java.lang.Object
- org.djutils.exceptions.Try

```
public final class Try
extends Object
```
The Try class has a number of static methods that make it easy to try-catch an exception for any Throwable class, including the standard Java exceptions and exceptions from libraries that are used in the project. Instead of:
```
 FileInputStream fis;
 try
 {
     fis = new FileInputStream(fileString);
 }
 catch (FileNotFoundException exception)
 {
     throw new IllegalArgumentException("File " + fileString + " is not a valid file.", exception);
 }
 try
 {
     fis.close();
 }
 catch (IOException exception)
 {
     throw new RuntimeException("Could not close the file.", exception);
 }
 
```
we can write:
```
 FileInputStream fis = Try.assign(() -> new FileInputStream(fileString), IllegalArgumentException.class,
         "File %s is not a valid file.", fileString);
 Try.execute(() -> fis.close(), "Could not close the file.");
 
```
The exception message can be formatted with additional arguments, such that the overhead of building the exception message only occurs if the exception condition is met. For each method there is a version without Throwable class, in which case a RuntimeException will be thrown.

Try is not suitable for try-with-resource statements.

Try also has a few methods to aid JUNIT tests: testFail(...) and testNotFail(...).
Copyright (c) 2016-2021 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See for project information https://djutils.org. The DJUTILS project is distributed under a three-clause BSD-style license, which can be found at https://djutils.org/docs/license.html.
Author:

Alexander Verbraeck, Peter Knoppers, Wouter Schakel

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static interface`	`Try.Assignment<V>`	Functional interface for calls to Try.assign(...).
`static interface`	`Try.Execution`	Functional interface for calls to Try.execute(...).

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static <V,T extends Throwable> V`	`assign(Try.Assignment<V> assignment, Class<T> throwableClass, String message)`	Tries to return a value to assign.
`static <V,T extends Throwable> V`	`assign(Try.Assignment<V> assignment, Class<T> throwableClass, String message, Object arg)`	Tries to return a value to assign.
`static <V,T extends Throwable> V`	`assign(Try.Assignment<V> assignment, Class<T> throwableClass, String message, Object arg1, Object arg2)`	Tries to return a value to assign.
`static <V,T extends Throwable> V`	`assign(Try.Assignment<V> assignment, Class<T> throwableClass, String message, Object arg1, Object arg2, Object arg3)`	Tries to return a value to assign.
`static <V,T extends Throwable> V`	`assign(Try.Assignment<V> assignment, Class<T> throwableClass, String message, Object arg1, Object arg2, Object arg3, Object... args)`	Tries to return a value to assign.
`static <V> V`	`assign(Try.Assignment<V> assignment, String message)`	Tries to return a value to assign.
`static <V> V`	`assign(Try.Assignment<V> assignment, String message, Object arg)`	Tries to return a value to assign.
`static <V> V`	`assign(Try.Assignment<V> assignment, String message, Object arg1, Object arg2)`	Tries to return a value to assign.
`static <V> V`	`assign(Try.Assignment<V> assignment, String message, Object arg1, Object arg2, Object arg3)`	Tries to return a value to assign.
`static <V> V`	`assign(Try.Assignment<V> assignment, String message, Object arg1, Object arg2, Object arg3, Object... args)`	Tries to return a value to assign.
`static <T extends Throwable> void`	`execute(Try.Execution execution, Class<T> throwableClass, String message)`	Tries to execute.
`static <T extends Throwable> void`	`execute(Try.Execution execution, Class<T> throwableClass, String message, Object arg)`	Tries to execute.
`static <T extends Throwable> void`	`execute(Try.Execution execution, Class<T> throwableClass, String message, Object arg1, Object arg2)`	Tries to execute.
`static <T extends Throwable> void`	`execute(Try.Execution execution, Class<T> throwableClass, String message, Object arg1, Object arg2, Object arg3)`	Tries to execute.
`static <T extends Throwable> void`	`execute(Try.Execution execution, Class<T> throwableClass, String message, Object arg1, Object arg2, Object arg3, Object... args)`	Tries to execute.
`static void`	`execute(Try.Execution execution, String message)`	Tries to execute.
`static void`	`execute(Try.Execution execution, String message, Object arg)`	Tries to execute.
`static void`	`execute(Try.Execution execution, String message, Object arg1, Object arg2)`	Tries to execute.
`static void`	`execute(Try.Execution execution, String message, Object arg1, Object arg2, Object arg3)`	Tries to execute.
`static void`	`execute(Try.Execution execution, String message, Object arg1, Object arg2, Object arg3, Object... args)`	Tries to execute.
`static <V> V`	`testFail(Try.Assignment<V> assignment)`	Fails if the assignment succeeds.
`static <V,T extends Throwable> V`	`testFail(Try.Assignment<V> assignment, Class<T> throwableClass)`	Fails if the assignment succeeds.
`static <V> V`	`testFail(Try.Assignment<V> assignment, String message)`	Fails if the assignment succeeds.
`static <V,T extends Throwable> V`	`testFail(Try.Assignment<V> assignment, String message, Class<T> throwableClass)`	Fails if the assignment succeeds.
`static void`	`testFail(Try.Execution execution)`	Fails if the execution succeeds.
`static <T extends Throwable> void`	`testFail(Try.Execution execution, Class<T> throwableClass)`	Fails if the execution succeeds.
`static void`	`testFail(Try.Execution execution, String message)`	Fails if the execution succeeds.
`static <T extends Throwable> void`	`testFail(Try.Execution execution, String message, Class<T> throwableClass)`	Fails if the execution succeeds.
`static <V> V`	`testSucceed(Try.Assignment<V> assignment)`	Fails if the assignment does not succeed.
`static <V,T extends Throwable> V`	`testSucceed(Try.Assignment<V> assignment, Class<T> throwableClass)`	Fails if the assignment does not succeed.
`static <V> V`	`testSucceed(Try.Assignment<V> assignment, String message)`	Fails if the assignment does not succeed.
`static <V,T extends Throwable> V`	`testSucceed(Try.Assignment<V> assignment, String message, Class<T> throwableClass)`	Fails if the assignment does not succeed.
`static void`	`testSucceed(Try.Execution execution)`	Fails if the execution does not succeed.
`static <T extends Throwable> void`	`testSucceed(Try.Execution execution, Class<T> throwableClass)`	Fails if the execution does not succeed.
`static void`	`testSucceed(Try.Execution execution, String message)`	Fails if the execution does not succeed.
`static <T extends Throwable> void`	`testSucceed(Try.Execution execution, String message, Class<T> throwableClass)`	Fails if the execution does not succeed.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

assign
```
public static <V> V assign(Try.Assignment<V> assignment,
                           String message)
                    throws RuntimeException
```
Tries to return a value to assign. Will throw a RuntimeException if the try fails.

Type Parameters:

V - value type

Parameters:

assignment - Assignment<V>; functional interface to assign value

message - String; the message to use in the throwable

Returns:

V; value to assign

Throws:

RuntimeException - on failed Try

assign
```
public static <V> V assign(Try.Assignment<V> assignment,
                           String message,
                           Object arg)
                    throws RuntimeException
```
Tries to return a value to assign. Will throw a RuntimeException if the try fails.

Type Parameters:

V - value type

Parameters:

assignment - Assignment<V>; functional interface to assign value

message - String; the message to use in the throwable, with formatting identifier

arg - Object; value to use for the formatting identifier

Returns:

V; value to assign

Throws:

RuntimeException - on failed Try

assign
```
public static <V> V assign(Try.Assignment<V> assignment,
                           String message,
                           Object arg1,
                           Object arg2)
                    throws RuntimeException
```
Tries to return a value to assign. Will throw a RuntimeException if the try fails.

Type Parameters:

V - value type

Parameters:

assignment - Assignment<V>; functional interface to assign value

message - String; the message to use in the throwable, with formatting identifiers

arg1 - Object; 1st value to use for the formatting identifiers

arg2 - Object; 2nd value to use for the formatting identifiers

Returns:

V; value to assign

Throws:

RuntimeException - on failed Try

assign
```
public static <V> V assign(Try.Assignment<V> assignment,
                           String message,
                           Object arg1,
                           Object arg2,
                           Object arg3)
                    throws RuntimeException
```
Tries to return a value to assign. Will throw a RuntimeException if the try fails.

Type Parameters:

V - value type

Parameters:

assignment - Assignment<V>; functional interface to assign value

message - String; the message to use in the throwable, with formatting identifiers

arg1 - Object; 1st value to use for the formatting identifiers

arg2 - Object; 2nd value to use for the formatting identifiers

arg3 - Object; 3rd value to use for the formatting identifiers

Returns:

V; value to assign

Throws:

RuntimeException - on failed Try

assign
```
public static <V> V assign(Try.Assignment<V> assignment,
                           String message,
                           Object arg1,
                           Object arg2,
                           Object arg3,
                           Object... args)
                    throws RuntimeException
```
Tries to return a value to assign. Will throw a RuntimeException if the try fails.

Type Parameters:

V - value type

Parameters:

assignment - Assignment<V>; functional interface to assign value

message - String; the message to use in the throwable, with formatting identifiers

arg1 - Object; 1st value to use for the formatting identifiers

arg2 - Object; 2nd value to use for the formatting identifiers

arg3 - Object; 3rd value to use for the formatting identifiers

args - Object...; potential 4th and further values to use for the formatting identifiers

Returns:

V; value to assign

Throws:

RuntimeException - on failed Try

assign

public static <V,T extends Throwable> V assign(Try.Assignment<V> assignment,
                                                     Class<T> throwableClass,
                                                     String message)
                                              throws T extends Throwable

Tries to return a value to assign. Will throw a specified Throwable if the try fails.

Type Parameters:: V - value type; T - throwable type
Parameters:: assignment - Assignment<V>; functional interface to assign value; throwableClass - Class<T>; class of the throwable to throw; message - String; the message to use in the throwable
Returns:: V; value to assign
Throws:: T - throwable on failed Try; T extends Throwable

assign

public static <V,T extends Throwable> V assign(Try.Assignment<V> assignment,
                                                     Class<T> throwableClass,
                                                     String message,
                                                     Object arg)
                                              throws T extends Throwable

Tries to return a value to assign. Will throw a specified Throwable if the try fails.

Type Parameters:: V - value type; T - throwable type
Parameters:: assignment - Assignment<V>; functional interface to assign value; throwableClass - Class<T>; class of the throwable to throw; message - String; the message to use in the throwable, with formatting identifier; arg - Object; value to use for the formatting identifier
Returns:: V; value to assign
Throws:: T - throwable on failed Try; T extends Throwable

assign

public static <V,T extends Throwable> V assign(Try.Assignment<V> assignment,
                                                     Class<T> throwableClass,
                                                     String message,
                                                     Object arg1,
                                                     Object arg2)
                                              throws T extends Throwable

Tries to return a value to assign. Will throw a specified Throwable if the try fails.

Type Parameters:: V - value type; T - throwable type
Parameters:: assignment - Assignment<V>; functional interface to assign value; throwableClass - Class<T>; class of the throwable to throw; message - String; the message to use in the throwable, with formatting identifiers; arg1 - Object; 1st value to use for the formatting identifiers; arg2 - Object; 2nd value to use for the formatting identifiers
Returns:: V; value to assign
Throws:: T - throwable on failed Try; T extends Throwable

assign

public static <V,T extends Throwable> V assign(Try.Assignment<V> assignment,
                                                     Class<T> throwableClass,
                                                     String message,
                                                     Object arg1,
                                                     Object arg2,
                                                     Object arg3)
                                              throws T extends Throwable

Tries to return a value to assign. Will throw a specified Throwable if the try fails.

Type Parameters:: V - value type; T - throwable type
Parameters:: assignment - Assignment<V>; functional interface to assign value; throwableClass - Class<T>; class of the throwable to throw; message - String; the message to use in the throwable, with formatting identifiers; arg1 - Object; 1st value to use for the formatting identifiers; arg2 - Object; 2nd value to use for the formatting identifiers; arg3 - Object; 3rd value to use for the formatting identifiers
Returns:: V; value to assign
Throws:: T - throwable on failed Try; T extends Throwable

assign

public static <V,T extends Throwable> V assign(Try.Assignment<V> assignment,
                                                     Class<T> throwableClass,
                                                     String message,
                                                     Object arg1,
                                                     Object arg2,
                                                     Object arg3,
                                                     Object... args)
                                              throws T extends Throwable

Tries to return a value to assign. Will throw a specified Throwable if the try fails.

Type Parameters:: V - value type; T - throwable type
Parameters:: assignment - Assignment<V>; functional interface to assign value; throwableClass - Class<T>; class of the throwable to throw; message - String; the message to use in the throwable, with formatting identifiers; arg1 - Object; 1st value to use for the formatting identifiers; arg2 - Object; 2nd value to use for the formatting identifiers; arg3 - Object; 3rd value to use for the formatting identifiers; args - Object...; potential 4th and further values to use for the formatting identifiers
Returns:: V; value to assign
Throws:: T - throwable on failed Try; T extends Throwable

execute
```
public static void execute(Try.Execution execution,
                           String message)
                    throws RuntimeException
```
Tries to execute. Will throw a RuntimeException if the try fails.

Parameters:

execution - Execution; functional interface to execute

message - String; the message to use in the throwable

Throws:

RuntimeException - on failed Try

execute
```
public static void execute(Try.Execution execution,
                           String message,
                           Object arg)
                    throws RuntimeException
```
Tries to execute. Will throw a RuntimeException if the try fails.

Parameters:

execution - Execution; functional interface to execute

message - String; the message to use in the throwable, with formatting identifier

arg - Object; value to use for the formatting identifier

Throws:

RuntimeException - on failed Try

execute
```
public static void execute(Try.Execution execution,
                           String message,
                           Object arg1,
                           Object arg2)
                    throws RuntimeException
```
Tries to execute. Will throw a RuntimeException if the try fails.

Parameters:

execution - Execution; functional interface to execute

message - String; the message to use in the throwable, with formatting identifiers

arg1 - Object; 1st value to use for the formatting identifiers

arg2 - Object; 2nd value to use for the formatting identifiers

Throws:

RuntimeException - on failed Try

execute
```
public static void execute(Try.Execution execution,
                           String message,
                           Object arg1,
                           Object arg2,
                           Object arg3)
                    throws RuntimeException
```
Tries to execute. Will throw a RuntimeException if the try fails.

Parameters:

execution - Execution; functional interface to execute

message - String; the message to use in the throwable, with formatting identifiers

arg1 - Object; 1st value to use for the formatting identifiers

arg2 - Object; 2nd value to use for the formatting identifiers

arg3 - Object; 3rd value to use for the formatting identifiers

Throws:

RuntimeException - on failed Try

execute
```
public static void execute(Try.Execution execution,
                           String message,
                           Object arg1,
                           Object arg2,
                           Object arg3,
                           Object... args)
                    throws RuntimeException
```
Tries to execute. Will throw a RuntimeException if the try fails.

Parameters:

execution - Execution; functional interface to execute

message - String; the message to use in the throwable, with formatting identifiers

arg1 - Object; 1st value to use for the formatting identifiers

arg2 - Object; 2nd value to use for the formatting identifiers

arg3 - Object; 3rd value to use for the formatting identifiers

args - Object...; potential 4th and further values to use for the formatting identifiers

Throws:

RuntimeException - on failed Try