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package ch.epfl.xblast;
import ch.epfl.cs108.Sq;
import java.util.Collection;
import java.util.Objects;
/**
* ArgumentChecker.
*
* @author Pacien TRAN-GIRARD (261948)
* @author Timothée FLOURE (257420)
*/
public final class ArgumentChecker {
private ArgumentChecker() {
// Static class
}
/**
* Returns the given value if it is non-negative.
*
* @param v the tested value
* @return the given value if non-negative
* @throws IllegalArgumentException if the value is inferior to 0
*/
public static int requireNonNegative(int v) {
if (v < 0)
throw new IllegalArgumentException();
return v;
}
/**
* Requires the given Collection to be non-empty and returns it or throw an IllegalArgumentException otherwise.
*
* @param c the Collection to check
* @param <T> the Collection type
* @return the checked Collection
*/
public static <T extends Collection> T requireNonEmpty(T c) {
if (Objects.requireNonNull(c).isEmpty())
throw new IllegalArgumentException();
return c;
}
/**
* Requires the given Sequence to be non-empty and returns it or throw an IllegalArgumentException otherwise.
*
* @param s the sequence to check
* @param <T> the sequence type
* @return the checked sequence
*/
public static <T extends Sq> T requireNonEmpty(T s) {
if (Objects.requireNonNull(s).isEmpty())
throw new IllegalArgumentException();
return s;
}
/**
* Returns the element from the array at the requested index, or null if it cannot be retrieved.
*
* @param array the array
* @param index the index
* @param <T> the type of element
* @return the requested element, or null
*/
public static <T> T getOrNull(T[] array, int index) {
if (Objects.isNull(array) || index < 0 || index >= array.length)
return null;
else
return array[index];
}
/**
* Parses and returns an integer, or return null on error.
*
* @param str the integer to parse
* @return the parsed integer, or null
*/
public static Integer parseIntOrNull(String str) {
try {
return Integer.parseInt(str);
} catch (NumberFormatException | NullPointerException e) {
return null;
}
}
}
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