com.yahoo.yolean.Exceptions Maven / Gradle / Ivy
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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.yolean;
import java.io.IOException;
import java.io.UncheckedIOException;
import java.util.Optional;
import java.util.function.Function;
/**
* Helper methods for handling exceptions
*
* @author bratseth
*/
public class Exceptions {
/**
* Returns a user friendly error message string which includes information from all nested exceptions.
*
* The form of this string is
* e.getMessage(): e.getCause().getMessage(): e.getCause().getCause().getMessage()...
* In addition, some heuristics are used to clean up common cases where exception nesting causes bad messages.
*/
public static String toMessageString(Throwable t) {
StringBuilder b = new StringBuilder();
String lastMessage = null;
String message;
for (; t != null; t = t.getCause()) {
message = getMessage(t);
if (message == null) continue;
if (message.isEmpty()) continue;
if (message.equals(lastMessage)) continue;
if (b.length() > 0) {
b.append(": ");
}
b.append(message);
lastMessage = message;
}
return b.toString();
}
/** Returns a useful message from *this* exception, or null if there is nothing useful to return */
private static String getMessage(Throwable t) {
String message = t.getMessage();
if (t.getCause() == null) {
if (message == null) return t.getClass().getSimpleName();
} else {
if (message == null) return null;
if (message.equals(t.getCause().getClass().getName() + ": " + t.getCause().getMessage())) return null;
}
return message;
}
/**
* Returns the first cause or the given throwable that is an instance of {@code clazz}
*/
public static Optional findCause(Throwable t, Class clazz) {
for (; t != null; t = t.getCause()) {
if (clazz.isInstance(t))
return Optional.of(clazz.cast(t));
}
return Optional.empty();
}
/**
* Wraps any IOException thrown from a runnable in an UncheckedIOException.
*/
public static void uncheck(RunnableThrowingIOException runnable) {
try {
runnable.run();
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
public static void uncheckInterrupted(RunnableThrowingInterruptedException runnable) {
try {
runnable.run();
} catch (InterruptedException e) {
throw new UncheckedInterruptedException(e, false);
}
}
public static void uncheckInterruptedAndRestoreFlag(RunnableThrowingInterruptedException runnable) {
try {
runnable.run();
} catch (InterruptedException e) {
throw new UncheckedInterruptedException(e, true);
}
}
/**
* Wraps any IOException thrown from a runnable in an UncheckedIOException w/message.
*/
public static void uncheck(RunnableThrowingIOException runnable, String format, String... args) {
try {
runnable.run();
} catch (IOException e) {
String message = String.format(format, (Object[]) args);
throw new UncheckedIOException(message, e);
}
}
/** Similar to uncheck(), except an exceptionToIgnore exception is silently ignored. */
public static void uncheckAndIgnore(RunnableThrowingIOException runnable, Class exceptionToIgnore) {
try {
runnable.run();
} catch (UncheckedIOException e) {
IOException cause = e.getCause();
if (cause == null) throw e;
try {
cause.getClass().asSubclass(exceptionToIgnore);
} catch (ClassCastException f) {
throw e;
}
// Do nothing - OK
} catch (IOException e) {
try {
e.getClass().asSubclass(exceptionToIgnore);
} catch (ClassCastException f) {
throw new UncheckedIOException(e);
}
// Do nothing - OK
}
}
@FunctionalInterface
public interface RunnableThrowingIOException {
void run() throws IOException;
}
@FunctionalInterface public interface RunnableThrowingInterruptedException { void run() throws InterruptedException; }
/**
* Wraps any IOException thrown from a function in an UncheckedIOException.
*/
public static Function uncheck(FunctionThrowingIOException function) {
return t -> uncheck(() -> function.map(t));
}
@FunctionalInterface public interface FunctionThrowingIOException { R map(T t) throws IOException; }
/**
* Wraps any IOException thrown from a supplier in an UncheckedIOException.
*/
public static T uncheck(SupplierThrowingIOException supplier) {
try {
return supplier.get();
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
/**
* Wraps any IOException thrown from a supplier in an UncheckedIOException w/message.
*/
public static T uncheck(SupplierThrowingIOException supplier, String format, String... args) {
try {
return supplier.get();
} catch (IOException e) {
String message = String.format(format, (Object[]) args);
throw new UncheckedIOException(message, e);
}
}
/** Similar to uncheck(), except null is returned if exceptionToIgnore is thrown. */
public static R uncheckAndIgnore(SupplierThrowingIOException supplier, Class exceptionToIgnore) {
try {
return supplier.get();
} catch (UncheckedIOException e) {
IOException cause = e.getCause();
if (cause == null) throw e;
try {
cause.getClass().asSubclass(exceptionToIgnore);
} catch (ClassCastException f) {
throw e;
}
return null;
} catch (IOException e) {
try {
e.getClass().asSubclass(exceptionToIgnore);
} catch (ClassCastException f) {
throw new UncheckedIOException(e);
}
return null;
}
}
@FunctionalInterface
public interface SupplierThrowingIOException {
T get() throws IOException;
}
/**
* Allows treating checked exceptions as unchecked.
* Usage:
* throw throwUnchecked(e);
* The reason for the return type is to allow writing throw at the call site
* instead of just calling throwUnchecked. Just calling throwUnchecked
* means that the java compiler won't know that the statement will throw an exception,
* and will therefore complain on things such e.g. missing return value.
*/
public static RuntimeException throwUnchecked(Throwable e) {
throwUncheckedImpl(e);
return new RuntimeException(); // Non-null return value to stop tooling from complaining about potential NPE
}
@SuppressWarnings("unchecked")
private static void throwUncheckedImpl(Throwable t) throws T {
throw (T)t;
}
}