1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.id;
18
19 /**
20 * Abstract superclass for StringIdentifierGenerator implementations.
21 *
22 * @author Commons-Id team
23 * @version $Id: AbstractStringIdentifierGenerator.java 480488 2006-11-29 08:57:26Z bayard $
24 */
25 public abstract class AbstractStringIdentifierGenerator implements StringIdentifierGenerator {
26
27 /**
28 * Maximum length for a numeric string representing a long value.
29 */
30 protected static final int MAX_LONG_NUMERIC_VALUE_LENGTH =
31 Long.toString(Long.MIN_VALUE).length();
32
33 /**
34 * Number of alphanumeric characters.
35 */
36 protected static final int ALPHA_NUMERIC_CHARSET_SIZE = 36;
37
38 /**
39 * Maximum length for an alphanumeric string representing a long value.
40 */
41 protected static final int MAX_LONG_ALPHANUMERIC_VALUE_LENGTH =
42 Long.toString(Long.MAX_VALUE, ALPHA_NUMERIC_CHARSET_SIZE).length();
43
44 /**
45 * Maximum length for a numeric string representing an integer value.
46 */
47 protected static final int MAX_INT_NUMERIC_VALUE_LENGTH =
48 Integer.toString(Integer.MIN_VALUE).length();
49
50 /**
51 * Maximum length for an alphanumeric string representing an integer value.
52 */
53 protected static final int MAX_INT_ALPHANUMERIC_VALUE_LENGTH =
54 Integer.toString(Integer.MAX_VALUE, ALPHA_NUMERIC_CHARSET_SIZE).length();
55
56 /**
57 * Default size of an alphanumeric identifier.
58 */
59 protected static final int DEFAULT_ALPHANUMERIC_IDENTIFIER_SIZE = 15;
60
61 /**
62 * Constructor.
63 */
64 protected AbstractStringIdentifierGenerator() {
65 super();
66 }
67
68 public abstract String nextStringIdentifier();
69
70 /**
71 * Returns the maximum length (number or characters) for an identifier
72 * from this sequence.
73 *
74 * <p>The default implementation returns {@link #INFINITE_MAX_LENGTH}. Implementations
75 * with bounded length identifiers should override this method to
76 * return the maximum length of a generated identifier.</p>
77 *
78 * @return {@inheritDoc}
79 */
80 public long maxLength() {
81 return INFINITE_MAX_LENGTH;
82 }
83
84 /**
85 * Returns the minimum length (number of characters) for an identifier
86 * from this sequence.
87 *
88 * <p>The default implementation returns 0. Implementations
89 * with identifiers having a postive minimum length should override this
90 * method to return the maximum length of a generated identifier.</p>
91 *
92 * @return {@inheritDoc}
93 */
94 public long minLength() {
95 return 0;
96 }
97
98 public Object nextIdentifier() {
99 return nextStringIdentifier();
100 }
101 }