BAEL-1044 - Introduction to NoException (#2394)

* BAEL-1044 - Introduction to NoException

* BAEL-1044 - Introduction to NoException

noexception/README.md

@@ -0,0 +1,2 @@
+### Relevant Articles:
+- [Introduction to NoException](http://www.baeldung.com/intrduction-to-noexception)

noexception/pom.xml

@@ -0,0 +1,23 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.baeldung</groupId>
+    <artifactId>noexception</artifactId>
+    <version>1.0</version>
+    <name>noexception</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.machinezoo.noexception</groupId>
+            <artifactId>noexception</artifactId>
+            <version>1.1.0</version>
+        </dependency>
+    </dependencies>
+</project>

noexception/src/main/java/com/baeldung/noexception/CustomExceptionHandler.java

@@ -0,0 +1,24 @@
+package com.baeldung.noexception;
+
+import com.machinezoo.noexception.ExceptionHandler;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class CustomExceptionHandler extends ExceptionHandler {
+
+    private Logger logger = LoggerFactory.getLogger(CustomExceptionHandler.class);
+
+    @Override
+    public boolean handle(Throwable throwable) {
+
+        if (throwable.getClass()
+            .isAssignableFrom(RuntimeException.class)
+            || throwable.getClass()
+                .isAssignableFrom(Error.class)) {
+            return false;
+        } else {
+            logger.error("Caught Exception ", throwable);
+            return true;
+        }
+    }
+}

noexception/src/test/java/com/baeldung/noexception/NoExceptionUnitTest.java

@@ -0,0 +1,63 @@
+package com.baeldung.noexception;
+
+import com.machinezoo.noexception.Exceptions;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class NoExceptionUnitTest {
+
+    private static Logger logger = LoggerFactory.getLogger(NoExceptionUnitTest.class);
+
+    @Test
+    public void whenStdExceptionHandling_thenCatchAndLog() {
+        try {
+            System.out.println("Result is " + Integer.parseInt("foobar"));
+        } catch (Throwable exception) {
+            logger.error("Caught exception:", exception);
+        }
+    }
+
+    @Test
+    public void whenDefaultNoException_thenCatchAndLog() {
+
+        Exceptions.log().run(() -> System.out.println("Result is " + Integer.parseInt("foobar")));
+    }
+
+    @Test
+    public void givenLogger_whenDefaultNoException_thenCatchAndLogWithClassName() {
+        System.out.println("Result is " + Exceptions.log(logger).get(() -> +Integer.parseInt("foobar")).orElse(-1));
+    }
+
+    @Test
+    public void givenLoggerAndMessage_whenDefaultNoException_thenCatchAndLogWithClassNameAndMessage() {
+        System.out.println("Result is " + Exceptions.log(logger, "Something went wrong:").get(() -> +Integer.parseInt("foobar")).orElse(-1));
+    }
+
+    @Test
+    public void givenDefaultValue_whenDefaultNoException_thenCatchAndLogPrintDefault() {
+        System.out.println("Result is " + Exceptions.log(logger, "Something went wrong:").get(() -> +Integer.parseInt("foobar")).orElse(-1));
+    }
+
+    @Test(expected = Error.class)
+    public void givenCustomHandler_whenError_thenRethrowError() {
+        CustomExceptionHandler customExceptionHandler = new CustomExceptionHandler();
+        customExceptionHandler.run(() -> throwError());
+    }
+
+    @Test
+    public void givenCustomHandler_whenException_thenCatchAndLog() {
+        CustomExceptionHandler customExceptionHandler = new CustomExceptionHandler();
+        customExceptionHandler.run(() -> throwException());
+    }
+
+    private static void throwError() {
+        throw new Error("This is very bad.");
+    }
+
+    private static void throwException() {
+        String testString = "foo";
+        testString.charAt(5);
+    }
+
+}

pom.xml

@@ -106,6 +106,7 @@
         <module>mockito2</module>
         <module>mocks</module>
         <module>mustache</module>
+        <module>noexception</module>
 
         <module>orika</module>