org.apache.commons.lang3.builder.DiffResult Maven / Gradle / Ivy
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/**
* 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 java.util.Collections;
import java.util.Iterator;
import java.util.List;
import org.apache.commons.lang3.Validate;
/**
*
* A {@code DiffResult} contains a collection of the differences between two
* {@link Diffable} objects. Typically these differences are displayed using
* {@link #toString()} method, which returns a string describing the fields that
* differ between the objects.
*
*
* Use a {@link DiffBuilder} to build a {@code DiffResult} comparing two objects.
*
*
* @since 3.3
*/
public class DiffResult implements Iterable> {
/**
*
* The {@code String} returned when the objects have no differences:
* {@value}
*
*/
public static final String OBJECTS_SAME_STRING = "";
private static final String DIFFERS_STRING = "differs from";
private final List> diffs;
private final Object lhs;
private final Object rhs;
private final ToStringStyle style;
/**
*
* Creates a {@link DiffResult} containing the differences between two
* objects.
*
*
* @param lhs
* the left hand object
* @param rhs
* the right hand object
* @param diffs
* the list of differences, may be empty
* @param style
* the style to use for the {@link #toString()} method. May be
* {@code null}, in which case
* {@link ToStringStyle#DEFAULT_STYLE} is used
* @throws IllegalArgumentException
* if {@code lhs}, {@code rhs} or {@code diffs} is {@code null}
*/
DiffResult(final Object lhs, final Object rhs, final List> diffs,
final ToStringStyle style) {
Validate.isTrue(lhs != null, "Left hand object cannot be null");
Validate.isTrue(rhs != null, "Right hand object cannot be null");
Validate.isTrue(diffs != null, "List of differences cannot be null");
this.diffs = diffs;
this.lhs = lhs;
this.rhs = rhs;
if (style == null) {
this.style = ToStringStyle.DEFAULT_STYLE;
} else {
this.style = style;
}
}
/**
*
* Returns an unmodifiable list of {@code Diff}s. The list may be empty if
* there were no differences between the objects.
*
*
* @return an unmodifiable list of {@code Diff}s
*/
public List> getDiffs() {
return Collections.unmodifiableList(diffs);
}
/**
*
* Returns the number of differences between the two objects.
*
*
* @return the number of differences
*/
public int getNumberOfDiffs() {
return diffs.size();
}
/**
*
* Returns the style used by the {@link #toString()} method.
*
*
* @return the style
*/
public ToStringStyle getToStringStyle() {
return style;
}
/**
*
* Builds a {@code String} description of the differences contained within
* this {@code DiffResult}. A {@link ToStringBuilder} is used for each object
* and the style of the output is governed by the {@code ToStringStyle}
* passed to the constructor.
*
*
*
* If there are no differences stored in this list, the method will return
* {@link #OBJECTS_SAME_STRING}. Otherwise, using the example given in
* {@link Diffable} and {@link ToStringStyle#SHORT_PREFIX_STYLE}, an output
* might be:
*
*
*
* Person[name=John Doe,age=32] differs from Person[name=Joe Bloggs,age=26]
*
*
*
* This indicates that the objects differ in name and age, but not in
* smoking status.
*
*
*
* To use a different {@code ToStringStyle} for an instance of this class,
* use {@link #toString(ToStringStyle)}.
*
*
* @return a {@code String} description of the differences.
*/
@Override
public String toString() {
return toString(style);
}
/**
*
* Builds a {@code String} description of the differences contained within
* this {@code DiffResult}, using the supplied {@code ToStringStyle}.
*
*
* @param style
* the {@code ToStringStyle} to use when outputting the objects
*
* @return a {@code String} description of the differences.
*/
public String toString(final ToStringStyle style) {
if (diffs.isEmpty()) {
return OBJECTS_SAME_STRING;
}
final ToStringBuilder lhsBuilder = new ToStringBuilder(lhs, style);
final ToStringBuilder rhsBuilder = new ToStringBuilder(rhs, style);
for (final Diff diff : diffs) {
lhsBuilder.append(diff.getFieldName(), diff.getLeft());
rhsBuilder.append(diff.getFieldName(), diff.getRight());
}
return String.format("%s %s %s", lhsBuilder.build(), DIFFERS_STRING,
rhsBuilder.build());
}
/**
*
* Returns an iterator over the {@code Diff} objects contained in this list.
*
*
* @return the iterator
*/
@Override
public Iterator> iterator() {
return diffs.iterator();
}
}