001 /*
002 * The MIT License
003 *
004 * Copyright (c) 2013, Ninja Squad
005 *
006 * Permission is hereby granted, free of charge, to any person obtaining a copy
007 * of this software and associated documentation files (the "Software"), to deal
008 * in the Software without restriction, including without limitation the rights
009 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
010 * copies of the Software, and to permit persons to whom the Software is
011 * furnished to do so, subject to the following conditions:
012 *
013 * The above copyright notice and this permission notice shall be included in
014 * all copies or substantial portions of the Software.
015 *
016 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
017 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
018 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
019 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
020 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
021 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
022 * THE SOFTWARE.
023 */
024
025 package com.ninja_squad.dbsetup.generator;
026
027 import com.ninja_squad.dbsetup.util.Preconditions;
028
029 /**
030 * A {@link ValueGenerator} that returns a string prefix followed by a sequence number, optionally left-padded
031 * with 0 to ensure a correct ordering (for example: CODE_001, CODE_002, etc.). Instances of this generator
032 * are created by {@link ValueGenerators#stringSequence(String)}.
033 * @author JB
034 */
035 public final class StringSequenceValueGenerator implements ValueGenerator<String> {
036 private String prefix;
037 private long next;
038 private int increment;
039
040 /**
041 * The length of the number once padded. 0 if no padding must be applied
042 */
043 private int paddedNumberLength;
044
045 StringSequenceValueGenerator(String prefix) {
046 this(prefix, 1L, 1, 0);
047 }
048
049 private StringSequenceValueGenerator(String prefix, long next, int increment, int paddedNumberLength) {
050 this.prefix = prefix;
051 this.next = next;
052 this.increment = increment;
053 this.paddedNumberLength = paddedNumberLength;
054 }
055
056 /**
057 * Tells the generator to left-pad the number it generates with 0 until the length of the number is the given
058 * length. For example, passing 3 to this method will generate numbers 001, 002, 003, 004, etc. If the generated
059 * number, before padding, has a length already equal or larger that the given length, the number is not padded.
060 * @param paddedNumberLength the length of the number once padded. Must be > 0.
061 * @return this instance, for chaining
062 */
063 public StringSequenceValueGenerator withLeftPadding(int paddedNumberLength) {
064 Preconditions.checkArgument(paddedNumberLength > 0, "paddedNumberLength must be > 0");
065 this.paddedNumberLength = paddedNumberLength;
066 return this;
067 }
068
069 /**
070 * Tells the generator to avoid left-padding the number it generates with 0
071 * @return this instance, for chaining
072 */
073 public StringSequenceValueGenerator withoutLeftPadding() {
074 this.paddedNumberLength = 0;
075 return this;
076 }
077
078 /**
079 * Restarts the sequence at the given value
080 * @param start the new starting value of the sequence
081 * @return this instance, for chaining
082 */
083 public StringSequenceValueGenerator startingAt(long start) {
084 this.next = start;
085 return this;
086 }
087
088 /**
089 * Increments the number by the given increment.
090 * @return this instance, for chaining
091 */
092 public StringSequenceValueGenerator incrementingBy(int increment) {
093 this.increment = increment;
094 return this;
095 }
096
097 @Override
098 public String nextValue() {
099 long number = next;
100 next += increment;
101 return prefix + leftPadIfNecessary(number);
102 }
103
104 private String leftPadIfNecessary(long number) {
105 String numberAsString = Long.toString(number);
106 if (numberAsString.length() >= paddedNumberLength) {
107 return numberAsString;
108 }
109 StringBuilder builder = new StringBuilder(paddedNumberLength);
110 for (int i = 0; i < paddedNumberLength - numberAsString.length(); i++) {
111 builder.append('0');
112 }
113 return builder.append(numberAsString).toString();
114 }
115
116 @Override
117 public String toString() {
118 return "StringSequenceValueGenerator["
119 + "prefix='" + prefix + '\''
120 + ", next=" + next
121 + ", increment=" + increment
122 + ", paddedNumberLength=" + paddedNumberLength
123 + "]";
124 }
125 }