I am currently new to interfaces and I encountered this problem regarding my getArea(), I would love if you guys can point out the error on my code
while this is my Triangle abstract class, I am not sure whether I putted the Semi-perimeter(sp) right or not:
private int sideA;
private int sideB;
private int sideC;
int sp = (sideA+sideB+sideC)/2;
double area = Math.sqrt(sp*(sp-sideA)*(sp-sideB)*(sp-sideC));
public Triangle() {
}
public Triangle(int sideA, int sideB, int sideC, int sp, double area) {
this.sideA=sideA;
this.sideB=sideB;
this.sideC=sideC;
}
public int getSideA() {
return sideA;
}
public void setSideA(int sideA) {
this.sideA = sideA;
}
public int getSideB() {
return sideB;
}
public void setSideB(int sideB) {
this.sideB = sideB;
}
public int getSideC() {
return sideC;
}
public void setSideC(int sideC) {
this.sideC = sideC;
}
public double getPerimeter() {
return sideA+sideB+sideC;
}
public double getArea() {
return getArea();
}
public void getDetails() {
System.out.println("\nType: Triangle" + "\nSides: " +this.sideA +", " +this.sideB+", "+this.sideC + "\nPerimeter: "
+ getPerimeter() + "\nArea: " + getArea() + "\ns: "+sp);
}
}```
Related
I had implement a interceptor of myabtis. but we found a problem, execute interceptor lead to throw so many IllegalAccessException, it affects cpu performence
Shown below is where the problem is, why did not check access permision of feild befor executed code "field.get(target)".
public class GetFieldInvoker implements Invoker {
private final Field field;
public GetFieldInvoker(Field field) {
this.field = field;
}
#Override
public Object invoke(Object target, Object[] args) throws IllegalAccessException {
try {
return field.get(target);
} catch (IllegalAccessException e) {
if (Reflector.canControlMemberAccessible()) {
field.setAccessible(true);
return field.get(target);
} else {
throw e;
}
}
}
#Override
public Class<?> getType() {
return field.getType();
}
}
the intercepor of mine:
#Intercepts({
#Signature(
type = StatementHandler.class,
method = "prepare",
args = {Connection.class, Integer.class})
})
public class SqlIdInterceptor implements Interceptor {
private static final int MAX_LEN = 256;
private final RoomboxLogger logger = RoomboxLogManager.getLogger();
#Override
public Object intercept(Invocation invocation) throws Throwable {
StatementHandler statementHandler = realTarget(invocation.getTarget());
MetaObject metaObject = SystemMetaObject.forObject(statementHandler);
BoundSql boundSql = (BoundSql) metaObject.getValue("delegate.boundSql");
String originalSql = boundSql.getSql();
MappedStatement mappedStatement =
(MappedStatement) metaObject.getValue("delegate.mappedStatement");
String id = mappedStatement.getId();
if (id != null) {
int len = id.length();
if (len > MAX_LEN) {
logger.warn("too long id", "id", id, "len", len);
}
}
String newSQL = "# " + id + "\n" + originalSql;
metaObject.setValue("delegate.boundSql.sql", newSQL);
return invocation.proceed();
}
#SuppressWarnings("unchecked")
public static <T> T realTarget(Object target) {
if (Proxy.isProxyClass(target.getClass())) {
MetaObject metaObject = SystemMetaObject.forObject(target);
return realTarget(metaObject.getValue("h.target"));
}
return (T) target;
}
}
Flame Graph
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I need help, how to avoid throw exceptions, is any other way to reslove this problem?
thanks.
I have a simple java type
public class Type1_ {
private int number1;
private int number2;
public Type1_(int number1, int number2) {
this.number1 = number1;
this.number2 = number2;
}
public int getNumber1() {
return number1;
}
public int getNumber2() {
return number2;
}
#Override
public String toString() {
return "Type1_{number1=" + number1 + ", number2=" + number2 + '}';
}
public static Type1_ random() {
return new Type1_(new SecureRandom().nextInt(), new SecureRandom().nextInt());
}
}
Created a simple Codec<Type1_> for this type (with loggers to know when or if they are being used)
public class Type1_Codec implements Codec<Type1_> {
#Override
public Type1_ decode(BsonReader reader, DecoderContext decoderContext) {
reader.readStartDocument();
final int number1 = reader.readInt32("number1");
final int number2 = reader.readInt32("number2");
reader.readEndDocument();
final Type1_ type1_ = new Type1_(number1, number2);
APP_LOGGER.debug(type1_);
return type1_;
}
#Override
public void encode(BsonWriter writer, Type1_ value, EncoderContext encoderContext) {
writer.writeStartDocument();
writer.writeInt32("number1", value.getNumber1());
writer.writeInt32("number2", value.getNumber2());
writer.writeEndDocument();
APP_LOGGER.debug(value);
}
#Override
public Class<Type1_> getEncoderClass() {
return Type1_.class;
}
}
Added the codec to a registry to be used in MongoClient
public class CustomCodecRegistriesFactory {
public static CodecRegistry getDefault() {
return MongoClientSettings.getDefaultCodecRegistry();
}
public static CodecRegistry getDefaultWithType1_() {
return CodecRegistries.fromRegistries(CodecRegistries.fromCodecs(new Type1_Codec()), getDefault());
}
}
public class MongoDBClientConfig {
public static MongoClient buildMongoClientWithCustomCodec(final CodecRegistry codecRegistry) {
return MongoClients.create(MongoClientSettings.builder()
.applyToClusterSettings(builder -> {
builder.hosts(Arrays.asList(new ServerAddress(url(), port())));
})
.codecRegistry(codecRegistry)
.build());
}
}
Created a test that uses a codec registry where the Type1_Codec is included and attempt to insert (encode) and read (decode) Type1_
#TestInstance(TestInstance.Lifecycle.PER_CLASS)
public class Codecs {
#Test
public void demonstrate_simpleCustomCodec() {
final MongoClient mongoClient = buildMongoClientWithCustomCodec(CustomCodecRegistriesFactory.getDefaultWithType1_());
final MongoDatabase db = mongoClient.getDatabase("db_" + new SecureRandom().nextInt(Integer.MAX_VALUE));
final String collectionName = "col1";
db.createCollection(collectionName);
final MongoCollection<Document> col1 = db.getCollection(collectionName);
int idCounter = 0;
final String type1_field = "type1_";
printTitle("Inserting Documents");
for (int i = 0; i < 10; i++) {
/*Encoding is done at insertion*/
col1.insertOne(new Document(ID, idCounter++).append(type1_field, Type1_.random()));
}
printDocumentMongoCollection(col1);
printMongoCollectionJackson(col1);
printTitle("Attempting Decoding");
/*attempt decoding*/
// final Type1_ type1_value = col1.find().first().get(type1_field, Type1_.class);
// System.out.println(type1_value);
}
}
The problem is in the decoding part.
How do i specify for MongoClient that i want a specific document to be decoded into Type1_ type?
The commented out code will attempt to cast a Document to Type1_ and will fail.
use db.getCollection(collectionName, Type1_.class) to "type" your collection. That should pull your codec in to play automatically for you.
Well, I'd like to provide QuickSearch result inside application, and, of course, through the lookup.
Searching works well, but found result is not visible through global lookup.
Can someone help to overcome this issue ?
Here is th code for a quicksearch :
public class QSERSCompany implements SearchProvider {
#Override
public void evaluate(SearchRequest request, SearchResponse response) {
try {
for (Company k : queries.ERSQuery.allCompanies()) {
if (k.getCompanyName().toLowerCase().contains(request.getText().toLowerCase())) {
if (!response.addResult(new SearchResult(k), k.getCompanyName())) {
return;
}
}
}
} catch (NullPointerException npe) {
}
}
private static class SearchResult implements Runnable, Lookup.Provider {
private final Company company;
private final InstanceContent ic = new InstanceContent();
private final Lookup lookup = new AbstractLookup(ic);
public SearchResult(Company c) {
this.company= c;
}
#Override
public void run() {
ic.add(company);
try {
StatusDisplayer.getDefault().setStatusText(
company.getCompanyName()
+ ", " + company.getAddress()
+ ", " + company.getCity());
} catch (NullPointerException npe) {
}
}
#Override
public Lookup getLookup() {
return lookup;
}
}
}
And this is partof the code which listens for a Company object :
public final class ManagementPodatakaTopComponent extends TopComponent {
private Lookup.Result<Company> companyLookup = null;
...
private Company selectedCompany;
...
#Override
public void componentOpened() {
companyLookup = Utilities.actionsGlobalContext().lookupResult(Company.class);
companyLookup .addLookupListener(new LookupListener() {
#Override
public void resultChanged(LookupEvent le) {
Lookup.Result k = (Lookup.Result) le.getSource();
Collection<Company> cs = k.allInstances();
for (Company k1 : cs) {
selectedCompany = k1;
}
setCompanyTextFields(selectedCompany);
jTP_DataManagement.setVisible(true);
jPanel_Entiteti.setVisible(true);
}
});
}
A SearchResult which provides a lookup? Never seen this in the wild.
Please ask at nbdev#netbeans.org to get better feedback (probably from one of the NB devs)
I finally managed somehow to get what I want :
First off, define interface:
public interface ICodes {
public Code getCode();
}
Then, we implement quick search :
#ServiceProvider(service = ICodes.class)
public class ClientServicesQS implements SearchProvider, ICodes {
private static Code code = null;
#Override
public void evaluate(SearchRequest request, SearchResponse response) {
try {
for (Code c : INFSYS.queries.INFSistemQuery.ByersByName(request.getText())) {
if (!response.addResult(new SearchResult(c),
c.getName() + " ,Code: " + c.getByerCode()
+ (c.getAddress() != null ? ", " + c.getAddress() : ""))) {
return;
}
}
} catch (NullPointerException npe) {
StatusDisplayer.getDefault().setStatusText("Error." + npe.getMessage());
}
}
#Override
public Code getCode() {
return ClientServicesQS.sifra;
}
private static class SearchResult implements Runnable {
private final Code code;
public SearchResult(Code code) {
this.code= code;
}
#Override
public void run() {
try {
ClientServicesQS.code= this.code;
OpenTopComponent("ClientServicesTopComponent");
} catch (NullPointerException e) {
Display.messageBaloon("Error.", e.toString() + ", " + e.getMessage(), Display.TYPE_MESSAGE.ERROR);
}
}
}
}
Finally, we implement lookup in other module through platform.
Because I want to call lookup whenever componentOpen, oe componentActivated is invoked, it is usefull first to define :
private void QSCodeSearch() {
try {
ICode ic= Lookup.getDefault().lookup(ICode.class);
if ((code = ic.getCode()) != null) {
.
.
.
// setup UI components with data from lookup
.
.
.
}
} catch (Exception e) {
}
}
And when topcomponent is activated, we call QSCodeSearch() in :
#Override
public void componentOpened() {
...
QSCodeSearch()
...
}
...
#Override
public void requestActive() {
...
QSCodeSearch()
...
}
I have one [JavaFX] ComboBox that is populated with countries.
My object:
public static class CountryObj {
private String TCountryDescr;
private String TCountryCode;
private CountryObj(String CountryDescr,String CountryCode) {
this.TCountryDescr = CountryDescr;
this.TCountryCode = CountryCode;
}
public String getTCountryCode() {
return TCountryCode;
}
public void setTCountryCode(String fComp) {
TCountryCode= fComp;
}
public String getTCountryDescr() {
return TCountryDescr;
}
public void setCountryDescr(String fdescr) {
TCountryDescr = fdescr;
}
#Override
public String toString() {
return TCountryDescr;
}
}
Then I have my ObservableList:
private final ObservableList<CountryObj> CountrycomboList =
FXCollections.observableArrayList(
new CountryObj("United States", "US"),
new CountryObj("United Kingdom", "UK"),
new CountryObj("France", "FR"),
new CountryObj("Germany", "DE"));
Then my ComboBox which displays the name of the country and the code of the country is for my own use:
private ComboBox<CountryObj> cCountry1 = new ComboBox<>();
cbCountry1.setItems(CountrycomboList);
cbCountry1.getSelectionModel().selectedItemProperty().addListener(new ChangeListener<CountryObj>() {
#Override
public void changed(ObservableValue<? extends CountryObj> arg0, CountryObj arg1, CountryObj arg2) {
if (arg2 != null) {
System.out.println("Selected Country: " + arg2.getTCountryCode());
}
}
});
How can I auto-select a country, for example Germany, if I only have the code of the country, which is "DE"?
comboBox.getSelectionModel().select(indexOfItem);
or
comboBox.setValue("item1");
Couple of months old question but here is more elegant solution for such type of problems.
Modify the CountryObj class and override the hashCode and equals functions as below:
public class CountryObj {
private String TCountryDescr;
private String TCountryCode;
public CountryObj(String CountryDescr,String CountryCode) {
this.TCountryDescr = CountryDescr;
this.TCountryCode = CountryCode;
}
public String getTCountryCode() {
return TCountryCode;
}
public void setTCountryCode(String fComp) {
TCountryCode= fComp;
}
public String getTCountryDescr() {
return TCountryDescr;
}
public void setCountryDescr(String fdescr) {
TCountryDescr = fdescr;
}
#Override
public String toString() {
return TCountryDescr;
}
#Override
public int hashCode() {
int hash = 0;
hash += (TCountryCode != null ? TCountryCode.hashCode() : 0);
return hash;
}
#Override
public boolean equals(Object object) {
String otherTCountryCode = "";
if (object instanceof Country) {
otherTCountryCode = ((Country)object).TCountryCode;
} else if(object instanceof String){
otherTCountryCode = (String)object;
} else {
return false;
}
if ((this.TCountryCode == null && otherTCountryCode != null) || (this.TCountryCode != null && !this.TCountryCode.equals(otherTCountryCode))) {
return false;
}
return true;
}
}
Now in you code if you will execute the following statement, it will automatically select "Germany" for you.
cmbCountry.getSelectionModel().select("DE")
You can also pass an object of CountryObj to select method above.
I think the simplest solution is to write an autoSelect function that finds the matching CountryObj in your ObservableList. Once you find the correct CountryObj, tell the combobox to set that as its value. It should looks something like this...
private void autoSelectCountry(String countryCode)
{
for (CountryObj countryObj : countryComboList)
{
if (countryObj.getTCountryCode().equals(countryCode))
{
cbCountry1.setValue(countryObj);
}
}
}
EDIT:
This can be further refactored to reusable method for all ComboBox'es that take different type parameter:
public static <T> void autoSelectComboBoxValue(ComboBox<T> comboBox, String value, Func<T, String> f) {
for (T t : comboBox.getItems()) {
if (f.compare(t, value)) {
comboBox.setValue(t);
}
}
}
where Func is an interface:
public interface Func<T, V> {
boolean compare(T t, V v);
}
How to apply this method:
autoSelectComboBoxValue(comboBox, "Germany", (cmbProp, val) -> cmbProp.getNameOfCountry().equals(val));
If both comboBox are from the same Array, assembly column one and two, then they have the same sequence. Then you can use the index.
a = comboBox1.getSelectionModel().getSelectedIndex();
comboBox2.getSelectionModel().select(a);
"United States" is on index position 1 "US" also on index position 1 then:
comboBox2.getSelectionModel().select(1); // is "US"
The solution of Brendan and Branislav Lazic is perfect, but we still can improve the call to the autoSelectComboBoxValue method :
public static <T, V> void autoSelectComboBoxValue(ComboBox<T> comboBox, V value, Func<T, V> f) {...}
:)
I am trying to understand this example from a MSDN article, to my understanding with the IEnumberable interface, we will be able to use Foreach to loop through the class collection, I am confused at the Main method, why don't we just use:
foreach (Person p in peopleArray)
Console.WriteLine(p.firstName + " " + p.lastName);
instead of
People peopleList = new People(peopleArray);
foreach (Person p in peopleList)
Console.WriteLine(p.firstName + " " + p.lastName);
Example:
using System;
using System.Collections;
public class Person
{
public Person(string fName, string lName)
{
this.firstName = fName;
this.lastName = lName;
}
public string firstName;
public string lastName;
}
public class People : IEnumerable
{
private Person[] _people;
public People(Person[] pArray)
{
_people = new Person[pArray.Length];
for (int i = 0; i < pArray.Length; i++)
{
_people[i] = pArray[i];
}
}
IEnumerator IEnumerable.GetEnumerator()
{
return (IEnumerator) GetEnumerator();
}
public PeopleEnum GetEnumerator()
{
return new PeopleEnum(_people);
}
}
public class PeopleEnum : IEnumerator
{
public Person[] _people;
// Enumerators are positioned before the first element
// until the first MoveNext() call.
int position = -1;
public PeopleEnum(Person[] list)
{
_people = list;
}
public bool MoveNext()
{
position++;
return (position < _people.Length);
}
public void Reset()
{
position = -1;
}
object IEnumerator.Current
{
get
{
return Current;
}
}
public Person Current
{
get
{
try
{
return _people[position];
}
catch (IndexOutOfRangeException)
{
throw new InvalidOperationException();
}
}
}
}
class App
{
static void Main()
{
Person[] peopleArray = new Person[3]
{
new Person("John", "Smith"),
new Person("Jim", "Johnson"),
new Person("Sue", "Rabon"),
};
People peopleList = new People(peopleArray);
foreach (Person p in peopleList)
Console.WriteLine(p.firstName + " " + p.lastName);
}
}
You're right, you could simply use the first version because arrays implement IEnumerable.
The reason they chose to iterate over People is simply for academic purposes; to demonstrate how iterators work (and how to implement IEnumerable). If they simply iterated over peoplearray, they wouldn't be using the People class, which is the main focus of that example.