info.unterrainer.commons.jreutils.Exceptions Maven / Gradle / Ivy
package info.unterrainer.commons.jreutils;
import java.util.function.Supplier;
import lombok.experimental.UtilityClass;
@UtilityClass
public class Exceptions {
/**
* Swallows any given Exception (checked or unchecked alike) silently that is
* thrown when running the given supplier.
*
* @param runnable the {@link Runnable} that could throw the exception to
* swallow
* @param exceptions a List of Exception-types
*/
@SafeVarargs
public static void swallow(final Runnable runnable, final Class... exceptions) {
Supplier supplier = () -> {
runnable.run();
return null;
};
swallowReturning(supplier, exceptions);
}
/**
* Swallows any given Exception (checked or unchecked alike) silently that is
* thrown when running the given supplier and returns the return-value
* otherwise.
*
* @param the return-value of the {@link Supplier}
* @param supplier the {@link Supplier} that could throw the exception to
* swallow
* @param exceptions a List of Exception-types
* @return the return-value of the {@link Supplier}
*/
@SafeVarargs
public static T swallowReturning(final Supplier supplier, final Class... exceptions) {
try {
return supplier.get();
} catch (Throwable e) {
if (!containsException(e, exceptions))
throw e;
return null;
}
}
/**
* If one of the specified exceptions occur while running the given supplier, it
* retries running the supplier [times] times with [backOffInMillis]ms in
* between tries.
*
* If the number of retries are used up and the supplier still throws an
* exception, that exception is re-thrown.
*
* @param runnable the {@link Runnable} that could throw the exception to
* swallow
* @param times the number of times to retry before throwing the
* exception for real
* @param backOffInMillis the time to wait in between retries
* @param exceptions a List of Exception-types to retry upon
*/
@SafeVarargs
public static void retry(final int times, final long backOffInMillis, final Runnable runnable,
final Class... exceptions) {
Supplier supplier = () -> {
runnable.run();
return null;
};
retryReturning(times, backOffInMillis, supplier, exceptions);
}
/**
* If one of the specified exceptions occur while running the given supplier, it
* retries running the supplier [times] times with [backOffInMillis]ms in
* between tries. It returns the return-value of the given supplier.
*
* If the number of retries are used up and the supplier still throws an
* exception, that exception is re-thrown.
*
* @param the return-value of the {@link Supplier}
* @param supplier the {@link Supplier} that could throw the exception to
* retry upon
* @param times the number of times to retry before throwing the
* exception for real
* @param backOffInMillis the time to wait in between retries
* @param exceptions a List of Exception-types to retry upon
* @return the return-value of the {@link Supplier}
*/
@SafeVarargs
public static T retryReturning(final int times, final long backOffInMillis, final Supplier supplier,
final Class... exceptions) {
for (int i = 0; i < times; i++)
try {
return supplier.get();
} catch (Throwable e) {
if (!containsException(e, exceptions) || i == times - 1)
throw e;
try {
Thread.sleep(backOffInMillis);
} catch (InterruptedException e1) {
Thread.currentThread().interrupt();
}
}
return null;
}
public static boolean containsException(final Throwable e, final Class... exceptions) {
for (Class omit : exceptions)
if (equalsOrCauseEquals(e, omit))
return true;
return false;
}
private static boolean equalsOrCauseEquals(final Throwable e, final Class omit) {
if (omit.isAssignableFrom(e.getClass()))
return true;
Throwable cause = e.getCause();
if (cause != null && equalsOrCauseEquals(cause, omit))
return true;
return false;
}
}