Demonstration CSV Import functionaliy

.gitignore

@@ -0,0 +1,20 @@
+### Java template
+*.class
+
+# Mobile Tools for Java (J2ME)
+.mtj.tmp/
+
+# Package Files #
+*.jar
+*.war
+*.ear
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+# Created by .ignore support plugin (hsz.mobi)
+
+# Custom
+.idea/
+target/
+*.iml

README.md

@@ -10,9 +10,25 @@ own domain model. It also demonstrates a very simple add-on usage with Vaadin
 
 If you are new to Maven and want to try this application, check out this [tiny Maven tutorial](https://vaadin.com/blog/-/blogs/the-maven-essentials-for-the-impatient-developer).
 
-To get this running execute "mvn wildfly:run" to launch this locally on Wildfly 
-server or deploy to a Java EE 7+ server like Wildfly or Glassfish. With Liberty you'll need to 
-present a data source (other modern servers provide "development datasource" when 
+## Run the example
+
+As this application is based on JEE it relies on a JEE capable application server. 
+The Maven project setup includes a Wildfly Maven application server for demonstration purposes.
+
+To run the project, you can use
+
+```
+mvn wildfly:run
+```
+to launch this locally on Wildfly server. Afterwards, the application is available
+in your local browser at
+
+[http://localhost:8080/jpa-addressbook-1.0-SNAPSHOT](http://localhost:8080/jpa-addressbook-1.0-SNAPSHOT)
+
+
+Alternatively, you can deploy to a Java EE 7+ server like Wildfly or Glassfish. 
+With Liberty you'll need to present a data source 
+(other modern servers provide "development datasource" when 
 no jta-datasource is present in persistence.xml). 
 
 This is a suitable basis for small to medium sized apps. For larger applications,

phonebook_entries.csv

@@ -0,0 +1,3 @@
+name,number,email
+Martin Senne,+49 234 823 9178,martin@vaadin.com
+Marc Manager,+356 253 346 221,marc@coolcompany.com

phonebook_incorrect.csv

@@ -0,0 +1,4 @@
+a, b
+1, 2
+3, 4
+5, 6

pom.xml

@@ -16,6 +16,13 @@
     </properties>
 
     <dependencies>
+        <!-- CSV library -->
+        <dependency>
+            <groupId>com.opencsv</groupId>
+            <artifactId>opencsv</artifactId>
+            <version>3.3</version>
+        </dependency>
+
         <dependency>
             <groupId>org.apache.deltaspike.core</groupId>
             <artifactId>deltaspike-core-api</artifactId>

src/main/java/org/example/CSVImportView.java

@@ -0,0 +1,189 @@
+package org.example;
+
+import com.vaadin.cdi.CDIView;
+import com.vaadin.cdi.UIScoped;
+import com.vaadin.data.Container;
+import com.vaadin.data.util.IndexedContainer;
+import com.vaadin.navigator.View;
+import com.vaadin.navigator.ViewChangeListener;
+import com.vaadin.ui.*;
+import org.example.backend.PhoneBookEntry;
+import org.example.backend.PhoneBookService;
+import org.example.csv.CSVReadUtil;
+import org.example.ui.upload.FileBasedUploadReceptor;
+import org.vaadin.cdiviewmenu.ViewMenuItem;
+import org.vaadin.viritin.label.Header;
+import org.vaadin.viritin.layouts.MVerticalLayout;
+
+import javax.annotation.PostConstruct;
+import javax.inject.Inject;
+import java.io.*;
+import java.util.*;
+import java.util.function.Consumer;
+
+@UIScoped
+@CDIView("csv_imports")
+@ViewMenuItem(order = 2)
+public class CSVImportView extends MVerticalLayout implements View {
+
+    @Inject
+    PhoneBookService service;
+
+    Upload upload = new Upload();
+    Grid grid;
+    Button cancelButton;
+    Button saveButton;
+    Header header;
+
+    @PostConstruct
+    void init() {
+
+        header = new Header("CSV Import");
+
+        /**
+         * External handler, after upload was successful.
+         */
+        Consumer<FileBasedUploadReceptor.FileAndInfo> consumeReader = reader -> {
+            System.out.println(reader);
+            try {
+                IndexedContainer csvContainer = CSVReadUtil.buildContainerFromCSV(new FileReader(reader.getFile()));
+                // this is intentional, as attaching new datasource to existing grid seems cause problems in this Vaadin version
+                grid = new Grid();
+                grid.setWidth(100, Unit.PERCENTAGE);
+                grid.setContainerDataSource(csvContainer);
+                boolean columnNamesValid = checkEntries(grid.getContainerDataSource());
+                if ( !columnNamesValid ) {
+                    Notification.show("Save is not possible. Schema ( column names ) of CSV not correct.", Notification.Type.WARNING_MESSAGE);    
+                }
+                displayUploadedData( columnNamesValid );
+
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        };
+
+        FileBasedUploadReceptor fileBasedUploadReceptor = new FileBasedUploadReceptor(consumeReader);
+        upload.setReceiver(fileBasedUploadReceptor);
+        upload.addSucceededListener(fileBasedUploadReceptor);
+        upload.setImmediate(true);
+        upload.setButtonCaption("Upload CSV.");
+
+        saveButton = new Button("Save");
+        saveButton.addClickListener(clickEvent -> {
+            Container.Indexed container = grid.getContainerDataSource();
+            List<PhoneBookEntry> entries = createEntries(container);
+            saveEntries( entries );
+            Notification.show( entries.size() + " entries have been imported.");
+            displayUpload();
+        });
+
+        cancelButton = new Button("Cancel");
+        cancelButton.addClickListener(clickEvent -> {
+                    displayUpload();
+                }
+        );
+
+        displayUpload();
+    }
+
+    // ==========================================================
+    // ===== View related methods
+    // ==========================================================
+    public void displayUpload() {
+        removeAllComponents();
+
+        Label label = new Label("Please upload your CSV, that contains columns 'name', 'number' and 'email'");
+
+        addComponent(header);
+        addComponent(label);
+        addComponent(upload);
+    }
+
+    public void displayUploadedData( boolean activateSave ) {
+        removeAllComponents();
+
+        saveButton.setEnabled( activateSave );
+
+        HorizontalLayout hl = new HorizontalLayout();
+        hl.addComponent(cancelButton);
+        hl.addComponent(saveButton);
+
+        HorizontalLayout bottom = new HorizontalLayout();
+        bottom.setWidth(100, Unit.PERCENTAGE);
+        bottom.addComponent(hl);
+        bottom.setComponentAlignment(hl, Alignment.MIDDLE_RIGHT);
+
+        addComponent(header);
+        addComponent(grid);
+        setExpandRatio(grid, 1);
+        addComponent(bottom);
+    }
+
+    @Override
+    public void enter(ViewChangeListener.ViewChangeEvent event) {
+        // nothing to do on enter
+    }
+
+    // ==========================================================
+    // ===== Entry related methods
+    // ==========================================================
+    // TODO: To be moved to separate class, but left here to keep everything "close together".
+
+    private String NAME = "name";
+    private String NUMBER = "number";
+    private String EMAIL = "email";
+
+    /**
+     * Check if all property ids NAME, NUMBER and EMAIL are present in given container (as read from CSV).
+     * @param containerDataSource
+     * @return true if so
+     */
+    private boolean checkEntries(Container.Indexed containerDataSource) {
+        Collection<String> pids = (Collection<String>)containerDataSource.getContainerPropertyIds();
+
+        Set<String> actualSchema = new HashSet<>(pids);
+        Set<String> expectedSchema = new HashSet<>(Arrays.asList(NAME, NUMBER, EMAIL));
+
+        Set<String> intersect = (new HashSet<>(actualSchema));
+        intersect.retainAll(expectedSchema);
+
+        if (actualSchema.size() == 3) {
+            return true; // everything is fine
+        } else {
+            return false;
+        }
+    }
+
+    /**
+     * Create entries based on container content.
+     * 
+     * @param container use for construction of {@link PhoneBookEntry}s.
+     * @return list of entries
+     */
+    private List<PhoneBookEntry> createEntries(Container.Indexed container ) {
+
+        List<PhoneBookEntry> entries = new ArrayList<>();
+        int n = container.size();
+
+        // TODO: Introduce real mapping functionality
+        for ( Object itemId : container.getItemIds() ) {
+            String name = (String) container.getContainerProperty(itemId, NAME).getValue();
+            String number = (String) container.getContainerProperty(itemId, NUMBER).getValue();
+            String email = (String) container.getContainerProperty(itemId, EMAIL).getValue();
+            PhoneBookEntry entry = new PhoneBookEntry(name, number, email);
+            entries.add(entry);
+        }
+        return entries;
+    }
+
+    /**
+     * Persist given {@link PhoneBookEntry}s. 
+     * @param entries are the entries to persist.
+     */
+    private int saveEntries( List<PhoneBookEntry> entries ) {
+        for (PhoneBookEntry entry : entries) {
+            service.save(entry);
+        }
+        return entries.size();
+    }
+}

src/main/java/org/example/GroupsView.java

@@ -13,6 +13,7 @@
 import javax.inject.Inject;
 import org.example.backend.PhoneBookGroup;
 import org.example.backend.PhoneBookService;
+import org.vaadin.cdiviewmenu.ViewMenuItem;
 import org.vaadin.viritin.button.MButton;
 import org.vaadin.viritin.fields.MTable;
 import org.vaadin.viritin.fields.MTextField;
@@ -23,6 +24,7 @@
 
 @UIScoped
 @CDIView("groups")
+@ViewMenuItem(order = 1)
 public class GroupsView extends CssLayout implements View {
 
     @Inject