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(Issue SQiShER#52) Added some more tests and refactored API
1 parent e7dbf94 commit 6b2fa25

8 files changed

Lines changed: 161 additions & 90 deletions

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‎src/main/java/de/danielbechler/diff/CircularReferenceDetector.java‎

Lines changed: 20 additions & 20 deletions
Original file line numberDiff line numberDiff line change
@@ -17,6 +17,7 @@
1717
package de.danielbechler.diff;
1818

1919
import de.danielbechler.diff.path.*;
20+
import de.danielbechler.util.*;
2021

2122
import java.util.*;
2223

@@ -25,8 +26,7 @@ class CircularReferenceDetector
2526
{
2627
private final Deque<Entry> stack = new LinkedList<Entry>();
2728

28-
private boolean isNew = true;
29-
private boolean treatEqualObjectsAsIdentical;
29+
private ReferenceMatchingMode referenceMatchingMode = ReferenceMatchingMode.EQUALITY_OPERATOR;
3030

3131
private static class Entry
3232
{
@@ -54,28 +54,12 @@ public CircularReferenceDetector()
5454
{
5555
}
5656

57-
/** @deprecated Only used in tests. */
58-
@Deprecated
59-
public boolean isNew()
60-
{
61-
return isNew;
62-
}
63-
64-
public void setTreatEqualObjectsAsIdentical(final boolean treatEqualObjectsAsIdentical)
65-
{
66-
this.treatEqualObjectsAsIdentical = treatEqualObjectsAsIdentical;
67-
}
68-
6957
public void push(final Object instance, final PropertyPath propertyPath)
7058
{
7159
if (instance == null)
7260
{
7361
return;
7462
}
75-
if (isNew)
76-
{
77-
isNew = false;
78-
}
7963
if (knows(instance))
8064
{
8165
throw new CircularReferenceException(entryForInstance(instance).getPropertyPath());
@@ -99,14 +83,15 @@ public boolean knows(final Object needle)
9983

10084
protected boolean isMatch(final Object anObject, final Object anotherObject)
10185
{
102-
if (treatEqualObjectsAsIdentical)
86+
if (referenceMatchingMode == ReferenceMatchingMode.EQUALS_METHOD)
10387
{
10488
return anotherObject != null && anObject != null && anotherObject.equals(anObject);
10589
}
106-
else
90+
else if (referenceMatchingMode == ReferenceMatchingMode.EQUALITY_OPERATOR)
10791
{
10892
return anotherObject == anObject;
10993
}
94+
throw new IllegalStateException("Missing reference matching mode");
11095
}
11196

11297
private Entry entryForInstance(final Object instance)
@@ -142,6 +127,12 @@ public int size()
142127
return stack.size();
143128
}
144129

130+
public void setReferenceMatchingMode(final ReferenceMatchingMode referenceMatchingMode)
131+
{
132+
Assert.notNull(referenceMatchingMode, "referenceMatchingMode");
133+
this.referenceMatchingMode = referenceMatchingMode;
134+
}
135+
145136
public static class CircularReferenceException extends RuntimeException
146137
{
147138
private static final long serialVersionUID = 1L;
@@ -165,4 +156,13 @@ public Throwable fillInStackTrace()
165156
return null;
166157
}
167158
}
159+
160+
public static enum ReferenceMatchingMode
161+
{
162+
/** Compares objects using the <code>==</code> operator. */
163+
EQUALITY_OPERATOR,
164+
165+
/** Compares objects using {@linkplain Object#equals(Object)}. */
166+
EQUALS_METHOD
167+
}
168168
}

‎src/main/java/de/danielbechler/diff/Configuration.java‎

Lines changed: 25 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -29,6 +29,23 @@
2929
@SuppressWarnings("UnusedDeclaration")
3030
public class Configuration implements NodeInspector
3131
{
32+
/**
33+
* Defines how the {@link CircularReferenceDetector} compares object instances. The default is {@link
34+
* de.danielbechler.diff.Configuration.CircularReferenceMatchingMode#EQUALITY_OPERATOR} and this should be
35+
* sufficient in mose cases. However, you may be dealing with an object model that returns copies of its
36+
* properties, instead of reusing the exact same instance. In this cases it would be easy to end up in
37+
* infinite loops, as the default circular reference detection would not be able to detect this. In those
38+
* cases you should switch to the {@link #EQUALS_METHOD} mode. The trade-off is, that this renders you unable
39+
* to nest equal but different objects.
40+
*/
41+
public enum CircularReferenceMatchingMode
42+
{
43+
/** Compares objects using the <code>==</code> operator. */
44+
EQUALITY_OPERATOR,
45+
46+
/** Compares objects using {@linkplain Object#equals(Object)}. */
47+
EQUALS_METHOD
48+
}
3249

3350
/**
3451
* Defines how default values of primitive types (int, long, short, byte, char, boolean, float, double) will
@@ -66,7 +83,7 @@ public enum PrimitiveDefaultValueMode
6683
private boolean returnCircularNodes = true;
6784
private boolean returnChildrenOfAddedNodes = false;
6885
private boolean returnChildrenOfRemovedNodes = false;
69-
private boolean treatEqualObjectsAsIdentical = false;
86+
private CircularReferenceMatchingMode circularReferenceMatchingMode = CircularReferenceMatchingMode.EQUALITY_OPERATOR;
7087
private PrimitiveDefaultValueMode treatPrimitivesAs = PrimitiveDefaultValueMode.UNASSIGNED;
7188

7289
public Configuration withCategory(final String category)
@@ -185,28 +202,20 @@ public Configuration treatPrimitiveDefaultValuesAs(final PrimitiveDefaultValueMo
185202
return this;
186203
}
187204

188-
/**
189-
* If this setting is set to true, the circular reference detector will treat equal objects as identical
190-
* (<code>==</code>). Otherwise only exact same instances will be considered identical. This is very useful
191-
* if you are dealing with objects that return copies of their properties, which could easily lead to
192-
* infinite loops unless equality is taken into account.
193-
*
194-
* @return This instance for easy chaining.
195-
*/
196-
public Configuration treatEqualObjectsAsIdentical(final boolean value)
205+
public PrimitiveDefaultValueMode getPrimitiveDefaultValueMode()
197206
{
198-
this.treatEqualObjectsAsIdentical = value;
199-
return this;
207+
return treatPrimitivesAs;
200208
}
201209

202-
public boolean shouldTreatEqualObjectsAsSame()
210+
public CircularReferenceMatchingMode getCircularReferenceMatchingMode()
203211
{
204-
return treatEqualObjectsAsIdentical;
212+
return circularReferenceMatchingMode;
205213
}
206214

207-
public PrimitiveDefaultValueMode getPrimitiveDefaultValueMode()
215+
public void matchCircularReferencesUsing(final CircularReferenceMatchingMode circularReferenceMatchingMode)
208216
{
209-
return treatPrimitivesAs;
217+
Assert.notNull(circularReferenceMatchingMode, "circularReferenceMatchingMode");
218+
this.circularReferenceMatchingMode = circularReferenceMatchingMode;
210219
}
211220

212221
public boolean isIgnored(final Node node)

‎src/main/java/de/danielbechler/diff/DifferDelegator.java‎

Lines changed: 8 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -28,11 +28,11 @@
2828
class DifferDelegator
2929
{
3030
private static final Logger logger = LoggerFactory.getLogger(DifferDelegator.class);
31-
private static final ThreadLocal<CircularReferenceDetector> WORKING_CIRCULAR_REFERENCE_DETECTOR_THREAD_LOCAL = new ThreadLocal<CircularReferenceDetector>();
32-
private static final ThreadLocal<CircularReferenceDetector> BASE_CIRCULAR_REFERENCE_DETECTOR_THREAD_LOCAL = new ThreadLocal<CircularReferenceDetector>();
3331

3432
private final DifferFactory differFactory;
3533
private final CircularReferenceDetectorFactory circularReferenceDetectorFactory;
34+
private CircularReferenceDetector workingCircularReferenceDetector;
35+
private CircularReferenceDetector baseCircularReferenceDetector;
3636

3737
public DifferDelegator(final DifferFactory differFactory,
3838
final CircularReferenceDetectorFactory circularReferenceDetectorFactory)
@@ -136,20 +136,20 @@ private Node compare(final Node parentNode, final Instances instances)
136136

137137
protected final void resetInstanceMemory()
138138
{
139-
WORKING_CIRCULAR_REFERENCE_DETECTOR_THREAD_LOCAL.set(circularReferenceDetectorFactory.create());
140-
BASE_CIRCULAR_REFERENCE_DETECTOR_THREAD_LOCAL.set(circularReferenceDetectorFactory.create());
139+
workingCircularReferenceDetector = circularReferenceDetectorFactory.create();
140+
baseCircularReferenceDetector = circularReferenceDetectorFactory.create();
141141
}
142142

143143
protected void forgetInstances(final Instances instances)
144144
{
145-
WORKING_CIRCULAR_REFERENCE_DETECTOR_THREAD_LOCAL.get().remove(instances.getWorking());
146-
BASE_CIRCULAR_REFERENCE_DETECTOR_THREAD_LOCAL.get().remove(instances.getBase());
145+
workingCircularReferenceDetector.remove(instances.getWorking());
146+
baseCircularReferenceDetector.remove(instances.getBase());
147147
}
148148

149149
protected void rememberInstances(final Node parentNode, final Instances instances)
150150
{
151151
final PropertyPath propertyPath = instances.getPropertyPath(parentNode);
152-
WORKING_CIRCULAR_REFERENCE_DETECTOR_THREAD_LOCAL.get().push(instances.getWorking(), propertyPath);
153-
BASE_CIRCULAR_REFERENCE_DETECTOR_THREAD_LOCAL.get().push(instances.getBase(), propertyPath);
152+
workingCircularReferenceDetector.push(instances.getWorking(), propertyPath);
153+
baseCircularReferenceDetector.push(instances.getBase(), propertyPath);
154154
}
155155
}

‎src/main/java/de/danielbechler/diff/ObjectDiffer.java‎

Lines changed: 25 additions & 18 deletions
Original file line numberDiff line numberDiff line change
@@ -18,6 +18,8 @@
1818

1919
import de.danielbechler.diff.node.*;
2020

21+
import static de.danielbechler.diff.Configuration.CircularReferenceMatchingMode.*;
22+
2123
/**
2224
* This is the entry point for all comparisons. It determines the type of the given objects and passes them to
2325
* the appropriate {@link Differ}.
@@ -26,6 +28,24 @@
2628
*/
2729
public class ObjectDiffer
2830
{
31+
private static final CircularReferenceDetectorFactory CIRCULAR_REFERENCE_DETECTOR_WITH_EQUALITY_OPERATOR_FACTORY = new CircularReferenceDetectorFactory()
32+
{
33+
public CircularReferenceDetector create()
34+
{
35+
final CircularReferenceDetector circularReferenceDetector = new CircularReferenceDetector();
36+
circularReferenceDetector.setReferenceMatchingMode(CircularReferenceDetector.ReferenceMatchingMode.EQUALITY_OPERATOR);
37+
return circularReferenceDetector;
38+
}
39+
};
40+
private static final CircularReferenceDetectorFactory CIRCULAR_REFERENCE_DETECTOR_WITH_EQUALS_METHOD_FACTORY = new CircularReferenceDetectorFactory()
41+
{
42+
public CircularReferenceDetector create()
43+
{
44+
final CircularReferenceDetector circularReferenceDetector = new CircularReferenceDetector();
45+
circularReferenceDetector.setReferenceMatchingMode(CircularReferenceDetector.ReferenceMatchingMode.EQUALS_METHOD);
46+
return circularReferenceDetector;
47+
}
48+
};
2949
private final Configuration configuration;
3050
private final DifferDelegator delegator;
3151

@@ -63,27 +83,14 @@ public Configuration getConfiguration()
6383

6484
private static CircularReferenceDetectorFactory newCircularReferenceDetectorFactory(final Configuration configuration)
6585
{
66-
if (configuration.shouldTreatEqualObjectsAsSame())
86+
if (configuration.getCircularReferenceMatchingMode() == EQUALS_METHOD)
6787
{
68-
return new CircularReferenceDetectorFactory()
69-
{
70-
public CircularReferenceDetector create()
71-
{
72-
final CircularReferenceDetector circularReferenceDetector = new CircularReferenceDetector();
73-
circularReferenceDetector.setTreatEqualObjectsAsIdentical(true);
74-
return circularReferenceDetector;
75-
}
76-
};
88+
return CIRCULAR_REFERENCE_DETECTOR_WITH_EQUALS_METHOD_FACTORY;
7789
}
78-
else
90+
else if (configuration.getCircularReferenceMatchingMode() == EQUALITY_OPERATOR)
7991
{
80-
return new CircularReferenceDetectorFactory()
81-
{
82-
public CircularReferenceDetector create()
83-
{
84-
return new CircularReferenceDetector();
85-
}
86-
};
92+
return CIRCULAR_REFERENCE_DETECTOR_WITH_EQUALITY_OPERATOR_FACTORY;
8793
}
94+
throw new IllegalStateException();
8895
}
8996
}

‎src/test/java/de/danielbechler/diff/CircularReferenceDetectorTest.java‎

Lines changed: 44 additions & 27 deletions
Original file line numberDiff line numberDiff line change
@@ -16,10 +16,13 @@
1616

1717
package de.danielbechler.diff;
1818

19+
import de.danielbechler.diff.mock.*;
1920
import de.danielbechler.diff.path.*;
21+
import org.fest.assertions.api.*;
2022
import org.testng.annotations.*;
2123

22-
import static org.hamcrest.MatcherAssert.*;
24+
import static org.fest.assertions.api.Assertions.assertThat;
25+
import static org.hamcrest.MatcherAssert.assertThat;
2326
import static org.hamcrest.core.Is.*;
2427
import static org.testng.Assert.*;
2528

@@ -32,27 +35,7 @@ public class CircularReferenceDetectorTest
3235
public void setUp()
3336
{
3437
circularReferenceDetector = new CircularReferenceDetector();
35-
}
36-
37-
@Test
38-
public void testIsNew_returns_true_if_nothing_has_been_pushed() throws Exception
39-
{
40-
assertTrue(circularReferenceDetector.isNew());
41-
}
42-
43-
@Test
44-
public void testIsNew_returns_false_if_instance_has_been_pushed() throws Exception
45-
{
46-
circularReferenceDetector.push("foo", PropertyPath.buildRootPath());
47-
assertFalse(circularReferenceDetector.isNew());
48-
}
49-
50-
@Test
51-
public void testIsNew_returns_false_if_instance_has_been_pushed_but_later_removed() throws Exception
52-
{
53-
circularReferenceDetector.push("foo", PropertyPath.buildRootPath());
54-
circularReferenceDetector.remove("foo");
55-
assertFalse(circularReferenceDetector.isNew());
38+
circularReferenceDetector.setReferenceMatchingMode(CircularReferenceDetector.ReferenceMatchingMode.EQUALITY_OPERATOR);
5639
}
5740

5841
@Test
@@ -69,14 +52,23 @@ public void testPush_adds_unknown_object_to_stack() throws Exception
6952
assertThat(circularReferenceDetector.size(), is(1));
7053
}
7154

72-
@Test(expectedExceptions = CircularReferenceDetector.CircularReferenceException.class)
55+
@Test
7356
public void testPush_throws_CircularReferenceException_on_known_object() throws Exception
7457
{
7558
circularReferenceDetector.push("foo", PropertyPath.buildRootPath());
76-
circularReferenceDetector.push("foo", PropertyPath.createBuilder()
77-
.withRoot()
78-
.withPropertyName("test")
79-
.build());
59+
try
60+
{
61+
circularReferenceDetector.push("foo", PropertyPath.createBuilder()
62+
.withRoot()
63+
.withPropertyName("test")
64+
.build());
65+
Assertions.fail("Expected CircularReferenceException wasn't thrown.");
66+
}
67+
catch (CircularReferenceDetector.CircularReferenceException e)
68+
{
69+
final PropertyPath propertyPath = e.getPropertyPath();
70+
assertThat(propertyPath).isEqualTo(PropertyPath.buildRootPath());
71+
}
8072
}
8173

8274
@Test
@@ -123,4 +115,29 @@ public void testKnows_returns_false_if_instance_has_been_pushed_but_later_remove
123115
circularReferenceDetector.remove("foo");
124116
assertFalse(circularReferenceDetector.knows("foo"));
125117
}
118+
119+
@Test
120+
public void knowsEqualObject_whenReferenceMatchingModeIsSetToEqualsMethod()
121+
{
122+
circularReferenceDetector.setReferenceMatchingMode(CircularReferenceDetector.ReferenceMatchingMode.EQUALS_METHOD);
123+
circularReferenceDetector.push(new ObjectWithString("foo"), PropertyPath.buildRootPath());
124+
assertThat(circularReferenceDetector.knows(new ObjectWithString("foo"))).isTrue();
125+
}
126+
127+
@Test
128+
public void removesEqualObject_whenReferenceMatchingModeIsSetToEqualsMethod()
129+
{
130+
circularReferenceDetector.setReferenceMatchingMode(CircularReferenceDetector.ReferenceMatchingMode.EQUALS_METHOD);
131+
circularReferenceDetector.push(new ObjectWithString("foo"), PropertyPath.buildRootPath());
132+
circularReferenceDetector.remove(new ObjectWithString("foo"));
133+
assertThat(circularReferenceDetector.size()).isEqualTo(0);
134+
}
135+
136+
@Test(expectedExceptions = CircularReferenceDetector.CircularReferenceException.class)
137+
public void throwsException_onAttemptToPushEqualObject_whenReferenceMatchingModeIsSetToEqualsMethod()
138+
{
139+
circularReferenceDetector.setReferenceMatchingMode(CircularReferenceDetector.ReferenceMatchingMode.EQUALS_METHOD);
140+
circularReferenceDetector.push(new ObjectWithString("foo"), PropertyPath.buildRootPath());
141+
circularReferenceDetector.push(new ObjectWithString("foo"), PropertyPath.buildRootPath());
142+
}
126143
}

‎src/test/java/de/danielbechler/diff/integration/graph/CircularReferenceDetectionBasedOnEqualsTest.java‎

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -22,6 +22,8 @@
2222
import de.danielbechler.diff.node.*;
2323
import org.testng.annotations.*;
2424

25+
import static de.danielbechler.diff.Configuration.CircularReferenceMatchingMode.*;
26+
2527
/** @author Daniel Bechler */
2628
public class CircularReferenceDetectionBasedOnEqualsTest
2729
{
@@ -32,7 +34,7 @@ public void setUp() throws Exception
3234
{
3335
final Configuration configuration = new Configuration();
3436
configuration.withChildrenOfAddedNodes();
35-
configuration.treatEqualObjectsAsIdentical(true);
37+
configuration.matchCircularReferencesUsing(EQUALS_METHOD);
3638
objectDiffer = ObjectDifferFactory.getInstance(configuration);
3739
}
3840

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