src/share/classes/java/io/BufferedReader.java

rev 7006 : 8003258: BufferedReader.lines()
Reviewed-by:

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 1996, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this

@@ -24,10 +24,17 @@
  */
 
 package java.io;
 
 
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+import java.util.Spliterator;
+import java.util.Spliterators;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
 /**
  * Reads text from a character-input stream, buffering characters so as to
  * provide for the efficient reading of characters, arrays, and lines.
  *
  * <p> The buffer size may be specified, or the default size may be used.  The

@@ -520,6 +527,63 @@
                 in = null;
                 cb = null;
             }
         }
     }
+
+    /**
+     * Returns a {@code Stream}, the elements of which are lines read from this
+     * {@code BufferedReader}.  The {@link Stream} is lazily populated via
+     * calls to {@link #readLine()}.
+     *
+     * <p>Each element consumed by the {@code Stream} caused a line to be
+     * read from this {@code BufferedReader}. Since the {@code Stream} does
+     * not necessary consume all lines, it is possible to mix and use
+     * different read methods on a {@code BufferedReader}. Each method will
+     * simply pick up from where it was left on last read.
+     *
+     * <p>If an {@link IOException} is thrown when accessing the underlying
+     * {@code BufferedReader}, it is wrapped in an {@link
+     * UncheckedIOException} which will be thrown from the {@code Stream}
+     * method that caused the read to take place. For example, when trying to
+     * read from the {@code Stream} after the {@code BufferedReader} is
+     * closed, will throw an {@code UnchecheckedIOException}.
+     *
+     * @return a {@code Stream<String>} providing the lines of text
+     *         described by this {@code BufferedReader}
+     *
+     * @since 1.8
+     */
+    public Stream<String> lines() {
+        Iterator<String> iter = new Iterator<String>() {
+            String nextLine = null;
+
+            @Override
+            public boolean hasNext() {
+                if (nextLine != null) {
+                    return true;
+                } else {
+                    try {
+                        nextLine = readLine();
+                        return (nextLine != null);
+                    } catch (IOException e) {
+                        throw new UncheckedIOException(e);
+                    }
+                }
+            }
+
+            @Override
+            public String next() {
+                if (nextLine != null || hasNext()) {
+                    try {
+                        return nextLine;
+                    } finally {
+                        nextLine = null;
+                    }
+                } else {
+                    throw new NoSuchElementException();
+                }
+            }
+        };
+        return StreamSupport.stream(Spliterators.spliteratorUnknownSize(iter, Spliterator.ORDERED));
+    }
 }