| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.commons.lang3.builder; |
| |
| import static org.apache.commons.lang3.reflect.FieldUtils.readField; |
| |
| import java.lang.reflect.Field; |
| import java.lang.reflect.Modifier; |
| |
| import org.apache.commons.lang3.ClassUtils; |
| import org.apache.commons.lang3.reflect.FieldUtils; |
| |
| /** |
| * <p> |
| * Assists in implementing {@link Diffable#diff(Object)} methods. |
| * </p> |
| * <p> |
| * All non-static, non-transient fields (including inherited fields) |
| * of the objects to diff are discovered using reflection and compared |
| * for differences. |
| * </p> |
| * |
| * <p> |
| * To use this class, write code as follows: |
| * </p> |
| * |
| * <pre> |
| * public class Person implements Diffable<Person> { |
| * String name; |
| * int age; |
| * boolean smoker; |
| * ... |
| * |
| * public DiffResult diff(Person obj) { |
| * // No need for null check, as NullPointerException correct if obj is null |
| * return new ReflectionDiffBuilder(this, obj, ToStringStyle.SHORT_PREFIX_STYLE) |
| * .build(); |
| * } |
| * } |
| * </pre> |
| * |
| * <p> |
| * The {@code ToStringStyle} passed to the constructor is embedded in the |
| * returned {@code DiffResult} and influences the style of the |
| * {@code DiffResult.toString()} method. This style choice can be overridden by |
| * calling {@link DiffResult#toString(ToStringStyle)}. |
| * </p> |
| * @param <T> |
| * type of the left and right object to diff. |
| * @see Diffable |
| * @see Diff |
| * @see DiffResult |
| * @see ToStringStyle |
| * @since 3.6 |
| */ |
| public class ReflectionDiffBuilder<T> implements Builder<DiffResult<T>> { |
| |
| private final Object left; |
| private final Object right; |
| private final DiffBuilder<T> diffBuilder; |
| |
| /** |
| * <p> |
| * Constructs a builder for the specified objects with the specified style. |
| * </p> |
| * |
| * <p> |
| * If {@code lhs == rhs} or {@code lhs.equals(rhs)} then the builder will |
| * not evaluate any calls to {@code append(...)} and will return an empty |
| * {@link DiffResult} when {@link #build()} is executed. |
| * </p> |
| * @param lhs |
| * {@code this} object |
| * @param rhs |
| * the object to diff against |
| * @param style |
| * the style will use when outputting the objects, {@code null} |
| * uses the default |
| * @throws IllegalArgumentException |
| * if {@code lhs} or {@code rhs} is {@code null} |
| */ |
| public ReflectionDiffBuilder(final T lhs, final T rhs, final ToStringStyle style) { |
| this.left = lhs; |
| this.right = rhs; |
| diffBuilder = new DiffBuilder<>(lhs, rhs, style); |
| } |
| |
| @Override |
| public DiffResult<T> build() { |
| if (left.equals(right)) { |
| return diffBuilder.build(); |
| } |
| |
| appendFields(left.getClass()); |
| return diffBuilder.build(); |
| } |
| |
| private void appendFields(final Class<?> clazz) { |
| for (final Field field : FieldUtils.getAllFields(clazz)) { |
| if (accept(field)) { |
| try { |
| diffBuilder.append(field.getName(), readField(field, left, true), |
| readField(field, right, true)); |
| } catch (final IllegalAccessException ex) { |
| //this can't happen. Would get a Security exception instead |
| //throw a runtime exception in case the impossible happens. |
| throw new InternalError("Unexpected IllegalAccessException: " + ex.getMessage()); |
| } |
| } |
| } |
| } |
| |
| private boolean accept(final Field field) { |
| if (field.getName().indexOf(ClassUtils.INNER_CLASS_SEPARATOR_CHAR) != -1) { |
| return false; |
| } |
| if (Modifier.isTransient(field.getModifiers())) { |
| return false; |
| } |
| return !Modifier.isStatic(field.getModifiers()); |
| } |
| |
| } |