After sorting List in ascending and descending order i want to invoke binarySearch method.
But it not working as i have implemented comparable.
class Student implements Comparable<Student>{
private int id;
private String name;
public Student(int id, String name){
this.id = id;
this.name = name;
}
public int getId(){
return id;
}
public String getName(){
return name;
}
#Override
public int compareTo(Student o) {
int j = o.getId();
int result = this.id - j;
return result;
}
}
public class CollectionSearchDemo {
public static void main(String[] args) {
List<Student> list = new ArrayList<Student>();
list.add(new Student(3, "ouier"));
list.add(new Student(2, "fdgds"));
list.add(new Student(7, "kiluf"));
list.add(new Student(1, "6trfd"));
list.add(new Student(8, "hjgas"));
list.add(new Student(5, "ewwew"));
Collections.sort(list, new Comparator<Student>() {
#Override
public int compare(Student arg0, Student arg1) {
return arg0.getId() - arg1.getId();
}
});
Iterator iterator = list.iterator();
while(iterator.hasNext()){
Student student = (Student) iterator.next();
System.out.print(student.getId()+":"+student.getName()+" ");
}
System.out.println("\nSorting in reverse order:");
// Collections.reverse(list);
Comparator<Student> collections = Collections.reverseOrder();
Collections.sort(list, collections);
Iterator iterator1 = list.iterator();
while(iterator1.hasNext()){
Student student = (Student) iterator1.next();
System.out.print(student.getId()+":"+student.getName()+" ");
}
System.out.println("I want to do searching ");
System.out.println("\n2 is at:"+Collections.binarySearch(list, 2, new Student()));
// facing exception at this line.I don't know what to use as argument of binarySearch() method.
}
}
I could have done this by implementing comparator but i have such requirement in my project
Please guide me.
From documentation of Collections.binarySearch:
The list must be sorted into ascending order according to the natural ordering of its elements (as by the sort(List) method) prior to making this call. If it is not sorted, the results are undefined.
Related
I am new to DynamoDB and wanted to know how can we query on a table in DynamoDB by using ONLY partition key in JAVA
I have table called "ervive-pdi-data-invalid-qa" and it's Schema is :
partition key is "SubmissionId"
Sort key is "Id".
City (Attribute)
Errors (Attribute)
The table looks like this:
Table
I want to retrieve the sort key value and remaining attributes data by using Partition key using (software.amazon.awssdk) new version of AWS SDK DynamoDB classes.
is it possible to get it? If so, can any one post the answers?
Have tried this:
DynamoDbClient ddb =
DynamoDbClient.builder().region(Region.US_EAST_1).build();
DynamoDbEnhancedClient enhancedClient =
DynamoDbEnhancedClient.builder()
.dynamoDbClient(ddb)
.build();
//Define table
DynamoDbTable<ErvivePdiDataInvalidQa> table =
enhancedClient.table("ervive-pdi-data-invalid-qa",
TableSchema.fromBean(ErvivePdiDataInvalidQa.class));
Key key = Key.builder().partitionValue(2023).build();
ErvivePdiDataInvalidQa result = table.getItem(r->r.key(key));
System.out.println("The record id is "+result.getId());
ErvivePdiDataInvalidQa table class is in below comment*
and it is returning "The provided key element does not match the schema (Service: DynamoDb, Status Code: 400, Request ID: PE1MKPMQ9MLT51OLJQVDCURQGBVV4KQNSO5AEMVJF66Q9ASUAAJG, Extended Request ID: null)"
Query you need is documented in one of the examples of AWS Dynamodb Query API for Java.
AmazonDynamoDB client = AmazonDynamoDBClientBuilder.standard()
.withRegion(Regions.US_WEST_2).build();
DynamoDB dynamoDB = new DynamoDB(client);
Table table = dynamoDB.getTable("ervive-pdi-data-invalid-qa");
QuerySpec spec = new QuerySpec()
.withKeyConditionExpression("SubmissionId = :v_id")
.withValueMap(new ValueMap()
.withInt(":v_id", 2146));
ItemCollection<QueryOutcome> items = table.query(spec);
Iterator<Item> iterator = items.iterator();
Item item = null;
while (iterator.hasNext()) {
item = iterator.next();
System.out.println(item.toJSONPretty());
}
A single Query operation can retrieve a maximum of 1 MB of data, see documentation
I have been working with Padma on this issue. We first tried A. Khan's code but could not get passed authentication with v1. Instead we got "WARNING: Your profile name includes a 'profile ' prefix. This is considered part of the profile name in the Java SDK, so you will need to include this prefix in your profile name when you reference this profile from your Java code."
ultimately it could not get the credentials. Our credentials assume IAM roles in .aws/config-i2 file. It works fine in v2 but not v1.
So then we tried v2 of the SDK and have no problems with connecting but we get NULL returned on trying to fetch all records from the table.
In all of the below attempts using v2 of SDK, table data returns NULL
We created this table class
package data;
import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbBean;
import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbPartitionKey;
import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbSortKey;
#DynamoDbBean
public class ErvivePdiDataInvalidQa {
private int submissionId;
private String id;
private String address1;
private String city;
private String dateOfBirth;
private String errors;
private String firstName;
private String firstNameNormalized;
private String gender;
private String lastName;
private String lastNameNormalized;
private String middleNameInitial;
private String postalCode;
private String rowNumber;
private String state;
private String submissionType;
#DynamoDbPartitionKey
public int getSubmissionId() {
return submissionId;
}
public void setSubmissionId(int submissionId) {
this.submissionId = submissionId;
}
#DynamoDbSortKey
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getAddress1() {
return address1;
}
public void setAddress1(String Address1) {
this.address1 = Address1;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getDateOfBirth() {
return dateOfBirth;
}
public void setDateOfBirth(String dateOfBirth) {
this.dateOfBirth = dateOfBirth;
}
public String getErrors() {
return errors;
}
public void setErrors(String errors) {
this.errors = errors;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getFirstNameNormalized() {
return firstNameNormalized;
}
public void setFirstNameNormalized(String firstNameNormalized) {
this.firstNameNormalized = firstNameNormalized;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getLastNameNormalized() {
return lastNameNormalized;
}
public void setLastNameNormalized(String lastNameNormalized) {
this.lastNameNormalized = lastNameNormalized;
}
public String getMiddleNameInitial() {
return middleNameInitial;
}
public void setMiddleNameInitial(String middleNameInitial) {
this.middleNameInitial = middleNameInitial;
}
public String getPostalCode() {
return postalCode;
}
public void setPostalCode(String postalCode) {
this.postalCode = postalCode;
}
public String getRowNumber() {
return rowNumber;
}
public void setRowNumber(String rowNumber) {
this.rowNumber = rowNumber;
}
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
public String getSubmissionType() {
return submissionType;
}
public void setSubmissionType(String submissionType) {
this.submissionType = submissionType;
}
}
DynamoDB code to get all records
//Connection
DynamoDbClient ddb = DynamoDbClient.builder().build();
DynamoDbEnhancedClient enhancedClient = DynamoDbEnhancedClient.builder()
.dynamoDbClient(ddb)
.build();
//Define table
DynamoDbTable<ErvivePdiDataInvalidQa> table = enhancedClient.table("ervive-pdi-data-invalid-qa", TableSchema.fromBean(ErvivePdiDataInvalidQa.class));
//Get All Items from table - RETURNING NULL
Iterator<ErvivePdiDataInvalidQa> results = table.scan().items().iterator();
while (results.hasNext()) {
ErvivePdiDataInvalidQa rec = results.next();
System.out.println("The record id is "+rec.getId());
}
Also tried:
DynamoDB code to filter by SubmissionID
AttributeValue attr = AttributeValue.builder()
.n("1175")
.build();
// Get only Open items in the Work table
Map<String, AttributeValue> myMap = new HashMap<>();
myMap.put(":val1", attr);
Map<String, String> myExMap = new HashMap<>();
myExMap.put("#sid", "SubmissionId");
// Set the Expression so only Closed items are queried from the Work table
Expression expression = Expression.builder()
.expressionValues(myMap)
.expressionNames(myExMap)
.expression("#sid = :val1")
.build();
ScanEnhancedRequest enhancedRequest = ScanEnhancedRequest.builder()
.filterExpression(expression)
.limit(15)
.build();
// Get items in the Record table and write out the ID value
Iterator<ErvivePdiDataInvalidQa> results = table.scan(enhancedRequest).items().iterator();
while (results.hasNext()) {
ErvivePdiDataInvalidQa record = results.next();
System.out.println("The record id is " + record.getId());
}
Is there any way I can display multiple components(like CheckBox, Label etc.) to a single cell of a Vaadin Grid? The Grid displays data populated dynamically by a GeneratedPropertyContainer.
Thanks in advance.
If you search the Vaadin directory you will find a few extensions, such as ComponentRenderer add-on which allow you to have such features in a somewhat painless way. Below you can see a code sample based on Vaadin v7.7.3 and v1.0.2 of the before-mentioned add-on. Please remember to update and recompile your widgetset.
public class GridWithMultiComponentRenderer extends VerticalLayout {
private static final String BUTTONS_ID = "buttons";
public GridWithMultiComponentRenderer() {
// basic grid setup
Grid grid = new Grid(new BeanItemContainer<>(Person.class));
grid.setSizeFull();
addComponent(grid);
// add the decorator
ComponentGridDecorator<Person> gridDecorator = new ComponentGridDecorator<>(grid, Person.class);
// generate the column which will display the components
gridDecorator.addComponentColumn(BUTTONS_ID, person -> new HorizontalLayout(
new Button("Get name", event -> Notification.show(person.getName())),
new Button("Get surname", event -> Notification.show(person.getSurname())),
new Button("Get age", event -> Notification.show(String.valueOf(person.getAge())))
));
// set column order
grid.setColumns("name", "surname", "age", BUTTONS_ID);
// add some dummy data
Random random = new Random();
for (int i = 0; i < 10; i++) {
gridDecorator.add(new Person("Name " + i, "Surname " + i, random.nextInt(99) + 1));
}
}
// POJO for simple binding
public static class Person {
private String name;
private String surname;
private int age;
public Person(String name, String surname, int age) {
this.name = name;
this.surname = surname;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSurname() {
return surname;
}
public void setSurname(String surname) {
this.surname = surname;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
}
Result:
In a JavaFX TreeView I'm using 'custom' classes which extend TreeItem. This makes me able to edit the items in the TreeView (I can double click them and edit the contents when running the application) but I can't seem to be able to set the .setOnEditCommit() method properly. I was hoping it'd work similar as the function in a tableview but I didn't have any luck yet.
This is my code in my controller in which I try to set the setOnEditCommit() method. In my TreeView called 'trvDivisies' I display football team divisions / competitions and one level lower I display all the teams that are in a certain division.
private void setUpTreeView() {
trvDivisies.setEditable(true);
trvDivisies.setShowRoot(false);
TreeItem<String> root = new TreeItem<>();
for (Divisie d : divisies) {
TreeItem<String> divisieTreeItem = d;
divisieTreeItem.valueProperty().set(d.getNaam());
for (VoetbalTeam vt : d.getVoetbalTeams()) {
TreeItem<String> voetbalTeamTreeItem = vt;
voetbalTeamTreeItem.valueProperty().setValue(vt.getTeamNaam());
divisieTreeItem.getChildren().add(voetbalTeamTreeItem);
}
root.getChildren().add(divisieTreeItem);
}
trvDivisies.setRoot(root);
trvDivisies.getSelectionModel().selectedItemProperty().addListener(new ChangeListener() {
#Override
public void changed(ObservableValue observable, Object oldValue, Object newValue) {
System.out.println(newValue);
}
});
trvDivisies.setCellFactory(TextFieldTreeCell.forTreeView());
// I get an error at the following line when compiling
trvDivisies.setOnEditCommit((TreeView.EditEvent p) -> {
TreeItem<String> selectedItem = p.getTreeItem();
if (selectedItem instanceof Divisie) {
updateDivisie((Divisie)selectedItem);
} else if (selectedItem instanceof VoetbalTeam) {
updateTeam((VoetbalTeam)selectedItem);
}
});
}
This is what my 'custom' classes look like.
public class Divisie extends TreeItem<String> {
private static int idCount = 0;
private int id;
private String naam;
private List<VoetbalTeam> voetbalTeams;
public int getId() {
return id;
}
public String getNaam() {
return naam;
}
public List<VoetbalTeam> getVoetbalTeams() {
return voetbalTeams;
}
public Divisie(int id, String naam) {
super(naam);
this.id = id;
this.naam = naam;
}
public Divisie(String naam) {
this.id = ++idCount;
this.naam = naam;
}
public void addTeam(VoetbalTeam toBeAdded) {
if (voetbalTeams == null) {
voetbalTeams = new LinkedList<>();
}
voetbalTeams.add(toBeAdded);
}
#Override
public String toString() {
return this.naam;
}
}
Second 'lower level' class
public class VoetbalTeam extends TreeItem<String> {
private static int idCount = 0;
private int id;
private String teamNaam;
private List<Speler> spelers;
public int getId() {
return id;
}
public String getTeamNaam() {
return teamNaam;
}
public List<Speler> getSpelers() {
return this.spelers;
}
public VoetbalTeam(int id, String teamNaam) {
super(teamNaam);
this.id = id;
this.teamNaam = teamNaam;
}
public VoetbalTeam(String teamNaam) {
super(teamNaam);
this.id = ++idCount;
this.teamNaam = teamNaam;
}
public void addSpeler(Speler nieuweSpeler) {
if (spelers == null) {
spelers = new LinkedList<>();
}
this.spelers.add(nieuweSpeler);
}
#Override
public String toString() {
return this.teamNaam;
}
}
When trying to run the application WITH the .setOnEditCommit() method I get an error saying:
Error:(97, 37) java: incompatible types: incompatible parameter types in lambda expression
I was hoping you guys can tell me what I need to change my TreeView.EditEvent lambda to or help me find an easier solution.
For a TreeView<T>, the signature of setOnEditCommit is
void setOnEditCommit(EventHandler<TreeView.EditEvent<T>> value)
Since you have (apparently) a TreeView<String>, you need
trvDivisies.setOnEditCommit((TreeView.EditEvent<String> p) -> {
// ...
});
Or, of course, you can just let the compiler do the work for you:
trvDivisies.setOnEditCommit(p -> {
// ...
});
There is a very similar question to this already, but mine's a bit different. I am using properties and on observable list to change it, it won't update.
Original question is here.
So when I am transferring rows between tables, like this:
The first row would appear, but when adding more than one would cause the ones after the first row to not update, like this:
They only reappear when I move around the columns though.
//Loot identification
TableColumn lootIdentCol = new TableColumn<>("Identification");
TableColumn<ItemDef, Integer> lootIDCol = new TableColumn<>("ID");
lootIDCol.setCellValueFactory(
new PropertyValueFactory<ItemDef, Integer>("id"));
TableColumn<ItemDef, String> lootNameCol = new TableColumn<>("Name");
lootNameCol.setCellValueFactory(
new PropertyValueFactory<ItemDef, String>("name"));
lootIdentCol.getColumns().addAll(lootNameCol, lootIDCol);
//Loot price
TableColumn<ItemDef, Integer> lootPriceCol = new TableColumn<>("Price");
lootPriceCol.setCellValueFactory(
new PropertyValueFactory<ItemDef, Integer>("price"));
//To loot items table
toLootItemsTableView.getColumns().addAll(lootIdentCol, lootPriceCol);
grid.add(toLootItemsTableView, 0, 1);
//Lootable items table
lootableItemsTableView.getColumns().addAll(lootIdentCol, lootPriceCol);
grid.add(lootableItemsTableView, 2, 1);
toLootItemsTableView.setColumnResizePolicy(TableView.CONSTRAINED_RESIZE_POLICY);
lootableItemsTableView.setColumnResizePolicy(TableView.CONSTRAINED_RESIZE_POLICY);
lootableItemsTableView.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);
toLootItemsTableView.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);
lootableTableList.add(new ItemDef("Ab", 141, false, false));
lootableTableList.add(new ItemDef("Ac", 25, false, false));
lootableTableList.add(new ItemDef("AD", 262, false, false));
AddRemoveButtons<ItemDef> addRemoveLootButtons = new AddRemoveButtons<>(
lootableTableList, lootableItemsTableView.getSelectionModel(),
toLootTableList, toLootItemsTableView.getSelectionModel()
);
Code for AddRemoveButtons:
private final ObservableList<E> fromList;
private final ObservableList<E> toList;
public AddRemoveButtons(final ObservableList<E> fromList, final SelectionModel<E> from,
final ObservableList<E> toList, final SelectionModel<E> to) {
this.fromList = fromList;
this.toList = toList;
setAlignment(Pos.CENTER);
setPadding(new Insets(5, 5, 5, 5));
setSpacing(15);
ObservableList<Node> children = getChildren();
Button moveInto = new Button("Add");
moveInto.setOnMouseClicked(new EventHandler<MouseEvent>() {
#Override
public void handle(MouseEvent mouseEvent) {
if (from instanceof MultipleSelectionModel) {
MultipleSelectionModel<E> multipleFrom = (MultipleSelectionModel<E>) from;
ObservableList<Integer> selectedIndices = multipleFrom.getSelectedIndices();
for (int i : selectedIndices)
transfer(i, true);
} else
transfer(from.getSelectedIndex(), true);
}
});
Button delete = new Button("Del");
delete.setOnMouseClicked(new EventHandler<MouseEvent>() {
#Override
public void handle(MouseEvent mouseEvent) {
if (to instanceof MultipleSelectionModel) {
MultipleSelectionModel<E> multipleFrom = (MultipleSelectionModel<E>) to;
ObservableList<Integer> selectedIndices = multipleFrom.getSelectedIndices();
for (int i : selectedIndices)
transfer(i, false);
} else
transfer(to.getSelectedIndex(), false);
}
});
children.addAll(moveInto, delete);
}
private void transfer(int index, boolean forward) {
if (forward)
toList.add(fromList.remove(index));
else
fromList.add(toList.remove(index));
}
ItemDef which implements Identifiable, Serializable, Comparable:
private final String name;
private final int id;
private final boolean members;
private final boolean stackable;
private int price;
public ItemDef(JSONObject jsonObject) {
this(
(String) jsonObject.get("name"),
Integer.parseInt((String) jsonObject.get("id")),
Boolean.parseBoolean((String) jsonObject.get("members")),
Boolean.parseBoolean((String) jsonObject.get("stackable"))
);
}
public ItemDef(String name, int id, boolean members, boolean stackable) {
this.name = name;
this.id = id;
this.members = members;
this.stackable = stackable;
price = -1;
}
public String getName() {
return name;
}
#Override
public int getId() {
return id;
}
public boolean isMembers() {
return members;
}
public boolean isStackable() {
return stackable;
}
public int getPrice() {
return price != -1 ? price : updatePrice();
}
//Other methods not relevant
Figured out why it kept doing that.
You just can't have the same TableColumn being referenced on multiple tables.
You should not share columns in multiple tables if you want data to update in multiple tables share the data set between them not the columns.
How do I use the JdbcTemplate.query()/queryForList() to run a query using namedParameter and store the result set into a List of 'User's?
User Class:
public class User {
String name = null;
String id = null;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getId() {
return name;
}
public void setId(String id) {
this.id = id;
}
}
Query:
SELECT name, id FROM USERS where email=:email
I'm looking for something like:
ArrayList<User> userList = jdbcTemplate.query(sql_query,
...some_mapper..., etc);
Seems like the answer to the question is not available at one place, on the Internet. Here's what I found out:
For adding the resultset into a List<>, we can use the NamedParameterJdbcTemplate.query() function:
NamedParameterJdbcTemplate jdbcTemplate;
ArrayList<User> usersSearchResult = (ArrayList<User>) jdbcTemplate.query(
USER_LIST_TP_query,
namedParameters,
new RowMapperResultSetExtractor<User>(new UserRowMapper(), 20));
We also have to define a custom RowMapperResultSetExtractor so that JDBC can understand how to convert each row in the result set to the type User.
private class UserRowMapper implements RowMapper<User> {
public User mapRow(ResultSet rs, int rowNum) throws SQLException {
User user = new User();
user.setId(rs.getString("ID"));
user.setName(rs.getString("NAME"));
return user;
}
}