionAsGuid(String guid) throws CommCareSessionException
                     "Could not make selection with reference id " + guid + " on this screen. " +
                             " If this error persists please report a bug to CommCareHQ.");
         }
+        validateEntitiesInInstance(cachedInstance);
         storageReferenceId = guid;
     }
 
+    private void validateEntitiesInInstance(ExternalDataInstance instance) throws CommCareSessionException {
+        AbstractTreeElement root = instance.getRoot();
+        for (int i = 0; i < root.getNumChildren(); i++) {
+            String entityVal = root.getChildAt(i).getValue().uncast().getString();
+            getAndValidateEntityReference(entityVal);
+        }
+    }
+
     private String getNeededDatumId() {
         return getSession().getNeededDatum().getDataId();
     }
@@ -147,7 +157,7 @@ private void processSelectedReferences(TreeReference[] selectedRefs) {
             for (int i = 0; i < selectedRefs.length; i++) {
                 evaluatedValues[i] = getReturnValueFromSelection(selectedRefs[i]);
             }
-            processSelectionIntoInstance(evaluatedValues);
+            processSelectionIntoInstance(evaluatedValues, getNeededDatumId());
         }
     }
 
@@ -156,29 +166,28 @@ private void processSelectedValues(String[] selectedValues)
         if (selectedValues != null && validateSelectionSize(selectedValues.length)) {
             String[] evaluatedValues = new String[selectedValues.length];
             for (int i = 0; i < selectedValues.length; i++) {
-                TreeReference currentReference = getEntityReference(selectedValues[i]);
-                if (currentReference == null) {
-                    throw new CommCareSessionException(
-                            "Could not select case " + selectedValues[i] + " on this screen. " +
-                                    " If this error persists please report a bug to CommCareHQ.");
-                }
+                TreeReference currentReference = getAndValidateEntityReference(selectedValues[i]);
                 evaluatedValues[i] = getReturnValueFromSelection(currentReference);
             }
-            processSelectionIntoInstance(evaluatedValues);
+            processSelectionIntoInstance(evaluatedValues, getNeededDatumId());
         }
     }
 
-    private void processSelectionIntoInstance(String[] evaluatedValues) {
-        ExternalDataInstance instance = VirtualInstances.buildSelectedValuesInstance(
-                getSession().getNeededDatum().getDataId(),
-                evaluatedValues);
-        String guid = virtualDataInstanceStorage.write(instance);
-        storageReferenceId = guid;
+    private TreeReference getAndValidateEntityReference(String selectedValue) throws CommCareSessionException {
+        TreeReference currentReference = getEntityReference(selectedValue);
+        if (currentReference == null) {
+            throw new CommCareSessionException(
+                    "Could not select case " + selectedValue + " on this screen. " +
+                            " If this error persists please report a bug to CommCareHQ.");
+        }
+        return currentReference;
+    }
 
-        // rebuild instance with the source
-        ExternalDataInstanceSource instanceSource = ExternalDataInstanceSource.buildVirtual(instance,
-                storageReferenceId);
-        selectedValuesInstance = instanceSource.toInstance();
+    private void processSelectionIntoInstance(String[] evaluatedValues, String instanceId) {
+        Pair<String, ExternalDataInstance> guidAndInstance = VirtualInstances.storeSelectedValuesInInstance(
+                virtualDataInstanceStorage, evaluatedValues, instanceId);
+        storageReferenceId = guidAndInstance.first;
+        selectedValuesInstance = guidAndInstance.second;
     }
 
     @Override

src/main/java/org/commcare/core/interfaces/RemoteInstanceFetcher.java

@@ -12,6 +12,8 @@ public interface RemoteInstanceFetcher {
     AbstractTreeElement getExternalRoot(String instanceId, ExternalDataInstanceSource source, String refId)
             throws RemoteInstanceException;
 
+    VirtualDataInstanceStorage getVirtualDataInstanceStorage();
+
     class RemoteInstanceException extends Exception {
 
         public RemoteInstanceException(String message) {

src/main/java/org/commcare/core/process/CommCareInstanceInitializer.java

@@ -6,10 +6,12 @@
 import org.commcare.cases.instance.CaseDataInstance;
 import org.commcare.cases.instance.CaseInstanceTreeElement;
 import org.commcare.cases.instance.LedgerInstanceTreeElement;
+import org.commcare.core.interfaces.RemoteInstanceFetcher;
 import org.commcare.core.interfaces.UserSandbox;
+import org.commcare.core.interfaces.VirtualDataInstanceStorage;
 import org.commcare.core.sandbox.SandboxUtils;
 import org.commcare.data.xml.VirtualInstances;
-import org.commcare.session.CommCareSession;
+import org.commcare.modern.session.SessionWrapper;
 import org.commcare.session.SessionFrame;
 import org.commcare.session.SessionInstanceBuilder;
 import org.commcare.suite.model.StackFrameStep;
@@ -37,7 +39,7 @@
  */
 public class CommCareInstanceInitializer extends InstanceInitializationFactory {
 
-    protected final CommCareSession session;
+    protected final SessionWrapper sessionWrapper;
     protected CaseInstanceTreeElement casebase;
     protected LedgerInstanceTreeElement stockbase;
     private final LocalCacheTable<String, TreeElement> fixtureBases = new LocalCacheTable<>();
@@ -54,16 +56,9 @@ public CommCareInstanceInitializer(UserSandbox sandbox) {
         this(null, sandbox, null);
     }
 
-    public CommCareInstanceInitializer(UserSandbox sandbox, CommCarePlatform platform) {
-        this(null, sandbox, platform);
-    }
-
-    public CommCareInstanceInitializer(UserSandbox sandbox, CommCareSession session) {
-        this(session, sandbox, null);
-    }
-
-    public CommCareInstanceInitializer(CommCareSession session, UserSandbox sandbox, CommCarePlatform platform) {
-        this.session = session;
+    public CommCareInstanceInitializer(SessionWrapper sessionWrapper, UserSandbox sandbox,
+            CommCarePlatform platform) {
+        this.sessionWrapper = sessionWrapper;
         this.mSandbox = sandbox;
         this.mPlatform = platform;
     }
@@ -92,13 +87,44 @@ public InstanceRoot generateRoot(ExternalDataInstance instance) {
         } else if (ref.startsWith(ExternalDataInstance.JR_REMOTE_REFERENCE)) {
             return setupExternalDataInstance(instance, ref, SessionFrame.STATE_QUERY_REQUEST);
         } else if (ref.startsWith(JR_SELECTED_ENTITIES_REFERENCE)) {
-            return setupExternalDataInstance(instance, ref, SessionFrame.STATE_MULTIPLE_DATUM_VAL);
+            return setupSelectedEntitiesInstance(instance, ref);
         } else if (ref.startsWith(JR_SEARCH_INPUT_REFERENCE)) {
             return setupExternalDataInstance(instance, ref, SessionFrame.STATE_QUERY_REQUEST);
         }
         return ConcreteInstanceRoot.NULL;
     }
 
+    private InstanceRoot setupSelectedEntitiesInstance(ExternalDataInstance instance, String ref) {
+        String stepType = SessionFrame.STATE_MULTIPLE_DATUM_VAL;
+        InstanceRoot instanceRoot = setupExternalDataInstance(instance, ref, stepType);
+        if (instanceRoot == ConcreteInstanceRoot.NULL) {
+            instanceRoot = getExternalDataInstanceSourceByStepValue(instance, stepType);
+        }
+        return instanceRoot;
+    }
+
+    // Tries to get instance by looking for the instance with id equal to the datum value in the storage
+    private InstanceRoot getExternalDataInstanceSourceByStepValue(ExternalDataInstance instance,
+            String stepType) {
+        RemoteInstanceFetcher instanceFetcher = sessionWrapper.getRemoteInstanceFetcher();
+        if (instanceFetcher != null) {
+            VirtualDataInstanceStorage instanceStorage = instanceFetcher.getVirtualDataInstanceStorage();
+            for (StackFrameStep step : sessionWrapper.getFrame().getSteps()) {
+                if (step.getType().equals(stepType)) {
+                    try {
+                        ExternalDataInstance loadedInstance = instanceStorage.read(step.getValue(),
+                                instance.getInstanceId(),
+                                instance.getReference());
+                        return new ConcreteInstanceRoot(loadedInstance.getRoot());
+                    } catch (VirtualInstances.InstanceNotFoundException e) {
+                        // continue looping
+                    }
+                }
+            }
+        }
+        return ConcreteInstanceRoot.NULL;
+    }
+
     /**
      * Initialises instances with reference to 'selected_cases'
      *
@@ -216,7 +242,7 @@ protected InstanceRoot setupSessionData(ExternalDataInstance instance) {
         }
         User u = mSandbox.getLoggedInUserUnsafe();
         TreeElement root =
-                SessionInstanceBuilder.getSessionInstance(session.getFrame(), getDeviceId(),
+                SessionInstanceBuilder.getSessionInstance(sessionWrapper.getFrame(), getDeviceId(),
                         getVersionString(), getCurrentDrift(), u.getUsername(), u.getUniqueId(),
                         u.getProperties());
         root.setParent(instance.getBase());
@@ -228,7 +254,7 @@ protected long getCurrentDrift() {
     }
 
     protected InstanceRoot getExternalDataInstanceSource(String reference, String stepType) {
-        for (StackFrameStep step : session.getFrame().getSteps()) {
+        for (StackFrameStep step : sessionWrapper.getFrame().getSteps()) {
             if (step.getType().equals(stepType) && step.hasDataInstanceSource(reference)) {
                 return step.getDataInstanceSource(reference);
             }
@@ -240,7 +266,7 @@ protected InstanceRoot getExternalDataInstanceSource(String reference, String st
      * Required for legacy instance support
      */
     protected InstanceRoot getExternalDataInstanceSourceById(String instanceId, String stepType) {
-        for (StackFrameStep step : session.getFrame().getSteps()) {
+        for (StackFrameStep step : sessionWrapper.getFrame().getSteps()) {
             if (step.getType().equals(stepType)) {
                 ExternalDataInstanceSource source = step.getDataInstanceSourceById(instanceId);
                 if (source != null) {

src/main/java/org/commcare/data/xml/VirtualInstances.java

@@ -6,7 +6,10 @@
 
 import com.google.common.collect.ImmutableMap;
 
+import org.commcare.core.interfaces.VirtualDataInstanceStorage;
+import org.commcare.modern.util.Pair;
 import org.javarosa.core.model.instance.ExternalDataInstance;
+import org.javarosa.core.model.instance.ExternalDataInstanceSource;
 import org.javarosa.core.model.instance.TreeElement;
 
 import java.util.ArrayList;
@@ -49,6 +52,27 @@ public static ExternalDataInstance buildSelectedValuesInstance(
         return new ExternalDataInstance(getSelectedEntitiesReference(instanceId), instanceId, root);
     }
 
+    /**
+     * Builds and stores the selected entitied into selected entities instance
+     *
+     * @param virtualDataInstanceStorage Instance Storage
+     * @param selectedValues             Values to be stored into instance
+     * @param instanceId                 instance id for the new instance
+     * @return A pair of unique storage id for the instance and the newly generated instance
+     */
+    public static Pair<String, ExternalDataInstance> storeSelectedValuesInInstance(
+            VirtualDataInstanceStorage virtualDataInstanceStorage, String[] selectedValues, String instanceId) {
+        ExternalDataInstance instance = VirtualInstances.buildSelectedValuesInstance(
+                instanceId,
+                selectedValues);
+        String guid = virtualDataInstanceStorage.write(instance);
+
+        // rebuild instance with the source
+        ExternalDataInstanceSource instanceSource = ExternalDataInstanceSource.buildVirtual(instance, guid);
+        ExternalDataInstance selectedValuesInstance = instanceSource.toInstance();
+        return new Pair<>(guid, selectedValuesInstance);
+    }
+
 
     public static String getSelectedEntitiesReference(String referenceId) {
         return getInstanceReference(JR_SELECTED_ENTITIES_REFERENCE, referenceId);
@@ -92,4 +116,18 @@ public static String getReferenceScheme(String reference) {
     public static String getInstanceReference(String referenceScheme, String referenceId) {
         return referenceScheme.concat("/").concat(referenceId);
     }
+
+    /**
+     * Throw when the data instance with the given key doesn't exist in the DB
+     */
+    public static class InstanceNotFoundException extends RuntimeException {
+
+        public InstanceNotFoundException(String key, String namespace) {
+            super(String.format(
+                    "Could not find data instance with ID %s (namespace=%s)." +
+                            "Redirecting to home screen. If this issue persists, please file a bug report.",
+                    key, namespace
+            ));
+        }
+    }
 }

src/main/java/org/commcare/modern/session/SessionWrapper.java

@@ -23,19 +23,33 @@ public class SessionWrapper extends CommCareSession implements SessionWrapperInt
     final protected UserSandbox mSandbox;
     final protected CommCarePlatform mPlatform;
     protected CommCareInstanceInitializer initializer;
+    protected RemoteInstanceFetcher remoteInstanceFetcher;
 
-    public SessionWrapper(CommCareSession session, CommCarePlatform platform, UserSandbox sandbox) {
-        this(platform, sandbox);
+    public SessionWrapper(CommCareSession session, CommCarePlatform platform, UserSandbox sandbox,
+            RemoteInstanceFetcher remoteInstanceFetcher) {
+        this(platform, sandbox, remoteInstanceFetcher);
         this.frame = session.getFrame();
         this.setFrameStack(session.getFrameStack());
     }
+
+
+    public SessionWrapper(CommCareSession session, CommCarePlatform platform, UserSandbox sandbox) {
+        this(session, platform, sandbox, null);
+    }
 
     public SessionWrapper(CommCarePlatform platform, UserSandbox sandbox) {
         super(platform);
         this.mSandbox = sandbox;
         this.mPlatform = platform;
     }
 
+    public SessionWrapper(CommCarePlatform platform, UserSandbox sandbox, RemoteInstanceFetcher remoteInstanceFetcher) {
+        super(platform);
+        this.mSandbox = sandbox;
+        this.mPlatform = platform;
+        this.remoteInstanceFetcher = remoteInstanceFetcher;
+    }
+
     /**
      * @return The evaluation context for the current state.
      */
@@ -72,7 +86,7 @@ public CommCareInstanceInitializer getIIF() {
         return initializer;
     }
 
-    public void prepareExternalSources(RemoteInstanceFetcher remoteInstanceFetcher) throws RemoteInstanceFetcher.RemoteInstanceException {
+    public void prepareExternalSources() throws RemoteInstanceFetcher.RemoteInstanceException {
         for(StackFrameStep step : frame.getSteps()) {
             step.initDataInstanceSources(remoteInstanceFetcher);
         }
@@ -101,4 +115,8 @@ public String getNeededData() {
     public void stepBack() {
         super.stepBack(getEvaluationContext());
     }
+
+    public RemoteInstanceFetcher getRemoteInstanceFetcher() {
+        return remoteInstanceFetcher;
+    }
 }

src/main/java/org/commcare/modern/session/SessionWrapperInterface.java

@@ -22,5 +22,5 @@ public interface SessionWrapperInterface {
     EvaluationContext getRestrictedEvaluationContext(String commandId, Set<String> instancesToInclude);
     EvaluationContext getEvaluationContextWithAccumulatedInstances(String commandID, XPathAnalyzable xPathAnalyzable);
 
-    void prepareExternalSources(RemoteInstanceFetcher fetcher) throws RemoteInstanceFetcher.RemoteInstanceException;
+    void prepareExternalSources() throws RemoteInstanceFetcher.RemoteInstanceException;
 }