001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.lang3.builder; 018 019import java.lang.reflect.Field; 020import java.lang.reflect.Modifier; 021import java.util.Arrays; 022 023import org.apache.commons.lang3.ArraySorter; 024import org.apache.commons.lang3.ArrayUtils; 025import org.apache.commons.lang3.ClassUtils; 026import org.apache.commons.lang3.reflect.FieldUtils; 027 028/** 029 * Assists in implementing {@link Diffable#diff(Object)} methods. 030 * 031 * <p> 032 * All non-static, non-transient fields (including inherited fields) of the objects to diff are discovered using reflection and compared for differences. 033 * </p> 034 * 035 * <p> 036 * To use this class, write code as follows: 037 * </p> 038 * 039 * <pre>{@code 040 * public class Person implements Diffable<Person> { 041 * String name; 042 * int age; 043 * boolean smoker; 044 * ... 045 * 046 * public DiffResult diff(Person obj) { 047 * // No need for null check, as NullPointerException correct if obj is null 048 * return new ReflectionDiffBuilder.<Person>builder() 049 * .setDiffBuilder(DiffBuilder.<Person>builder() 050 * .setLeft(this) 051 * .setRight(obj) 052 * .setStyle(ToStringStyle.SHORT_PREFIX_STYLE) 053 * .build()) 054 * .setExcludeFieldNames("userName", "password") 055 * .build(); 056 * } 057 * } 058 * }</pre> 059 * 060 * <p> 061 * The {@link ToStringStyle} passed to the constructor is embedded in the returned {@link DiffResult} and influences the style of the 062 * {@code DiffResult.toString()} method. This style choice can be overridden by calling {@link DiffResult#toString(ToStringStyle)}. 063 * </p> 064 * <p> 065 * See {@link DiffBuilder} for a non-reflection based version of this class. 066 * </p> 067 * 068 * @param <T> type of the left and right object to diff. 069 * @see Diffable 070 * @see Diff 071 * @see DiffResult 072 * @see ToStringStyle 073 * @see DiffBuilder 074 * @since 3.6 075 */ 076public class ReflectionDiffBuilder<T> implements Builder<DiffResult<T>> { 077 078 /** 079 * Constructs a new instance. 080 * 081 * @param <T> type of the left and right object. 082 * @since 3.15.0 083 */ 084 public static final class Builder<T> { 085 086 private String[] excludeFieldNames = ArrayUtils.EMPTY_STRING_ARRAY; 087 private DiffBuilder<T> diffBuilder; 088 089 /** 090 * Builds a new configured {@link ReflectionDiffBuilder}. 091 * 092 * @return a new configured {@link ReflectionDiffBuilder}. 093 */ 094 public ReflectionDiffBuilder<T> build() { 095 return new ReflectionDiffBuilder<>(diffBuilder, excludeFieldNames); 096 } 097 098 /** 099 * Sets the DiffBuilder. 100 * 101 * @param diffBuilder the DiffBuilder. 102 * @return {@code this} instance. 103 */ 104 public Builder<T> setDiffBuilder(final DiffBuilder<T> diffBuilder) { 105 this.diffBuilder = diffBuilder; 106 return this; 107 } 108 109 /** 110 * Sets field names to exclude from output. Intended for fields like {@code "password"} or {@code "lastModificationDate"}. 111 * 112 * @param excludeFieldNames field names to exclude. 113 * @return {@code this} instance. 114 */ 115 public Builder<T> setExcludeFieldNames(final String... excludeFieldNames) { 116 this.excludeFieldNames = toExcludeFieldNames(excludeFieldNames); 117 return this; 118 } 119 120 } 121 122 /** 123 * Constructs a new {@link Builder}. 124 * 125 * @param <T> type of the left and right object. 126 * @return a new {@link Builder}. 127 * @since 3.15.0 128 */ 129 public static <T> Builder<T> builder() { 130 return new Builder<>(); 131 } 132 133 private static String[] toExcludeFieldNames(final String[] excludeFieldNames) { 134 if (excludeFieldNames == null) { 135 return ArrayUtils.EMPTY_STRING_ARRAY; 136 } 137 // clone and remove nulls 138 return ArraySorter.sort(ReflectionToStringBuilder.toNoNullStringArray(excludeFieldNames)); 139 } 140 141 private final DiffBuilder<T> diffBuilder; 142 143 /** 144 * Field names to exclude from output. Intended for fields like {@code "password"} or {@code "lastModificationDate"}. 145 */ 146 private String[] excludeFieldNames; 147 148 private ReflectionDiffBuilder(final DiffBuilder<T> diffBuilder, final String[] excludeFieldNames) { 149 this.diffBuilder = diffBuilder; 150 this.excludeFieldNames = excludeFieldNames; 151 } 152 153 /** 154 * Constructs a builder for the specified objects with the specified style. 155 * 156 * <p> 157 * If {@code left == right} or {@code left.equals(right)} then the builder will not evaluate any calls to {@code append(...)} and will return an empty 158 * {@link DiffResult} when {@link #build()} is executed. 159 * </p> 160 * 161 * @param left {@code this} object. 162 * @param right the object to diff against. 163 * @param style the style will use when outputting the objects, {@code null} uses the default 164 * @throws IllegalArgumentException if {@code left} or {@code right} is {@code null}. 165 * @deprecated Use {@link Builder}. 166 */ 167 @Deprecated 168 public ReflectionDiffBuilder(final T left, final T right, final ToStringStyle style) { 169 this(DiffBuilder.<T>builder().setLeft(left).setRight(right).setStyle(style).build(), null); 170 } 171 172 private boolean accept(final Field field) { 173 if (field.getName().indexOf(ClassUtils.INNER_CLASS_SEPARATOR_CHAR) != -1) { 174 return false; 175 } 176 if (Modifier.isTransient(field.getModifiers())) { 177 return false; 178 } 179 if (Modifier.isStatic(field.getModifiers())) { 180 return false; 181 } 182 if (this.excludeFieldNames != null && Arrays.binarySearch(this.excludeFieldNames, field.getName()) >= 0) { 183 // Reject fields from the getExcludeFieldNames list. 184 return false; 185 } 186 return !field.isAnnotationPresent(DiffExclude.class); 187 } 188 189 private void appendFields(final Class<?> clazz) { 190 for (final Field field : FieldUtils.getAllFields(clazz)) { 191 if (accept(field)) { 192 try { 193 diffBuilder.append(field.getName(), readField(field, getLeft()), readField(field, getRight())); 194 } catch (final IllegalAccessException e) { 195 // this can't happen. Would get a Security exception instead 196 // throw a runtime exception in case the impossible happens. 197 throw new IllegalArgumentException("Unexpected IllegalAccessException: " + e.getMessage(), e); 198 } 199 } 200 } 201 } 202 203 @Override 204 public DiffResult<T> build() { 205 if (getLeft().equals(getRight())) { 206 return diffBuilder.build(); 207 } 208 209 appendFields(getLeft().getClass()); 210 return diffBuilder.build(); 211 } 212 213 /** 214 * Gets the field names that should be excluded from the diff. 215 * 216 * @return Returns the excludeFieldNames. 217 * @since 3.13.0 218 */ 219 public String[] getExcludeFieldNames() { 220 return this.excludeFieldNames.clone(); 221 } 222 223 private T getLeft() { 224 return diffBuilder.getLeft(); 225 } 226 227 private T getRight() { 228 return diffBuilder.getRight(); 229 } 230 231 private Object readField(final Field field, final Object target) throws IllegalAccessException { 232 return FieldUtils.readField(field, target, true); 233 } 234 235 /** 236 * Sets the field names to exclude. 237 * 238 * @param excludeFieldNames The field names to exclude from the diff or {@code null}. 239 * @return {@code this} 240 * @since 3.13.0 241 * @deprecated Use {@link Builder#setExcludeFieldNames(String[])}. 242 */ 243 @Deprecated 244 public ReflectionDiffBuilder<T> setExcludeFieldNames(final String... excludeFieldNames) { 245 this.excludeFieldNames = toExcludeFieldNames(excludeFieldNames); 246 return this; 247 } 248 249}