Adding files for Exception Handling article (#4507)
* Adding files for Exception Handling article * Updating files * Test folder * testing renaming * Formatting and Naming Conventions This commit reworks the code for the Intro to Exception Handling article, ensuring that packages and classes are formatted and named according to site standards.
This commit is contained in:
DavidLandup
Josh Cummings
parent
815f655f36
commit
0b642f91e0
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package com.baeldung.exceptionhandling;
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import java.io.File;
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import java.io.FileNotFoundException;
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import java.io.IOException;
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import java.nio.file.Files;
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import java.nio.file.Path;
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import java.nio.file.Paths;
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import java.util.List;
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import java.util.Scanner;
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import java.util.logging.Logger;
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import java.util.stream.Collectors;
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public class Exceptions {
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private final static Logger logger = Logger.getLogger("ExceptionLogging");
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public static List<Player> getPlayers() throws IOException {
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Path path = Paths.get("players.dat");
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List<String> players = Files.readAllLines(path);
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return players.stream()
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.map(Player::new)
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.collect(Collectors.toList());
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}
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public List<Player> loadAllPlayers(String playersFile) throws IOException{
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try {
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throw new IOException();
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} catch(IOException ex) {
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throw new IllegalStateException();
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}
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}
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public int getPlayerScoreThrows(String playerFile) throws FileNotFoundException {
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Scanner contents = new Scanner(new File(playerFile));
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return Integer.parseInt(contents.nextLine());
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}
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public int getPlayerScoreTryCatch(String playerFile) {
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try {
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Scanner contents = new Scanner(new File(playerFile));
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return Integer.parseInt(contents.nextLine());
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} catch (FileNotFoundException noFile) {
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throw new IllegalArgumentException("File not found");
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}
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}
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public int getPlayerScoreTryCatchRecovery(String playerFile) {
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try {
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Scanner contents = new Scanner(new File(playerFile));
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return Integer.parseInt(contents.nextLine());
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} catch ( FileNotFoundException noFile ) {
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logger.warning("File not found, resetting score.");
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return 0;
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}
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}
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public int getPlayerScoreFinally(String playerFile) throws FileNotFoundException {
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Scanner contents = null;
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try {
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contents = new Scanner(new File(playerFile));
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return Integer.parseInt(contents.nextLine());
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} finally {
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if (contents != null) {
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contents.close();
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}
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}
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}
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public int getPlayerScoreTryWithResources(String playerFile) {
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try (Scanner contents = new Scanner(new File(playerFile))) {
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return Integer.parseInt(contents.nextLine());
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} catch (FileNotFoundException e ) {
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logger.warning("File not found, resetting score.");
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return 0;
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}
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}
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public int getPlayerScoreMultipleCatchBlocks(String playerFile) {
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try (Scanner contents = new Scanner(new File(playerFile))) {
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return Integer.parseInt(contents.nextLine());
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} catch (IOException e) {
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logger.warning("Player file wouldn't load!");
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return 0;
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} catch (NumberFormatException e) {
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logger.warning("Player file was corrupted!");
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return 0;
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}
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}
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public int getPlayerScoreMultipleCatchBlocksAlternative(String playerFile) {
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try (Scanner contents = new Scanner(new File(playerFile)) ) {
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return Integer.parseInt(contents.nextLine());
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} catch (FileNotFoundException e) {
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logger.warning("Player file not found!");
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return 0;
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} catch (IOException e) {
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logger.warning("Player file wouldn't load!");
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return 0;
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} catch (NumberFormatException e) {
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logger.warning("Player file was corrupted!");
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return 0;
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}
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}
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public int getPlayerScoreUnionCatchBlocks(String playerFile) {
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try (Scanner contents = new Scanner(new File(playerFile))) {
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return Integer.parseInt(contents.nextLine());
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} catch (IOException | NumberFormatException e) {
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logger.warning("Failed to load score!");
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return 0;
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}
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}
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public List<Player> loadAllPlayersThrowingChecked(String playersFile) throws TimeoutException {
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boolean tooLong = true;
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while (!tooLong) {
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// ... potentially long operation
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}
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throw new TimeoutException("This operation took too long");
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}
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public List<Player> loadAllPlayersThrowingUnchecked(String playersFile) throws TimeoutException {
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if(!isFilenameValid(playersFile)) {
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throw new IllegalArgumentException("Filename isn't valid!");
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}
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return null;
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// ...
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}
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public List<Player> loadAllPlayersWrapping(String playersFile) throws IOException {
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try {
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throw new IOException();
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} catch (IOException io) {
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throw io;
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}
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}
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public List<Player> loadAllPlayersRethrowing(String playersFile) throws PlayerLoadException {
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try {
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throw new IOException();
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} catch (IOException io) {
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throw new PlayerLoadException(io);
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}
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}
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public List<Player> loadAllPlayersThrowable(String playersFile) {
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try {
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throw new NullPointerException();
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} catch ( Throwable t ) {
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throw t;
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}
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}
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class FewerExceptions extends Exceptions {
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@Override
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public List<Player> loadAllPlayers(String playersFile) { //can't add "throws MyCheckedException
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return null;
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// overridden
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}
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}
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public void throwAsGotoAntiPattern() {
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try {
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// bunch of code
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throw new MyException();
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// second bunch of code
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} catch ( MyException e ) {
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// third bunch of code
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}
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}
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public int getPlayerScoreSwallowingExceptionAntiPattern(String playerFile) {
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try {
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// ...
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} catch (Exception e) {} // <== catch and swallow
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return 0;
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}
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public int getPlayerScoreSwallowingExceptionAntiPatternAlternative(String playerFile) {
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try {
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// ...
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} catch (Exception e) {
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e.printStackTrace();
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}
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return 0;
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}
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public int getPlayerScoreSwallowingExceptionAntiPatternAlternative2(String playerFile) throws PlayerScoreException {
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try {
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throw new IOException();
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} catch (IOException e) {
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throw new PlayerScoreException(e);
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}
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}
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public int getPlayerScoreReturnInFinallyAntiPattern(String playerFile) {
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int score = 0;
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try {
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throw new IOException();
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} finally {
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return score; // <== the IOException is dropped
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}
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}
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private boolean isFilenameValid(String name) {
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return false;
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}
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}
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@ -0,0 +1,5 @@
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package com.baeldung.exceptionhandling;
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public class MyException extends Throwable {
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}
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@ -0,0 +1,12 @@
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package com.baeldung.exceptionhandling;
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public class Player {
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public int id;
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public String name;
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public Player(String name) {
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this.name = name;
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}
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}
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@ -0,0 +1,11 @@
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package com.baeldung.exceptionhandling;
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import java.io.IOException;
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public class PlayerLoadException extends Exception {
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public PlayerLoadException(IOException io) {
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super(io);
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}
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}
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@ -0,0 +1,8 @@
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package com.baeldung.exceptionhandling;
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public class PlayerScoreException extends Exception {
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public PlayerScoreException(Exception e) {
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super(e);
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}
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}
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@ -0,0 +1,8 @@
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package com.baeldung.exceptionhandling;
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public class TimeoutException extends Exception {
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public TimeoutException(String message) {
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super(message);
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}
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}
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@ -0,0 +1,86 @@
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package com.baeldung.exceptionhandling;
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import org.junit.Test;
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import java.io.FileNotFoundException;
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import java.io.IOException;
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import java.nio.file.NoSuchFileException;
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import static org.assertj.core.api.Assertions.assertThatThrownBy;
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public class ExceptionsUnitTest {
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Exceptions exceptions = new Exceptions();
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@Test
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public void getPlayers() {
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assertThatThrownBy(() -> exceptions.getPlayers())
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.isInstanceOf(NoSuchFileException.class);
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}
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@Test
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public void loadAllPlayers() {
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assertThatThrownBy(() -> exceptions.loadAllPlayers(""))
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.isInstanceOf(IOException.class);
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}
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@Test
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public void getPlayerScoreThrows() {
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assertThatThrownBy(() -> exceptions.getPlayerScoreThrows(""))
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.isInstanceOf(FileNotFoundException.class);
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}
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@Test
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public void getPlayerScoreTryCatch() {
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assertThatThrownBy(() -> exceptions.getPlayerScoreTryCatch(""))
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.isInstanceOf(IllegalArgumentException.class);
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}
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@Test
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public void getPlayerScoreFinally() {
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assertThatThrownBy(() -> exceptions.getPlayerScoreFinally(""))
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.isInstanceOf(FileNotFoundException.class);
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}
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@Test
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public void loadAllPlayersThrowingChecked() {
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assertThatThrownBy(() -> exceptions.loadAllPlayersThrowingChecked(""))
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.isInstanceOf(TimeoutException.class);
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}
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@Test
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public void loadAllPlayersThrowingUnchecked() {
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assertThatThrownBy(() -> exceptions.loadAllPlayersThrowingUnchecked(""))
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.isInstanceOf(IllegalArgumentException.class);
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}
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@Test
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public void loadAllPlayersWrapping() {
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assertThatThrownBy(() -> exceptions.loadAllPlayersWrapping(""))
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.isInstanceOf(IOException.class);
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}
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@Test
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public void loadAllPlayersRethrowing() {
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assertThatThrownBy(() -> exceptions.loadAllPlayersRethrowing(""))
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.isInstanceOf(PlayerLoadException.class);
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}
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@Test
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public void loadAllPlayersThrowable() {
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assertThatThrownBy(() -> exceptions.loadAllPlayersThrowable(""))
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.isInstanceOf(NullPointerException.class);
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}
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@Test
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public void throwAsGotoAntiPattern() {
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assertThatThrownBy(() -> exceptions.throwAsGotoAntiPattern())
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.isInstanceOf(MyException.class);
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}
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@Test
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public void getPlayerScoreSwallowingExceptionAntiPatternAlternative2() {
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assertThatThrownBy(() -> exceptions.getPlayerScoreSwallowingExceptionAntiPatternAlternative2(""))
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.isInstanceOf(PlayerScoreException.class);
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}
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}
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