Appendable.java revision f33eae7e84eb6d3b0f4e86b59605bb3de73009f3 
1/* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements.  See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License.  You may obtain a copy of the License at
7 *
8 *     http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package java.lang;
18
19import java.io.IOException;
20
21/**
22 * Declares methods to append characters or character sequences. Any class that
23 * implements this interface can receive data formatted by a
24 * {@link java.util.Formatter}. The appended character or character sequence
25 * should be valid according to the rules described in
26 * {@link Character Unicode Character Representation}.
27 * <p>
28 * {@code Appendable} itself does not guarantee thread safety. This
29 * responsibility is up to the implementing class.
30 * <p>
31 * Implementing classes can choose different exception handling mechanism. They
32 * can choose to throw exceptions other than {@code IOException} or they do not
33 * throw any exceptions at all and use error codes instead.
34 */
35public interface Appendable {
36
37    /**
38     * Appends the specified character.
39     *
40     * @param c
41     *            the character to append.
42     * @return this {@code Appendable}.
43     * @throws IOException
44     *             if an I/O error occurs.
45     */
46    Appendable append(char c) throws IOException;
47
48    /**
49     * Appends the character sequence {@code csq}. Implementation classes may
50     * not append the whole sequence, for example if the target is a buffer with
51     * limited size.
52     * <p>
53     * If {@code csq} is {@code null}, the characters "null" are appended.
54     *
55     * @param csq
56     *            the character sequence to append.
57     * @return this {@code Appendable}.
58     * @throws IOException
59     *             if an I/O error occurs.
60     */
61    Appendable append(CharSequence csq) throws IOException;
62
63    /**
64     * Appends a subsequence of {@code csq}.
65     * <p>
66     * If {@code csq} is not {@code null} then calling this method is equivalent
67     * to calling {@code append(csq.subSequence(start, end))}.
68     * <p>
69     * If {@code csq} is {@code null}, the characters "null" are appended.
70     *
71     * @param csq
72     *            the character sequence to append.
73     * @param start
74     *            the first index of the subsequence of {@code csq} that is
75     *            appended.
76     * @param end
77     *            the last index of the subsequence of {@code csq} that is
78     *            appended.
79     * @return this {@code Appendable}.
80     * @throws IndexOutOfBoundsException
81     *             if {@code start < 0}, {@code end < 0}, {@code start > end}
82     *             or {@code end} is greater than the length of {@code csq}.
83     * @throws IOException
84     *             if an I/O error occurs.
85     */
86    Appendable append(CharSequence csq, int start, int end) throws IOException;
87}
88