Merge pull request #8125 from eugenp/revert-8119-BAEL-3275-2

Revert "BAEL-3275: Using blocking queue for pub-sub"

core-java-modules/core-java-io-2/src/main/java/com/baeldung/filereader/FileReaderExample.java

@@ -0,0 +1,57 @@
+package com.baeldung.filereader;
+
+import java.io.*;
+
+public class FileReaderExample {
+
+    public static String readAllCharactersOneByOne(Reader reader) throws IOException {
+        StringBuilder content = new StringBuilder();
+        int nextChar;
+        while ((nextChar = reader.read()) != -1) {
+            content.append((char) nextChar);
+        }
+        return String.valueOf(content);
+    }
+
+    public static String readMultipleCharacters(Reader reader, int length) throws IOException {
+        char[] buffer = new char[length];
+        int charactersRead = reader.read(buffer, 0, length);
+
+
+        if (charactersRead != -1) {
+            return new String(buffer, 0, charactersRead);
+        } else {
+            return "";
+        }
+    }
+
+    public static String readFile(String path) {
+        FileReader fileReader = null;
+        try {
+            fileReader = new FileReader(path);
+            return readAllCharactersOneByOne(fileReader);
+        } catch (IOException e) {
+            e.printStackTrace();
+        } finally {
+            if (fileReader != null) {
+                try {
+                    fileReader.close();
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+            }
+        }
+        return null;
+    }
+
+    public static String readFileUsingTryWithResources(String path) {
+        try (FileReader fileReader = new FileReader(path)) {
+            return readAllCharactersOneByOne(fileReader);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return null;
+    }
+
+
+}

core-java-modules/core-java-io-2/src/main/java/com/baeldung/scanner/HasNextVsHasNextLineDemo.java

@@ -0,0 +1,96 @@
+package com.baeldung.scanner;
+
+import lombok.extern.log4j.Log4j;
+import org.apache.log4j.LogManager;
+import org.apache.log4j.PropertyConfigurator;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Properties;
+import java.util.Scanner;
+
+@Log4j
+public class HasNextVsHasNextLineDemo {
+    private static final String LINE = "----------------------------";
+    private static final String END_LINE = "--------OUTPUT--END---------\n";
+
+
+    private static final String INPUT = new StringBuilder()
+        .append("magic\tproject\n")
+        .append("     database: oracle\n")
+        .append("dependencies:\n")
+        .append("spring:foo:bar\n")
+        .append("\n").toString();
+
+    private static void hasNextBasic() {
+        printHeader("hasNext() Basic");
+        Scanner scanner = new Scanner(INPUT);
+        while (scanner.hasNext()) {
+            log.info(scanner.next());
+        }
+        log.info(END_LINE);
+        scanner.close();
+    }
+
+    private static void hasNextWithDelimiter() {
+        printHeader("hasNext() with delimiter");
+        Scanner scanner = new Scanner(INPUT);
+        while (scanner.hasNext()) {
+            String token = scanner.next();
+            if ("dependencies:".equals(token)) {
+                scanner.useDelimiter(":");
+            }
+            log.info(token);
+        }
+        log.info(END_LINE);
+        scanner.close();
+    }
+
+    private static void hasNextWithDelimiterFixed() {
+        printHeader("hasNext() with delimiter FIX");
+        Scanner scanner = new Scanner(INPUT);
+        while (scanner.hasNext()) {
+            String token = scanner.next();
+            if ("dependencies:".equals(token)) {
+                scanner.useDelimiter(":|\\s+");
+            }
+            log.info(token);
+        }
+        log.info(END_LINE);
+        scanner.close();
+    }
+
+    private static void addLineNumber() {
+        printHeader("add line number by hasNextLine() ");
+        Scanner scanner = new Scanner(INPUT);
+        int i = 0;
+        while (scanner.hasNextLine()) {
+            log.info(String.format("%d|%s", ++i, scanner.nextLine()));
+        }
+        log.info(END_LINE);
+        scanner.close();
+    }
+
+    private static void printHeader(String title) {
+        log.info(LINE);
+        log.info(title);
+        log.info(LINE);
+    }
+
+    public static void main(String[] args) throws IOException {
+        setLogger();
+        hasNextBasic();
+        hasNextWithDelimiter();
+        hasNextWithDelimiterFixed();
+        addLineNumber();
+    }
+
+    //overwrite the logger config
+    private static void setLogger() throws IOException {
+        InputStream is = HasNextVsHasNextLineDemo.class.getResourceAsStream("/scanner/log4j.properties");
+        Properties props = new Properties();
+        props.load(is);
+        LogManager.resetConfiguration();
+        PropertyConfigurator.configure(props);
+    }
+}

core-java-modules/core-java-io-2/src/main/resources/scanner/log4j.properties

@@ -0,0 +1,4 @@
+log4j.rootLogger=INFO, A1
+log4j.appender.A1=org.apache.log4j.ConsoleAppender
+log4j.appender.A1.layout=org.apache.log4j.PatternLayout
+log4j.appender.A1.layout.ConversionPattern=[DEMO]%m%n