Merge pull request #7910 from mnafshin/MalformedInputException

[BAEL-2505] MalformedInputException test functions are added

core-java-modules/core-java/src/main/java/com/baeldung/encoding/CharacterEncodingExamples.java

@@ -1,10 +1,15 @@
 package com.baeldung.encoding;
 
+import java.io.BufferedReader;
+import java.io.ByteArrayInputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.UnsupportedEncodingException;
+import java.nio.charset.Charset;
+import java.nio.charset.CharsetDecoder;
+import java.nio.charset.CodingErrorAction;
 
 public class CharacterEncodingExamples {
 
@@ -29,4 +34,12 @@ public class CharacterEncodingExamples {
         }
         return buffer.toString();
     }
+
+    static String decodeText(String input, Charset charset, CodingErrorAction codingErrorAction) throws IOException {
+        CharsetDecoder charsetDecoder = charset.newDecoder();
+        charsetDecoder.onMalformedInput(codingErrorAction);
+        return new BufferedReader(
+          new InputStreamReader(
+            new ByteArrayInputStream(input.getBytes()), charsetDecoder)).readLine();
+    }
 }

core-java-modules/core-java/src/test/java/com/baeldung/encoding/CharacterEncodingExamplesUnitTest.java

@@ -1,9 +1,24 @@
 package com.baeldung.encoding;
 
+import java.io.BufferedReader;
 import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.nio.charset.Charset;
+import java.nio.charset.CharsetDecoder;
+import java.nio.charset.CodingErrorAction;
+import java.nio.charset.MalformedInputException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
 
 import org.junit.Assert;
 import org.junit.Test;
+import org.junit.jupiter.api.Assertions;
 
 public class CharacterEncodingExamplesUnitTest {
 
@@ -58,4 +73,52 @@ public class CharacterEncodingExamplesUnitTest {
           "0 0 10001010 10011110 ");
     }
 
+    @Test
+    public void givenUTF8String_whenDecodeByUS_ASCII_thenIgnoreMalformedInputSequence() throws IOException {
+        Assertions.assertEquals("The faade pattern is a software design pattern.", CharacterEncodingExamples.decodeText("The façade pattern is a software design pattern.", StandardCharsets.US_ASCII, CodingErrorAction.IGNORE));
+    }
+
+    @Test
+    public void givenUTF8String_whenDecodeByUS_ASCII_thenReplaceMalformedInputSequence() throws IOException {
+        Assertions.assertEquals(
+          "The fa<66><61>ade pattern is a software design pattern.",
+          CharacterEncodingExamples.decodeText(
+            "The façade pattern is a software design pattern.",
+            StandardCharsets.US_ASCII,
+            CodingErrorAction.REPLACE));
+    }
+
+    @Test
+    public void givenUTF8String_whenDecodeByUS_ASCII_thenReportMalformedInputSequence() {
+        Assertions.assertThrows(
+          MalformedInputException.class,
+          () -> CharacterEncodingExamples.decodeText(
+            "The façade pattern is a software design pattern.",
+            StandardCharsets.US_ASCII,
+            CodingErrorAction.REPORT));
+    }
+
+    @Test
+    public void givenTextFile_whenLoopOverAllCandidateEncodings_thenProduceSuitableCandidateEncodings() {
+        Path path = Paths.get("src/test/resources/encoding.txt");
+        List<Charset> allCandidateCharSets = Arrays.asList(
+          StandardCharsets.US_ASCII, StandardCharsets.UTF_8, StandardCharsets.ISO_8859_1);
+
+        List<Charset> suitableCharsets = new ArrayList<>();
+        allCandidateCharSets.forEach(charset -> {
+            try {
+                CharsetDecoder charsetDecoder = charset.newDecoder().onMalformedInput(CodingErrorAction.REPORT);
+                Reader reader = new InputStreamReader(Files.newInputStream(path), charsetDecoder);
+                BufferedReader bufferedReader = new BufferedReader(reader);
+                bufferedReader.readLine();
+                suitableCharsets.add(charset);
+            } catch (MalformedInputException ignored) {
+            } catch (IOException ex) {
+                ex.printStackTrace();
+            }
+        });
+
+        Assertions.assertEquals(suitableCharsets, Arrays.asList(StandardCharsets.UTF_8, StandardCharsets.ISO_8859_1));
+    }
+
 }