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src/java.base/share/classes/java/lang/Readable.java

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   1 /*
   2  * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.lang;
  27 
  28 import java.io.IOException;


  29 
  30 /**
  31  * A {@code Readable} is a source of characters. Characters from
  32  * a {@code Readable} are made available to callers of the read
  33  * method via a {@link java.nio.CharBuffer CharBuffer}.
  34  *
  35  * @since 1.5
  36  */
  37 public interface Readable {
  38 
  39     /**
  40      * Attempts to read characters into the specified character buffer.
  41      * The buffer is used as a repository of characters as-is: the only
  42      * changes made are the results of a put operation. No flipping or
  43      * rewinding of the buffer is performed.
  44      *
  45      * @param cb the buffer to read characters into
  46      * @return The number of {@code char} values added to the buffer,
  47      *                 or -1 if this source of characters is at its end
  48      * @throws IOException if an I/O error occurs
  49      * @throws NullPointerException if cb is null
  50      * @throws java.nio.ReadOnlyBufferException if cb is a read only buffer
  51      */
  52     public int read(java.nio.CharBuffer cb) throws IOException;







































  53 }
   1 /*
   2  * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.lang;
  27 
  28 import java.io.IOException;
  29 import java.nio.CharBuffer;
  30 import java.util.Objects;
  31 
  32 /**
  33  * A {@code Readable} is a source of characters. Characters from
  34  * a {@code Readable} are made available to callers of the read
  35  * method via a {@link java.nio.CharBuffer CharBuffer}.
  36  *
  37  * @since 1.5
  38  */
  39 public interface Readable {
  40 
  41     /**
  42      * Attempts to read characters into the specified character buffer.
  43      * The buffer is used as a repository of characters as-is: the only
  44      * changes made are the results of a put operation. No flipping or
  45      * rewinding of the buffer is performed.
  46      *
  47      * @param cb the buffer to read characters into
  48      * @return The number of {@code char} values added to the buffer,
  49      *                 or -1 if this source of characters is at its end
  50      * @throws IOException if an I/O error occurs
  51      * @throws NullPointerException if cb is null
  52      * @throws java.nio.ReadOnlyBufferException if cb is a read only buffer
  53      */
  54     public int read(java.nio.CharBuffer cb) throws IOException;
  55 
  56     /**
  57      * Reads all characters from this source and writes the characters to
  58      * the given appendable in the order that they are read. On return, the
  59      * source of characters will be at its end.
  60      * <p>
  61      * This method may block indefinitely reading from the readable, or
  62      * writing to the appendable. Where this source or the appendable is
  63      * {@link AutoCloseable closeable}, then the behavior when either are
  64      * <i>asynchronously closed</i>, or the thread interrupted during the transfer,
  65      * is highly readable and appendable specific, and therefore not specified.
  66      * <p>
  67      * If an I/O error occurs reading from the readable or writing to the
  68      * appendable, then it may do so after some characters have been read or
  69      * written. Consequently the readable may not be at end of its data and
  70      * one, or both participants may be in an inconsistent state. That in mind
  71      * all additional measures required by one or both participants in order to
  72      * eventually free their internal resources have to be taken by the caller
  73      * of this method.
  74      *
  75      * @param  out the appendable, non-null
  76      * @return the number of characters transferred
  77      * @throws IOException if an I/O error occurs when reading or writing
  78      * @throws NullPointerException if {@code out} is {@code null}
  79      *
  80      * @since 10
  81      */
  82     public default long transferTo(Appendable out) throws IOException {
  83         Objects.requireNonNull(out, "out");
  84         long transferred = 0;
  85         CharBuffer buffer = CharBuffer.allocate(8192);
  86         int read;
  87         while ((read = this.read(buffer)) >= 0) {
  88             buffer.rewind();
  89             out.append(buffer, 0, read);
  90             transferred += read;
  91         }
  92         return transferred;
  93     }
  94 }
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