Code: Utf8LineInputStream, SourceLocation, SourceManager

Main.java

@@ -1,5 +1,8 @@
 package org.duangsuse.telegramscanner;
 
+import org.duangsuse.telegramscanner.scanner.Utf8LineInputStream;
+
+import java.io.IOException;
 import java.io.PrintStream;
 
 /**
@@ -33,5 +36,19 @@ private Main() {}
      */
     public static void main(String... args) {
         err.print("TelegramScanner version "); err.println(VERSION);
+
+        Utf8LineInputStream input = new Utf8LineInputStream(System.in);
+        String line = "";
+
+        try {
+            do {
+                out.print(line);
+                out.println();
+                out.print("> ");
+            }
+            while ((line = input.readLine()) != null);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
     }
 }

scanner/Utf8LineInputStream.java

@@ -0,0 +1,114 @@
+package org.duangsuse.telegramscanner.scanner;
+
+import java.io.*;
+import java.nio.charset.Charset;
+
+/**
+ * Line based input stream
+ *
+ * @see java.io.DataInput
+ * @see java.io.InputStream
+ */
+public class Utf8LineInputStream implements Closeable {
+    /**
+     * Delegated data input stream
+     */
+    private DataInput target;
+
+    /**
+     * Construct using data input {@link DataInputStream}
+     *
+     * @param dataIn data input instance
+     */
+    public Utf8LineInputStream(DataInput dataIn) {
+        this.target = dataIn;
+    }
+
+    /**
+     * Construct using byte input stream
+     *
+     * @see InputStreamReader with utf-8 decoder support
+     * @param in line-based input stream
+     */
+    public Utf8LineInputStream(InputStream in) {
+        final InputStreamReader utf8InputReader = new InputStreamReader(in, UTF_8);
+        InputStream is = new InputStream() {
+            @Override
+            public int read() throws IOException {
+                return utf8InputReader.read();
+            } /* readLine() uses this method only */
+        };
+
+        this.target = new DataInputStream(is);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        Utf8LineInputStream that = (Utf8LineInputStream) o;
+
+        return target.equals(that.target);
+    }
+
+    /**
+     * Utf-8 charset
+     */
+    @SuppressWarnings("WeakerAccess")
+    protected static final Charset UTF_8 = Charset.forName("UTF-8");
+
+    /**
+     * Reads the next line of text from the input stream.
+     * It reads successive bytes, converting
+     * each byte separately into a character,
+     * until it encounters a line terminator or
+     * end of
+     * file; the characters read are then
+     * returned as a {@code String}. Note
+     * that because this
+     * method processes bytes,
+     * <b>it does not support input of the full Unicode
+     * character set.</b>
+     * <p>
+     * If end of file is encountered
+     * before even one byte can be read, then {@code null}
+     * is returned. Otherwise, each byte that is
+     * read is converted to type {@code char}
+     * by zero-extension. If the character {@code '\n'}
+     * is encountered, it is discarded and reading
+     * ceases. If the character {@code '\r'}
+     * is encountered, it is discarded and, if
+     * the following byte converts &#32;to the
+     * character {@code '\n'}, then that is
+     * discarded also; reading then ceases. If
+     * end of file is encountered before either
+     * of the characters {@code '\n'} and
+     * {@code '\r'} is encountered, reading
+     * ceases. Once reading has ceased, a {@code String}
+     * is returned that contains all the characters
+     * read and not discarded, taken in order.
+     * Note that every character in this string
+     * will have a value less than {@code \u005Cu0100},
+     * that is, {@code (char)256}.
+     *
+     * @return the next line of text from the input stream,
+     *         or {@code null} if the end of file is
+     *         encountered before a byte can be read.
+     * @exception  IOException  if an I/O error occurs.
+     */
+    public String readLine() throws IOException {
+        return target.readLine();
+    }
+
+    @Override
+    public void close() throws IOException {
+        if (target instanceof Closeable)
+            ((Closeable) target).close();
+    }
+
+    @Override
+    public String toString() {
+        return "Utf8LineInputStream(" + target.toString() + ")";
+    }
+}

sourcemanager/SourceLocation.java

@@ -28,7 +28,7 @@ public SourceLocation() {
     }
 
     public SourceLocation(int offset, int line, int messageNo, int messageLine) {
-        super();
+        super(); // ;)
         this.offset = offset;
         this.line = line;
         this.messageNo = messageNo;
@@ -75,10 +75,6 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        final StringBuilder sb = new StringBuilder("SourceLocation");
-        sb.append('(').append('@').append(offset).append('L').append(line)
-                .append(", Message#").append(messageNo).append(':').append(messageLine).append(')');
-
-        return sb.toString();
+        return String.format("SourceLocation(@%dL%d, Message#%d:%d)", offset, line, messageNo, messageLine);
     }
 }

sourcemanager/SourceManager.java

@@ -17,7 +17,8 @@ public SourceManager() {
      * Lazy source manager singleton instance
      */
     private static final class LazyHolder {
-        static final SourceManager INSTANCE = new SourceManager();
+        /** Initialized in <clinit> */static final SourceManager INSTANCE;
+        static { INSTANCE = new SourceManager(); }
     }
 
     public SourceManager getInstance() { return LazyHolder.INSTANCE; }