準備技術:

1. Vaadin
2. h2 Db
3. JPA container and implement

利用Vaadin提供的範例來實做一個JPA。

1. 先了解Vaadin對於JPA的流程和一般JPA不同，一般只要JPA implement就可以讓Servlet掛載，而Vaadin要有個container負責這種掛載。 下圖解釋我們需要的工具，我選的JPA是J2SE提供的，implement則是選Eclipse Link，Database是H2。

2. 整個專案的目錄與檔案如圖。

3. 

4. 首先處理資料庫部分，我利用POJO處理與資料庫欄位的對應並設Setter與 Getter，做了Person.Java與Department.Java，以下程式為部分。

   @Entity
   public class Department {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
   
    private String name;
   
    @OneToMany(mappedBy = "department")
    private Set<Person> persons;
   
    @Transient
    private Boolean superDepartment;
   
    @ManyToOne
    private Department parent;
   
    public Long getId() {
        return id;
    }
   
    public void setId(Long id) {
        this.id = id;
    }
   
    public String getName() {
        return name;
    }
   
    public void setName(String name) {
        this.name = name;
    }
   
    public Set<Person> getPersons() {
        return persons;
    }
   
    public void setPersons(Set<Person> persons) {
        this.persons = persons;
    }
   
    public Department getParent() {
        return parent;
    }
   
    public void setParent(Department parent) {
        this.parent = parent;
    }
   
    public boolean isSuperDepartment() {
        if (superDepartment == null) {
            superDepartment = getPersons().size() == 0;
        }
        return superDepartment;
    }
   
    @Transient
    public String getHierarchicalName() {
        if (parent != null) {
            return parent.toString() + " : " + name;
        }
        return name;
    }
   
    @Override
    public String toString() {
        return getHierarchicalName();
    }
   

   }

5. 在src目錄，我設META-INF目錄，撰寫persistence.xml 設置eclipse link JPA implement。

    <persistence-unit name="addressbook">
    	<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    	<exclude-unlisted-classes>false</exclude-unlisted-classes>
    	<properties>
    		<property name="eclipselink.jdbc.platform" value="org.eclipse.persistence.platform.database.H2Platform" />
    		<property name="eclipselink.jdbc.driver" value="org.h2.Driver" />
    		<property name="eclipselink.jdbc.url" value="jdbc:h2:tcp://localhost/~/test" />
    		<property name="eclipselink.jdbc.user" value="sa" />
    		<property name="eclipselink.jdbc.password" value="" />
    		<property name="eclipselink.logging.level" value="FINE" />
    		<property name="eclipselink.ddl-generation" value="drop-and-create-tables" />
    		<property name="eclipselink.ddl-generation.output-mode"  value="database" />
    	</properties>
    </persistence-unit>
   

6. 撰寫JPA container對應相關的Class。

   @SuppressWarnings("serial")
   public class HierarchicalDepartmentContainer extends JPAContainer {

    public HierarchicalDepartmentContainer() {
        super(Department.class);
        setEntityProvider(new CachingLocalEntityProvider<Department>(
                Department.class,
                JPAContainerFactory
                        .createEntityManagerForPersistenceUnit(JpaaddressbookUI.PERSISTENCE_UNIT)));
        setParentProperty("parent");
    }
   
    @Override
    public boolean areChildrenAllowed(Object itemId) {
        return super.areChildrenAllowed(itemId)
                && getItem(itemId).getEntity().isSuperDepartment();
    }
   

   }

7. 撰寫UI的設定

   @SuppressWarnings("serial")
   public class AddressBookMainView extends HorizontalSplitPanel implements
   ComponentContainer {

    private Tree groupTree;
   
    private Table personTable;
   
    private TextField searchField;
   
    private Button newButton;
    private Button deleteButton;
    private Button editButton;
   
    private JPAContainer<Department> departments;
    private JPAContainer<Person> persons;
   
    private Department departmentFilter;
    private String textFilter;
   
    public AddressBookMainView() {
        departments = new HierarchicalDepartmentContainer();
        persons = JPAContainerFactory.make(Person.class,
                JpaaddressbookUI.PERSISTENCE_UNIT);
        buildTree();
        buildMainArea();
   
        setSplitPosition(30);
    }
   
    @SuppressWarnings("deprecation")
    private void buildMainArea() {
        VerticalLayout verticalLayout = new VerticalLayout();
        setSecondComponent(verticalLayout);
   
        personTable = new Table(null, persons);
        personTable.setSelectable(true);
        personTable.setImmediate(true);
        personTable.addListener(new Property.ValueChangeListener() {
            @Override
            public void valueChange(ValueChangeEvent event) {
                setModificationsEnabled(event.getProperty().getValue() != null);
            }
   
            private void setModificationsEnabled(boolean b) {
                deleteButton.setEnabled(b);
                editButton.setEnabled(b);
            }
        });
   
        personTable.setSizeFull();
        // personTable.setSelectable(true);
        personTable.addListener(new ItemClickListener() {
            @Override
            public void itemClick(ItemClickEvent event) {
                if (event.isDoubleClick()) {
                    personTable.select(event.getItemId());
                }
            }
        });
   
        personTable.setVisibleColumns(new Object[] { "firstName", "lastName",
                "department", "phoneNumber", "street", "city", "zipCode" });
   
        HorizontalLayout toolbar = new HorizontalLayout();
        newButton = new Button("Add");
        newButton.addClickListener(new Button.ClickListener() {
   
            @Override
            public void buttonClick(ClickEvent event) {
                final BeanItem<Person> newPersonItem = new BeanItem<Person>(
                        new Person());
                PersonEditor personEditor = new PersonEditor(newPersonItem);
                personEditor.addListener(new EditorSavedListener() {
                    @Override
                    public void editorSaved(EditorSavedEvent event) {
                        persons.addEntity(newPersonItem.getBean());
                    }
                });
                UI.getCurrent().addWindow(personEditor);
            }
        });
   
        deleteButton = new Button("Delete");
        deleteButton.addClickListener(new Button.ClickListener() {
   
            @Override
            public void buttonClick(ClickEvent event) {
                persons.removeItem(personTable.getValue());
            }
        });
        deleteButton.setEnabled(false);
   
        editButton = new Button("Edit");
        editButton.addClickListener(new Button.ClickListener() {
   
            @Override
            public void buttonClick(ClickEvent event) {
                UI.getCurrent().addWindow(
                        new PersonEditor(personTable.getItem(personTable
                                .getValue())));
            }
        });
        editButton.setEnabled(false);
   
        searchField = new TextField();
        searchField.setInputPrompt("Search by name");
        searchField.addTextChangeListener(new TextChangeListener() {
   
            @Override
            public void textChange(TextChangeEvent event) {
                textFilter = event.getText();
                updateFilters();
            }
        });
   
        toolbar.addComponent(newButton);
        toolbar.addComponent(deleteButton);
        toolbar.addComponent(editButton);
        toolbar.addComponent(searchField);
        toolbar.setWidth("100%");
        toolbar.setExpandRatio(searchField, 1);
        toolbar.setComponentAlignment(searchField, Alignment.TOP_RIGHT);
   
        verticalLayout.addComponent(toolbar);
        verticalLayout.addComponent(personTable);
        verticalLayout.setExpandRatio(personTable, 1);
        verticalLayout.setSizeFull();
   
    }
   
    @SuppressWarnings("deprecation")
    private void buildTree() {
        groupTree = new Tree(null, departments);
        groupTree.setItemCaptionPropertyId("name");
   
        groupTree.setImmediate(true);
        groupTree.setSelectable(true);
        groupTree.addListener(new Property.ValueChangeListener() {
   
            @Override
            public void valueChange(ValueChangeEvent event) {
                Object id = event.getProperty().getValue();
                if (id != null) {
                    Department entity = departments.getItem(id).getEntity();
                    departmentFilter = entity;
                } else if (departmentFilter != null) {
                    departmentFilter = null;
                }
                updateFilters();
            }
   
        });
        setFirstComponent(groupTree);
    }
   
    private void updateFilters() {
        persons.setApplyFiltersImmediately(false);
        persons.removeAllContainerFilters();
        if (departmentFilter != null) {
            // two level hierarchy at max in our demo
            if (departmentFilter.getParent() == null) {
                persons.addContainerFilter(new Equal("department.parent",
                        departmentFilter));
            } else {
                persons.addContainerFilter(new Equal("department",
                        departmentFilter));
            }
        }
        if (textFilter != null && !textFilter.equals("")) {
            Or or = new Or(new Like("firstName", textFilter + "%", false),
                    new Like("lastName", textFilter + "%", false));
            persons.addContainerFilter(or);
        }
        persons.applyFilters();
    }
   

   }

8. 然後就可以deploy了。

參考資料

1. Vaadin 官網
2. Vaadin書籍

Day13 結束