Bugfix/hashcode fix (#19)

* Fix issue with hash code in the apache preset

* Add tests

.gitignore

@@ -8,4 +8,5 @@ build/
 target/
 *.iml
 *rebel.xml
-src/generated/
+src/generated/
+key.gpg

build.gradle

@@ -15,7 +15,7 @@ apply plugin: 'maven'
 apply from: 'publish.gradle'
 
 group = 'com.jparams'
-version = '1.4.4'
+version = '1.4.5'
 
 sourceCompatibility = 1.8
 

src/main/java/com/jparams/verifier/tostring/HashCodeProvider.java

@@ -0,0 +1,16 @@
+package com.jparams.verifier.tostring;
+
+/**
+ * Hash code provider
+ */
+@FunctionalInterface
+public interface HashCodeProvider
+{
+    /**
+     * Provide object hash code
+     *
+     * @param obj object
+     * @return hash code
+     */
+    int provide(Object obj);
+}

src/main/java/com/jparams/verifier/tostring/ObjectHashCodeProvider.java

@@ -0,0 +1,13 @@
+package com.jparams.verifier.tostring;
+
+/**
+ * Provides the hash code by calling {@link Object#hashCode()}
+ */
+public class ObjectHashCodeProvider implements HashCodeProvider
+{
+    @Override
+    public int provide(final Object obj)
+    {
+        return obj.hashCode();
+    }
+}

src/main/java/com/jparams/verifier/tostring/SystemIdentityHashCodeProvider.java

@@ -0,0 +1,13 @@
+package com.jparams.verifier.tostring;
+
+/**
+ * Provides the System identity hash code by calling {@link System#identityHashCode(Object)}
+ */
+public class SystemIdentityHashCodeProvider implements HashCodeProvider
+{
+    @Override
+    public int provide(final Object obj)
+    {
+        return System.identityHashCode(obj);
+    }
+}

src/main/java/com/jparams/verifier/tostring/ToStringVerifier.java

@@ -56,6 +56,7 @@ public final class ToStringVerifier
     private boolean hashCode = false;
     private String nullValue = "null";
     private boolean failOnExcludedFields = false;
+    private HashCodeProvider hashCodeProvider = new SystemIdentityHashCodeProvider();
 
     private ToStringVerifier(final Collection<Class<?>> classes)
     {
@@ -326,6 +327,19 @@ public ToStringVerifier withNullValue(final String nullValue)
         return this;
     }
 
+    /**
+     * With hash code provider
+     *
+     * @param hashCodeProvider hash code provider
+     * @return verifier
+     */
+    public ToStringVerifier withHashCodeProvider(final HashCodeProvider hashCodeProvider)
+    {
+        assertNotNull(hashCodeProvider);
+        this.hashCodeProvider = hashCodeProvider;
+        return this;
+    }
+
     /**
      * Perform verification
      *
@@ -376,7 +390,7 @@ private Optional<String> verify(final Class<?> clazz)
 
         if (hashCode)
         {
-            verifyHashCode(stringValue, subject.hashCode()).ifPresent(verificationErrors::add);
+            verifyHashCode(stringValue, hashCodeProvider.provide(subject)).ifPresent(verificationErrors::add);
         }
 
         final List<FieldValue> fieldValues = FieldsProvider.provide(clazz, inheritedFields)

src/main/java/com/jparams/verifier/tostring/preset/ApacheToStringBuilderPreset.java

@@ -1,6 +1,7 @@
 package com.jparams.verifier.tostring.preset;
 
 import com.jparams.verifier.tostring.NameStyle;
+import com.jparams.verifier.tostring.SystemIdentityHashCodeProvider;
 import com.jparams.verifier.tostring.ToStringVerifier;
 
 /**
@@ -26,7 +27,7 @@ public void apply(final ToStringVerifier verifier)
                 break;
             case DEFAULT_STYLE:
             case MULTI_LINE_STYLE:
-                verifier.withClassName(NameStyle.NAME).withHashCode(true);
+                verifier.withClassName(NameStyle.NAME).withHashCode(true).withHashCodeProvider(new SystemIdentityHashCodeProvider());
                 break;
             case SHORT_PREFIX_STYLE:
                 verifier.withClassName(NameStyle.SIMPLE_NAME).withHashCode(false);

src/test/java/com/jparams/verifier/tostring/ObjectHashCodeProviderTest.java

@@ -0,0 +1,18 @@
+package com.jparams.verifier.tostring;
+
+import com.jparams.verifier.tostring.pojo.Person;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class ObjectHashCodeProviderTest
+{
+    @Test
+    public void testProvider()
+    {
+        final Person person = new Person(1, "1", "1");
+        final int hashCode = new ObjectHashCodeProvider().provide(person);
+        assertThat(hashCode).isEqualTo(person.hashCode());
+    }
+}

src/test/java/com/jparams/verifier/tostring/SystemIdentityHashCodeProviderTest.java

@@ -0,0 +1,18 @@
+package com.jparams.verifier.tostring;
+
+import com.jparams.verifier.tostring.pojo.Person;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class SystemIdentityHashCodeProviderTest
+{
+    @Test
+    public void testProvider()
+    {
+        final Person person = new Person(1, "1", "1");
+        final int hashCode = new SystemIdentityHashCodeProvider().provide(person);
+        assertThat(hashCode).isEqualTo(System.identityHashCode(person));
+    }
+}

src/test/java/com/jparams/verifier/tostring/ToStringVerifierTest.java

@@ -37,7 +37,7 @@ public void setUp()
         lock.lock(); // to force only one test to run at a time
 
         Person.setStringValue(null);
-        subject = ToStringVerifier.forClass(Person.class);
+        subject = ToStringVerifier.forClass(Person.class).withHashCodeProvider(new ObjectHashCodeProvider());
     }
 
     @After
@@ -369,6 +369,7 @@ public void testToStringWithMultipleClasses()
             ToStringVerifier.forClasses(Person.class, Identified.class)
                             .withMatchingFields((subject, field) -> false)
                             .withHashCode(true)
+                            .withHashCodeProvider(new ObjectHashCodeProvider())
                             .verify();
 
             TestCase.fail("Exception expected");
@@ -391,6 +392,7 @@ public void testToStringWithPackageScan()
             ToStringVerifier.forPackage("com.jparams.verifier.tostring.pojo", false)
                             .withMatchingFields((subject, field) -> false)
                             .withHashCode(true)
+                            .withHashCodeProvider(new ObjectHashCodeProvider())
                             .verify();
 
             TestCase.fail("Exception expected");

src/test/java/com/jparams/verifier/tostring/pojo/Person.java

@@ -3,6 +3,7 @@
 public class Person extends Identified
 {
     private static String stringValue = null;
+    private static Person testInstance = null;
 
     private final String firstName;
     private final String lastName;
@@ -27,6 +28,8 @@ public String getLastName()
     @Override
     public String toString()
     {
+        testInstance = this;
+
         if (stringValue != null)
         {
             return stringValue;
@@ -54,4 +57,9 @@ public static String getStringValue()
     {
         return stringValue;
     }
+
+    public static Person getTestInstance()
+    {
+        return testInstance;
+    }
 }

src/test/java/com/jparams/verifier/tostring/preset/AbstractDataTest.java

@@ -1,13 +1,40 @@
 package com.jparams.verifier.tostring.preset;
 
 import java.math.BigDecimal;
+import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 abstract class AbstractDataTest
 {
     String str;
     List<Integer> list;
     Map<String, BigDecimal> map;
     String[] ary;
+
+    @Override
+    public boolean equals(final Object other)
+    {
+        if (this == other)
+        {
+            return true;
+        }
+
+        if (other == null || getClass() != other.getClass())
+        {
+            return false;
+        }
+
+        final AbstractDataTest that = (AbstractDataTest) other;
+        return Objects.equals(str, that.str) && Objects.equals(list, that.list) && Objects.equals(map, that.map) && Arrays.equals(ary, that.ary);
+    }
+
+    @Override
+    public int hashCode()
+    {
+        int result = Objects.hash(str, list, map);
+        result = 31 * result + Arrays.hashCode(ary);
+        return result;
+    }
 }