Is it possible to use Java annotations, to achieve a similar functionality as a preprocessor
Tag : java , By : Johannes
Date : March 29 2020, 07:55 AM
To fix the issue you can do Annotations are not meant as a tool to transform code; they just add metadata to code. You can't use annotations for conditional compilation, for example. As Sun's tutorial on annotations says:
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Why can't I Implement Streams functionality in my JAVA project?
Date : March 29 2020, 07:55 AM
may help you . Streams and lambda expressions are Java 8 functionality. Upgrade your compiler.
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if-elseif-else like functionality with Java 8 streams
Tag : java , By : Daljit Dhadwal
Date : March 29 2020, 07:55 AM
I hope this helps . I have a list of objects, lets say Shapes. I would like to process them using a stream and return another object - ShapeType - based on what is in the list. , You can use public ShapeType resolveShapeType(final List<Shape> shapes) {
int sides = shapes.stream()
.mapToInt(Shape::getSideCount)
.filter(count -> count==4 || count==6)
.max().orElse(0);
return sides==6? ShapeType.HEXA: sides==4? ShapeType.RECT: ShapeType.GENERIC;
}
public ShapeType resolveShapeType(final List<Shape> shapes) {
OptionalInt first = IntStream.range(0, shapes.size())
.filter(index -> {
int count = shapes.get(index).getSideCount();
return count == 6 || count == 4;
})
.findFirst();
if(!first.isPresent()) return ShapeType.GENERIC;
int ix = first.getAsInt(), count = shapes.get(ix).getSideCount();
return count==6? ShapeType.HEXA: shapes.subList(ix+1, shapes.size()).stream()
.anyMatch(shape -> shape.getSideCount()==6)? ShapeType.HEXA: ShapeType.RECT;
}
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achieve replaceAll functionality in java 1.2
Tag : java , By : user93312
Date : March 29 2020, 07:55 AM
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Using Java 8 Supplier in streams to achieve lazy evaluation
Tag : java , By : user181945
Date : March 29 2020, 07:55 AM
hope this fix your issue I don't think this is possible using only standard Java classes. But you could write your own lazy evaluator and use that, for example (untested): public class LazyValue<T> implements Supplier<T> {
private T value;
private final Supplier<T> initializer;
public LazyValue(Supplier<T> initializer) {
this.initializer = initializer;
}
public T get() {
if (value == null) {
value = initializer.get();
}
return value;
}
}
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