/*
 * Copyright (c) 2003, 2023, 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
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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package java.lang;

import java.io.IOException;

/**
 * A {@code Readable} is a source of characters. Characters from
 * a {@code Readable} are made available to callers of the read
 * method via a {@link java.nio.CharBuffer CharBuffer}.
 *
 * @since 1.5
 */
public interface Readable {

    /**
     * Attempts to read characters into the specified character buffer.
     * The buffer is used as a repository of characters as-is: the only
     * changes made are the results of a put operation. No flipping or
     * rewinding of the buffer is performed. If the {@linkplain
     * java.nio.CharBuffer#length length} of the specified character
     * buffer is zero, then no characters will be read and zero will be
     * returned.
     *
     * @param cb the buffer to read characters into
     * @return The number of {@code char} values added to the buffer,
     *         possibly zero, or -1 if this source of characters is at its end
     * @throws IOException if an I/O error occurs
     * @throws NullPointerException if cb is null
     * @throws java.nio.ReadOnlyBufferException if cb is a read only buffer,
     *         even if its length is zero
     */
    public int read(java.nio.CharBuffer cb) throws IOException;
}