80 lines
2.3 KiB
Java
80 lines
2.3 KiB
Java
// concurrent/CatchCompletableExceptions.java
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// (c)2016 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://OnJava8.com for more book information.
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import java.util.concurrent.*;
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import onjava.Nap;
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public class CatchCompletableExceptions {
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static void handleException(int failcount) {
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// Call Function only if there's an exception,
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// Must produce same type as came in:
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CompletableExceptions
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.test("exceptionally", failcount)
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.exceptionally((ex) -> { // Function
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if(ex == null)
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System.out.println("I don't get it yet");
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return new Breakable(ex.getMessage(), 0);
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})
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.thenAccept(str ->
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System.out.println("result: " + str));
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// Create a new result (recover):
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CompletableExceptions
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.test("handle", failcount)
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.handle((result, fail) -> { // BiFunction
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if(fail != null)
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return "Failure recovery object";
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else
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return result + " is good";
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})
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.thenAccept(str ->
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System.out.println("result: " + str));
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// Do something but pass the same result through:
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CompletableExceptions
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.test("whenComplete", failcount)
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.whenComplete((result, fail) -> { // BiConsumer
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if(fail != null)
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System.out.println("It failed");
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else
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System.out.println(result + " OK");
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})
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.thenAccept(r ->
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System.out.println("result: " + r));
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}
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public static void main(String[] args) {
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System.out.println("**** Failure Mode ****");
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handleException(2);
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System.out.println("**** Success Mode ****");
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handleException(0);
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}
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}
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/* Output:
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**** Failure Mode ****
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Breakable_exceptionally [1]
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result: Breakable_java.lang.RuntimeException:
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Breakable_exceptionally failed [0]
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Breakable_handle [1]
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result: Failure recovery object
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Breakable_whenComplete [1]
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It failed
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**** Success Mode ****
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Breakable_exceptionally [-1]
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Breakable_exceptionally [-2]
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Breakable_exceptionally [-3]
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Breakable_exceptionally [-4]
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result: Breakable_exceptionally [-4]
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Breakable_handle [-1]
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Breakable_handle [-2]
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Breakable_handle [-3]
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Breakable_handle [-4]
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result: Breakable_handle [-4] is good
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Breakable_whenComplete [-1]
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Breakable_whenComplete [-2]
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Breakable_whenComplete [-3]
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Breakable_whenComplete [-4]
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Breakable_whenComplete [-4] OK
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result: Breakable_whenComplete [-4]
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*/
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