Throwables class provides utility methods related to Throwable interface.
Class Declaration
Following is the declaration for com.google.common.base.Throwables class −
public final class Throwables extends Object
Class Methods
| Sr.No | Method & Description |
|---|---|
| 1 | static List<Throwable> getCausalChain(Throwable throwable)Gets a Throwable cause chain as a list. |
| 2 | static Throwable getRootCause(Throwable throwable)Returns the innermost cause of throwable. |
| 3 | static String getStackTraceAsString(Throwable throwable)Returns a string containing the result of toString(), followed by the full, recursive stack trace of throwable. |
| 4 | static RuntimeException propagate(Throwable throwable)Propagates throwable as-is if it is an instance of RuntimeException or Error, or else as a last resort, wraps it in a RuntimeException then propagates. |
| 5 | static <X extends Throwable> void propagateIfInstanceOf(Throwable throwable, Class<X> declaredType)Propagates throwable exactly as-is, if and only if it is an instance of declaredType. |
| 6 | static void propagateIfPossible(Throwable throwable)Propagates throwable exactly as-is, if and only if it is an instance of RuntimeException or Error. |
| 7 | static <X extends Throwable> void propagateIfPossible(Throwable throwable, Class<X> declaredType)Propagates throwable exactly as-is, if and only if it is an instance of RuntimeException, Error, or declaredType. |
| 8 | static <X1 extends Throwable,X2 extends Throwable>void propagateIfPossible(Throwable throwable, Class<X1> declaredType1, Class<X2> declaredType2)Propagates throwable exactly as-is, if and only if it is an instance of RuntimeException, Error, declaredType1, or declaredType2. |
Methods Inherited
This class inherits methods from the following class −
- java.lang.Object
Example of Throwables Class
Create the following java program using any editor of your choice in say C:/> Guava.
GuavaTester.java
import java.io.IOException;
import com.google.common.base.Objects;
import com.google.common.base.Throwables;
public class GuavaTester {
public static void main(String args[]) {
GuavaTester tester = new GuavaTester();
try {
tester.showcaseThrowables();
} catch (InvalidInputException e) {
//get the root cause
System.out.println(Throwables.getRootCause(e));
} catch (Exception e) {
//get the stack trace in string format
System.out.println(Throwables.getStackTraceAsString(e));
}
try {
tester.showcaseThrowables1();
} catch (Exception e) {
System.out.println(Throwables.getStackTraceAsString(e));
}
}
public void showcaseThrowables() throws InvalidInputException {
try {
sqrt(-3.0);
} catch (Throwable e) {
//check the type of exception and throw it
Throwables.propagateIfInstanceOf(e, InvalidInputException.class);
Throwables.propagate(e);
}
}
public void showcaseThrowables1() {
try {
int[] data = {1,2,3};
getValue(data, 4);
} catch (Throwable e) {
Throwables.propagateIfInstanceOf(e, IndexOutOfBoundsException.class);
Throwables.propagate(e);
}
}
public double sqrt(double input) throws InvalidInputException {
if(input < 0) throw new InvalidInputException();
return Math.sqrt(input);
}
public double getValue(int[] list, int index) throws IndexOutOfBoundsException {
return list[index];
}
public void dummyIO() throws IOException {
throw new IOException();
}
}
class InvalidInputException extends Exception {
}
Verify the Result
Compile the class using javac compiler as follows −
C:\Guava>javac GuavaTester.java
Now run the GuavaTester to see the result.
C:\Guava>java GuavaTester
See the result.
InvalidInputException java.lang.ArrayIndexOutOfBoundsException: 4 at GuavaTester.getValue(GuavaTester.java:52) at GuavaTester.showcaseThrowables1(GuavaTester.java:38) at GuavaTester.main(GuavaTester.java:19)
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