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.text; 18 19 import static java.util.FormattableFlags.LEFT_JUSTIFY; 20 21 import java.util.Formattable; 22 import java.util.Formatter; 23 24 import org.apache.commons.lang3.StringUtils; 25 26 /** 27 * Provides utilities for working with the {@code Formattable} interface. 28 * 29 * <p>The {@link Formattable} interface provides basic control over formatting 30 * when using a {@code Formatter}. It is primarily concerned with numeric precision 31 * and padding, and is not designed to allow generalised alternate formats.</p> 32 * 33 * @since 1.0 34 */ 35 public class FormattableUtils { 36 37 /** 38 * A format that simply outputs the value as a string. 39 */ 40 private static final String SIMPLEST_FORMAT = "%s"; 41 42 /** 43 * Handles the common {@code Formattable} operations of truncate-pad-append, 44 * with no ellipsis on precision overflow, and padding width underflow with 45 * spaces. 46 * 47 * @param seq the string to handle, not null 48 * @param formatter the destination formatter, not null 49 * @param flags the flags for formatting, see {@code Formattable} 50 * @param width the width of the output, see {@code Formattable} 51 * @param precision the precision of the output, see {@code Formattable} 52 * @return The {@code formatter} instance, not null 53 */ 54 public static Formatter append(final CharSequence seq, final Formatter formatter, final int flags, final int width, 55 final int precision) { 56 return append(seq, formatter, flags, width, precision, ' ', null); 57 } 58 59 /** 60 * Handles the common {@link Formattable} operations of truncate-pad-append, 61 * with no ellipsis on precision overflow. 62 * 63 * @param seq the string to handle, not null 64 * @param formatter the destination formatter, not null 65 * @param flags the flags for formatting, see {@code Formattable} 66 * @param width the width of the output, see {@code Formattable} 67 * @param precision the precision of the output, see {@code Formattable} 68 * @param padChar the pad character to use 69 * @return The {@code formatter} instance, not null 70 */ 71 public static Formatter append(final CharSequence seq, final Formatter formatter, final int flags, final int width, 72 final int precision, final char padChar) { 73 return append(seq, formatter, flags, width, precision, padChar, null); 74 } 75 76 /** 77 * Handles the common {@link Formattable} operations of truncate-pad-append. 78 * 79 * @param seq the string to handle, not null 80 * @param formatter the destination formatter, not null 81 * @param flags the flags for formatting, see {@code Formattable} 82 * @param width the width of the output, see {@code Formattable} 83 * @param precision the precision of the output, see {@code Formattable} 84 * @param padChar the pad character to use 85 * @param truncateEllipsis the ellipsis to use when precision dictates truncation, null or 86 * empty causes a hard truncation 87 * @return The {@code formatter} instance, not null 88 * @throws IllegalArgumentException if {@code ellipsis.length() > precision}, 89 * given that {@code ellipsis} is not null and {@code precision >= 0} 90 */ 91 public static Formatter append(final CharSequence seq, final Formatter formatter, final int flags, final int width, 92 final int precision, final char padChar, final CharSequence truncateEllipsis) { 93 if (!(truncateEllipsis == null || precision < 0 || truncateEllipsis.length() <= precision)) { 94 throw new IllegalArgumentException( 95 String.format("Specified ellipsis '%s' exceeds precision of %s", 96 truncateEllipsis, 97 precision)); 98 } 99 final StringBuilder buf = new StringBuilder(seq); 100 if (precision >= 0 && precision < seq.length()) { 101 final CharSequence ellipsis; 102 if (truncateEllipsis == null) { 103 ellipsis = StringUtils.EMPTY; 104 } else { 105 ellipsis = truncateEllipsis; 106 } 107 buf.replace(precision - ellipsis.length(), seq.length(), ellipsis.toString()); 108 } 109 final boolean leftJustify = (flags & LEFT_JUSTIFY) == LEFT_JUSTIFY; 110 for (int i = buf.length(); i < width; i++) { 111 buf.insert(leftJustify ? i : 0, padChar); 112 } 113 formatter.format(buf.toString()); 114 return formatter; 115 } 116 117 /** 118 * Handles the common {@link Formattable} operations of truncate-pad-append, 119 * padding width underflow with spaces. 120 * 121 * @param seq the string to handle, not null 122 * @param formatter the destination formatter, not null 123 * @param flags the flags for formatting, see {@code Formattable} 124 * @param width the width of the output, see {@code Formattable} 125 * @param precision the precision of the output, see {@code Formattable} 126 * @param ellipsis the ellipsis to use when precision dictates truncation, null or 127 * empty causes a hard truncation 128 * @return The {@code formatter} instance, not null 129 * @throws IllegalArgumentException if {@code ellipsis.length() > precision}, 130 * given that {@code ellipsis} is not null and {@code precision >= 0} 131 */ 132 public static Formatter append(final CharSequence seq, final Formatter formatter, final int flags, final int width, 133 final int precision, final CharSequence ellipsis) { 134 return append(seq, formatter, flags, width, precision, ' ', ellipsis); 135 } 136 137 /** 138 * Gets the default formatted representation of the specified 139 * {@code Formattable}. 140 * 141 * @param formattable the instance to convert to a string, not null 142 * @return The resulting string, not null 143 */ 144 public static String toString(final Formattable formattable) { 145 return String.format(SIMPLEST_FORMAT, formattable); 146 } 147 148 /** 149 * {@code FormattableUtils} instances should NOT be constructed in 150 * standard programming. Instead, the methods of the class should be invoked 151 * statically. 152 * 153 * <p>This constructor is public to permit tools that require a JavaBean 154 * instance to operate.</p> 155 */ 156 public FormattableUtils() { 157 } 158 159 }