zivce

// two-level functions; wrapper of the recursive one
private void Horners(double[] coeff, double x, int n) {
 this.x = x;
 this.coeff = coeff; 
 H(n);
}
private double H(int k)
{
 if (k == 0) {
   return coeff[0];

zivce

INSERT_UPDATE MinConstraint;id[unique=true];severity(code,itemtype(code));active;annotation;descriptor(enclosingType(code),qualifier);message[lang=de];message[lang=en];value
                           ;AlbumSalesMustNotBeNegative;ERROR:Severity;true;javax.validation.constraints.Min;Band:albumSales;Albumverkäufe dürfen nicht negativ sein;Album sales must not be negative;1

INSERT_UPDATE NotLoremIpsumConstraint;id[unique=true];severity(code,itemtype(code));active;annotation;descriptor(enclosingType(code),qualifier);message[lang=de];message[lang=en]
                                     ;BandHistoryNotIpsum;ERROR:Severity;true;concerttours.constraints.NotLoremIpsum;Band:history;Band Geschichte sollte nicht Lorem ipsum Platzhalter Text.;Band history should not be Lorem ipsum placeholder text.;

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Optional.of(opt).map(value -> { System.out.println(value);
                                return value; })
              .orElseGet(() -> { System.out.println("not present");
                                return -1;});

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Optionals.ifPresentOrElse(opt, System.out::println,
      () -> System.out.println("not present"));

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opt.ifPresentOrElse(System.out::println,
      () -> System.out.println("not present"));

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opt.<Runnable>map(value -> () -> System.out.println("Found " + value))
   .orElse(() -> System.out.println("Not present!"))
   .run();

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public Optional<StoreConfiguration> update(Store store, String value) {
    return store.getConfigurationId() // Optional<UUID>
        .flatMap(storeConfigurationRepository::findById) // Optional<StoreConfiguration>
        .map(config -> this.updateStoreConfiguration(store,value)) // Optional<StoreConfiguration>
}

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public StoreConfiguration updateConfig(Store store, String value) {
    return store.getConfigurationId().map(configurationId ->{
        return storeConfigurationRepository.findById(configurationId).map(storeConfiguration -> {
            return updateStoreConfiguration(storeConfiguration, value); 
        }).orElseThrow();
    }).orElseThrow();
}

zivce

getValue(x).orElse(getValue(y)
                  .orElseThrow(() -> new NotFoundException("value not present")));

public Optional<Value> getValue(Source s)
{
  System.out.println("Source: " + s.getName());
  
  // returns value from s source
}

zivce

getValue(x).orElseGet(() -> getValue(y)
                  .orElseThrow(() -> new NotFoundException("value not present")));

public Optional<Value> getValue(Source s)
{
  System.out.println("Source: " + s.getName());
  
  // returns value from s source
}