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BAEL-2388: moved examples java-collections-maps -> core-java-long. Fixing String comparisons

This commit is contained in:
cror 2018-11-20 13:01:06 +01:00
parent 456f4b0f5a
commit a67c10eec7
12 changed files with 109 additions and 78 deletions
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7
core-java-lang/pom.xml
View File

@ -66,6 +66,12 @@
<artifactId>mail</artifactId>
<version>${javax.mail.version}</version>
</dependency>
<dependency>
<groupId>nl.jqno.equalsverifier</groupId>
<artifactId>equalsverifier</artifactId>
<version>${equalsverifier.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
@ -424,6 +430,7 @@
<maven-shade-plugin.version>3.1.1</maven-shade-plugin.version>
<spring-boot-maven-plugin.version>2.0.3.RELEASE</spring-boot-maven-plugin.version>
<exec-maven-plugin.version>1.6.0</exec-maven-plugin.version>
<equalsverifier.version>3.0.3</equalsverifier.version>
</properties>
</project>

8
java-collections-maps/src/main/java/com/baeldung/map/hashCode/Money.java → core-java-lang/src/main/java/com/baeldung/equalshashcode/Money.java
View File

@ -1,4 +1,4 @@
package com.baeldung.map.hashcode;
package com.baeldung.equalshashcode;
class Money {
@ -17,15 +17,19 @@ class Money {
if (!(o instanceof Money))
return false;
Money other = (Money)o;
boolean currencyCodeEquals = (this.currencyCode == null && other.currencyCode == null)
|| (this.currencyCode != null && this.currencyCode.equals(other.currencyCode));
return this.amount == other.amount
&& this.currencyCode == other.currencyCode;
&& currencyCodeEquals;
}
@Override
public int hashCode() {
int result = 17;
result = 31 * result + amount;
if (currencyCode != null) {
result = 31 * result + currencyCode.hashCode();
}
return result;
}

2
java-collections-maps/src/main/java/com/baeldung/map/hashCode/Team.java → core-java-lang/src/main/java/com/baeldung/equalshashcode/Team.java
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@ -1,4 +1,4 @@
package com.baeldung.map.hashcode;
package com.baeldung.equalshashcode;
class Team {

38
core-java-lang/src/main/java/com/baeldung/equalshashcode/Voucher.java Normal file
View File

@ -0,0 +1,38 @@
package com.baeldung.equalshashcode;
class Voucher {
private Money value;
private String store;
Voucher(int amount, String currencyCode, String store) {
this.value = new Money(amount, currencyCode);
this.store = store;
}
@Override
public boolean equals(Object o) {
if (o == this)
return true;
if (!(o instanceof Voucher))
return false;
Voucher other = (Voucher)o;
boolean valueEquals = (this.value == null && other.value == null)
|| (this.value != null && this.value.equals(other.value));
boolean storeEquals = (this.store == null && other.store == null)
|| (this.store != null && this.store.equals(other.store));
return valueEquals && storeEquals;
}
@Override
public int hashCode() {
int result = 17;
if (this.value != null) {
result = 31 * result + value.hashCode();
}
if (this.store != null) {
result = 31 * result + store.hashCode();
}
return result;
}
}

8
java-collections-maps/src/main/java/com/baeldung/map/hashCode/WrongTeam.java → core-java-lang/src/main/java/com/baeldung/equalshashcode/WrongTeam.java
View File

@ -1,5 +1,11 @@
package com.baeldung.map.hashcode;
package com.baeldung.equalshashcode;
/* (non-Javadoc)
* This class overrides equals, but it doesn't override hashCode.
*
* To see which problems this leads to:
* TeamUnitTest.givenMapKeyWithoutHashCode_whenSearched_thenReturnsWrongValue
*/
class WrongTeam {
String city;

47
core-java-lang/src/main/java/com/baeldung/equalshashcode/WrongVoucher.java Normal file
View File

@ -0,0 +1,47 @@
package com.baeldung.equalshashcode;
/* (non-Javadoc)
* This class extends the Money class that has overridden the equals method and once again overrides the equals method.
*
* To see which problems this leads to:
* MoneyUnitTest.givenMoneyAndVoucherInstances_whenEquals_thenReturnValuesArentSymmetric
*/
class WrongVoucher extends Money {
private String store;
WrongVoucher(int amount, String currencyCode, String store) {
super(amount, currencyCode);
this.store = store;
}
@Override
public boolean equals(Object o) {
if (o == this)
return true;
if (!(o instanceof WrongVoucher))
return false;
WrongVoucher other = (WrongVoucher)o;
boolean currencyCodeEquals = (this.currencyCode == null && other.currencyCode == null)
|| (this.currencyCode != null && this.currencyCode.equals(other.currencyCode));
boolean storeEquals = (this.store == null && other.store == null)
|| (this.store != null && this.store.equals(other.store));
return this.amount == other.amount
&& currencyCodeEquals
&& storeEquals;
}
@Override
public int hashCode() {
int result = 17;
result = 31 * result + amount;
if (this.currencyCode != null) {
result = 31 * result + currencyCode.hashCode();
}
if (this.store != null) {
result = 31 * result + store.hashCode();
}
return result;
}
}

2
java-collections-maps/src/test/java/com/baeldung/map/hashCode/MoneyUnitTest.java → core-java-lang/src/test/java/com/baeldung/equalshashcode/MoneyUnitTest.java
View File

@ -1,4 +1,4 @@
package com.baeldung.map.hashcode;
package com.baeldung.equalshashcode;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.assertFalse;

2
java-collections-maps/src/test/java/com/baeldung/map/hashCode/TeamUnitTest.java → core-java-lang/src/test/java/com/baeldung/equalshashcode/TeamUnitTest.java
View File

@ -1,4 +1,4 @@
package com.baeldung.map.hashcode;
package com.baeldung.equalshashcode;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;

6
java-collections-maps/pom.xml
View File

@ -41,12 +41,6 @@
<artifactId>streamex</artifactId>
<version>0.6.5</version>
</dependency>
<dependency>
<groupId>nl.jqno.equalsverifier</groupId>
<artifactId>equalsverifier</artifactId>
<version>3.0.3</version>
<scope>test</scope>
</dependency>
</dependencies>
<properties>

31
java-collections-maps/src/main/java/com/baeldung/map/hashCode/Voucher.java
View File

@ -1,31 +0,0 @@
package com.baeldung.map.hashcode;
class Voucher {
private Money value;
private String store;
Voucher(int amount, String currencyCode, String store) {
this.value = new Money(amount, currencyCode);
this.store = store;
}
@Override
public boolean equals(Object o) {
if (o == this)
return true;
if (!(o instanceof Voucher))
return false;
Voucher other = (Voucher)o;
return this.value == other.value
&& this.store == other.store;
}
@Override
public int hashCode() {
int result = 17;
result = 31 * result + value.hashCode();
result = 31 * result + store.hashCode();
return result;
}
}

33
java-collections-maps/src/main/java/com/baeldung/map/hashCode/WrongVoucher.java
View File

@ -1,33 +0,0 @@
package com.baeldung.map.hashcode;
class WrongVoucher extends Money {
private String store;
WrongVoucher(int amount, String currencyCode, String store) {
super(amount, currencyCode);
this.store = store;
}
@Override
public boolean equals(Object o) {
if (o == this)
return true;
if (!(o instanceof WrongVoucher))
return false;
WrongVoucher other = (WrongVoucher)o;
return this.amount == other.amount
&& this.currencyCode == other.currencyCode
&& this.store == other.store;
}
@Override
public int hashCode() {
int result = 17;
result = 31 * result + amount;
result = 31 * result + currencyCode.hashCode();
result = 31 * result + store.hashCode();
return result;
}
}

1
java-collections-maps/src/main/java/com/baeldung/map/hashCode/equalsverifier_notes.txt
View File

@ -1 +0,0 @@
Non-nullity: hashCode throws NullPointerException on field city.