Add way of providing external instances without an existing file

PLUGINS.md

@@ -25,6 +25,7 @@ Inspect the `FormEntryModel` after finalization (or "post processing") and attac
 Inspect external instances (their ID and parsed XML) after parsing or provide custom parsers for specific instances or file types.
 
 ### API
+- `ExternalInstanceParser#addInstanceProvider`
 - `ExternalInstanceParser#addFileInstanceParser`
 
 The default `ExternalInstanceParser` can be overridden by creating an implementation of `ExternalInstanceParserFactory` and calling `XFormUtils.setExternalInstanceParserFactory` with it.

src/main/java/org/javarosa/core/model/instance/CsvExternalInstance.java

@@ -46,7 +46,7 @@ public TreeElement parse(@NotNull String instanceId, @NotNull String path) throw
     }
 
     @Override
-    public boolean isSupported(String instanceId, String instanceSrc) {
+    public boolean isSupported(@NotNull String instanceId, @NotNull String instanceSrc) {
         return instanceSrc.contains("file-csv");
     }
 

src/main/java/org/javarosa/core/model/instance/geojson/GeoJsonExternalInstance.java

@@ -74,7 +74,7 @@ public TreeElement parse(@NotNull String instanceId, @NotNull String path) throw
     }
 
     @Override
-    public boolean isSupported(String instanceId, String instanceSrc) {
+    public boolean isSupported(@NotNull String instanceId, @NotNull String instanceSrc) {
         return instanceSrc.endsWith("geojson");
     }
 }

src/main/java/org/javarosa/test/XFormsElement.java

@@ -44,7 +44,7 @@ static Map<String, String> parseAttributes(String name) {
         Map<String, String> attributes = new HashMap<>();
         String[] words = name.split(" ");
         for (String word : asList(words).subList(1, words.length)) {
-            String[] parts = word.split("(?<!\\))=(\"|')");
+            String[] parts = word.split("(?<!\\))=(\"|')", 2);
             attributes.put(parts[0], parts[1].substring(0, parts[1].length() - 1));
         }
         return attributes;

src/main/java/org/javarosa/xform/parse/ExternalInstanceParser.java

@@ -18,6 +18,7 @@
 import java.util.stream.Stream;
 
 import static java.util.Arrays.asList;
+import static java.util.Collections.emptyList;
 
 public class ExternalInstanceParser {
 
@@ -26,20 +27,30 @@ public class ExternalInstanceParser {
         new GeoJsonExternalInstance()
     );
 
-    public TreeElement parse(ReferenceManager referenceManager, String instanceId, String instanceSrc, boolean partial) throws IOException, UnfullfilledRequirementsException, InvalidStructureException, XmlPullParserException, InvalidReferenceException {
-        String path = getPath(referenceManager, instanceSrc);
+    private List<InstanceProvider> instanceProviders = emptyList();
 
-        Optional<FileInstanceParser> fileParser = fileInstanceParsers.stream()
-            .filter(fileInstanceParser -> fileInstanceParser.isSupported(instanceId, instanceSrc))
+    public TreeElement parse(ReferenceManager referenceManager, String instanceId, String instanceSrc, boolean partial) throws IOException, UnfullfilledRequirementsException, InvalidStructureException, XmlPullParserException, InvalidReferenceException {
+        Optional<InstanceProvider> instanceProvider = instanceProviders.stream()
+            .filter(parser -> parser.isSupported(instanceId, instanceSrc))
             .findFirst();
 
-        TreeElement root;
-        if (fileParser.isPresent()) {
-            root = fileParser.get().parse(instanceId, path, partial);
+        if (instanceProvider.isPresent()) {
+            return instanceProvider.get().get(instanceId, instanceSrc, partial);
         } else {
-            root = XmlExternalInstance.parse(instanceId, path);
+            String path = getPath(referenceManager, instanceSrc);
+
+            Optional<FileInstanceParser> fileParser = fileInstanceParsers.stream()
+                .filter(parser -> parser.isSupported(instanceId, instanceSrc))
+                .findFirst();
+
+            TreeElement root;
+            if (fileParser.isPresent()) {
+                root = fileParser.get().parse(instanceId, path, partial);
+            } else {
+                root = XmlExternalInstance.parse(instanceId, path);
+            }
+            return root;
         }
-        return root;
     }
 
     public TreeElement parse(ReferenceManager referenceManager, String instanceId, String instanceSrc) throws IOException, UnfullfilledRequirementsException, InvalidStructureException, XmlPullParserException, InvalidReferenceException {
@@ -57,6 +68,17 @@ public void addFileInstanceParser(FileInstanceParser fileInstanceParser) {
         ).collect(Collectors.toList());
     }
 
+    /**
+     * Adds {@link InstanceProvider} before others. The last added {@link InstanceProvider} will be checked
+     * (via {@link InstanceProvider#isSupported(String, String)}) first.
+     */
+    public void addInstanceProvider(InstanceProvider instanceProvider) {
+        instanceProviders = Stream.concat(
+            Stream.of(instanceProvider),
+            instanceProviders.stream()
+        ).collect(Collectors.toList());
+    }
+
     /**
      * Returns the path of the URI at srcLocation.
      *
@@ -75,6 +97,16 @@ default TreeElement parse(@NotNull String instanceId, @NotNull String path, bool
             return parse(instanceId, path);
         }
 
-        boolean isSupported(String instanceId, String instanceSrc);
+        boolean isSupported(@NotNull String instanceId, @NotNull String instanceSrc);
+    }
+
+    public interface InstanceProvider {
+        TreeElement get(@NotNull String instanceId, @NotNull String instanceSrc) throws IOException;
+
+        default TreeElement get(@NotNull String instanceId, @NotNull String instanceSrc, boolean partial) throws IOException {
+            return get(instanceId, instanceSrc);
+        }
+
+        boolean isSupported(@NotNull String instanceId, @NotNull String instanceSrc);
     }
 }

src/test/java/org/javarosa/plugins/InstancePluginTest.java

@@ -50,7 +50,61 @@ public void teardown() {
     }
 
     @Test
-    public void supportsPartialElements() throws IOException, XFormParser.ParseException {
+    public void instanceProvider_supportsPartialElements() throws IOException, XFormParser.ParseException {
+        externalInstanceParserFactory.setInstanceProvider(new FakeFileInstanceParser(asList(
+            new Pair<>("0", "Item 0"),
+            new Pair<>("1", "Item 1")
+        ), true));
+
+        File tempFile = TempFileUtils.createTempFile("fake-instance", "fake");
+        setUpSimpleReferenceManager(tempFile, "file-csv", "file");
+
+        Scenario scenario = Scenario.init("Fake instance form", html(
+                head(
+                    title("Fake instance form"),
+                    model(
+                        mainInstance(
+                            t("data id=\"fake-instance-form\"",
+                                t("question")
+                            )
+                        ),
+                        t("instance id=\"fake-instance\" src=\"jr://file-csv/fake-instance.fake\""),
+                        bind("/data/question").type("string")
+                    )
+                ),
+                body(
+                    select1Dynamic("/data/question", "instance('fake-instance')/root/item")
+                )
+            )
+        );
+
+        HashMap<String, DataInstance> instances = scenario.getFormDef().getFormInstances();
+        DataInstance fakeInstance = instances.get("fake-instance");
+        assertThat(fakeInstance.getRoot().getNumChildren(), equalTo(2));
+
+        TreeElement firstItem = (TreeElement) fakeInstance.getRoot().getChild("item", 0);
+        assertThat(firstItem.isPartial(), equalTo(true));
+        assertThat(firstItem.getNumChildren(), equalTo(2));
+        assertThat(firstItem.getChildAt(0).getName(), equalTo("value"));
+        assertThat(firstItem.getChildAt(0).getValue(), equalTo(null));
+        assertThat(firstItem.getChildAt(1).getName(), equalTo("label"));
+        assertThat(firstItem.getChildAt(1).getValue(), equalTo(null));
+
+        List<SelectChoice> selectChoices = scenario.choicesOf("/data/question");
+        assertThat(selectChoices.size(), equalTo(2));
+
+        assertThat(selectChoices.get(0).getValue(), equalTo("0"));
+        firstItem = (TreeElement) fakeInstance.getRoot().getChild("item", 0);
+        assertThat(firstItem.isPartial(), equalTo(false));
+        assertThat(firstItem.getNumChildren(), equalTo(2));
+        assertThat(firstItem.getChildAt(0).getName(), equalTo("value"));
+        assertThat(firstItem.getChildAt(0).getValue(), equalTo(new StringData("0")));
+        assertThat(firstItem.getChildAt(1).getName(), equalTo("label"));
+        assertThat(firstItem.getChildAt(1).getValue(), equalTo(new StringData("Item 0")));
+    }
+
+    @Test
+    public void fileInstanceParser_supportsPartialElements() throws IOException, XFormParser.ParseException {
         externalInstanceParserFactory.setFileInstanceParser(new FakeFileInstanceParser(asList(
             new Pair<>("0", "Item 0"),
             new Pair<>("1", "Item 1")
@@ -211,20 +265,33 @@ public void replacePartialElements_DoesNotOverrideNonPartialElements() throws IO
 
     private static class SwitchableExternalInstanceParserFactory implements ExternalInstanceParserFactory {
         private ExternalInstanceParser.FileInstanceParser fileInstanceParser;
+        private ExternalInstanceParser.InstanceProvider instanceProvider;
 
         @Override
         public ExternalInstanceParser getExternalInstanceParser() {
             ExternalInstanceParser externalInstanceParser = new ExternalInstanceParser();
-            externalInstanceParser.addFileInstanceParser(fileInstanceParser);
+
+            if (fileInstanceParser != null) {
+                externalInstanceParser.addFileInstanceParser(fileInstanceParser);
+            }
+
+            if (instanceProvider != null) {
+                externalInstanceParser.addInstanceProvider(instanceProvider);
+            }
+
             return externalInstanceParser;
         }
 
         public void setFileInstanceParser(ExternalInstanceParser.FileInstanceParser fileInstanceParser) {
             this.fileInstanceParser = fileInstanceParser;
         }
+
+        public void setInstanceProvider(ExternalInstanceParser.InstanceProvider instanceProvider) {
+            this.instanceProvider = instanceProvider;
+        }
     }
 
-    public static class FakeFileInstanceParser implements ExternalInstanceParser.FileInstanceParser {
+    public static class FakeFileInstanceParser implements ExternalInstanceParser.FileInstanceParser, ExternalInstanceParser.InstanceProvider {
 
         private final List<Pair<String, String>> items;
         private final boolean partialParse;
@@ -241,6 +308,25 @@ public TreeElement parse(@NotNull String instanceId, @NotNull String path) throw
 
         @Override
         public TreeElement parse(@NotNull String instanceId, @NotNull String path, boolean partial) throws IOException {
+            return createRoot(partial);
+        }
+
+        @Override
+        public TreeElement get(@NotNull String instanceId, @NotNull String instanceSrc) throws IOException {
+            return get(instanceId, instanceSrc, false);
+        }
+
+        @Override
+        public TreeElement get(@NotNull String instanceId, @NotNull String path, boolean partial) throws IOException {
+            return createRoot(partial);
+        }
+
+        @Override
+        public boolean isSupported(@NotNull String instanceId, @NotNull String instanceSrc) {
+            return instanceSrc.endsWith(".fake");
+        }
+
+        private @NotNull TreeElement createRoot(boolean partial) {
             boolean isPartial = partialParse && partial;
             TreeElement root = new TreeElement("root", 0);
 
@@ -262,10 +348,5 @@ public TreeElement parse(@NotNull String instanceId, @NotNull String path, boole
 
             return root;
         }
-
-        @Override
-        public boolean isSupported(String instanceId, String instanceSrc) {
-            return instanceSrc.endsWith(".fake");
-        }
     }
 }