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Refactor Reflection examples

This commit is contained in:
Grzegorz Piwowarek 2016-09-04 08:18:17 +02:00
parent 89944e9a9f
commit 6bd09ce0ae
8 changed files with 342 additions and 330 deletions
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4
reflection/pom.xml
View File

@ -12,8 +12,8 @@
<artifactId>maven-compiler-plugin</artifactId>
<version>3.3</version>
<configuration>
<source>7</source>
<target>7</target>
<source>8</source>
<target>8</target>
</configuration>
</plugin>
</plugins>

4
reflection/src/main/java/com/baeldung/reflection/Animal.java
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@ -1,7 +1,9 @@
package com.baeldung.reflection;
public abstract class Animal implements Eating{
public abstract class Animal implements Eating {
public static final String CATEGORY = "domestic";
private String name;
public Animal(String name) {

3
reflection/src/main/java/com/baeldung/reflection/Bird.java
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@ -2,13 +2,16 @@ package com.baeldung.reflection;
public class Bird extends Animal {
private boolean walks;
public Bird() {
super("bird");
}
public Bird(String name, boolean walks) {
super(name);
setWalks(walks);
}
public Bird(String name) {
super(name);
}

2
reflection/src/main/java/com/baeldung/reflection/Goat.java
View File

@ -1,6 +1,6 @@
package com.baeldung.reflection;
public class Goat extends Animal implements Locomotion{
public class Goat extends Animal implements Locomotion {
public Goat(String name) {
super(name);

123
reflection/src/test/java/com/baeldung/reflection/ReflectionTest.java
View File

@ -1,27 +1,26 @@
package com.baeldung.reflection;
import static org.junit.Assert.*;
import java.lang.reflect.*;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.junit.Test;
import java.lang.reflect.*;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Stream;
import static java.util.stream.Collectors.toList;
import static org.junit.Assert.*;
public class ReflectionTest {
@Test
public void givenObject_whenGetsFieldNamesAtRuntime_thenCorrect() {
Object person = new Person();
Field[] fields = person.getClass().getDeclaredFields();
List<String> expectedFieldNames = Arrays.asList(new String[] { "name",
"age" });
List<String> actualFieldNames = new ArrayList<>();
for (Field field : fields)
actualFieldNames.add(field.getName());
List<String> actualFieldNames = getFieldNames(fields);
assertTrue(expectedFieldNames.containsAll(actualFieldNames));
assertTrue(Arrays.asList("name", "age")
.containsAll(actualFieldNames));
}
@ -29,6 +28,7 @@ public class ReflectionTest {
public void givenObject_whenGetsClassName_thenCorrect() {
Object goat = new Goat("goat");
Class<?> clazz = goat.getClass();
assertEquals("Goat", clazz.getSimpleName());
assertEquals("com.baeldung.reflection.Goat", clazz.getName());
assertEquals("com.baeldung.reflection.Goat", clazz.getCanonicalName());
@ -38,6 +38,7 @@ public class ReflectionTest {
public void givenClassName_whenCreatesObject_thenCorrect()
throws ClassNotFoundException {
Class<?> clazz = Class.forName("com.baeldung.reflection.Goat");
assertEquals("Goat", clazz.getSimpleName());
assertEquals("com.baeldung.reflection.Goat", clazz.getName());
assertEquals("com.baeldung.reflection.Goat", clazz.getCanonicalName());
@ -50,6 +51,7 @@ public class ReflectionTest {
Class<?> animalClass = Class.forName("com.baeldung.reflection.Animal");
int goatMods = goatClass.getModifiers();
int animalMods = animalClass.getModifiers();
assertTrue(Modifier.isPublic(goatMods));
assertTrue(Modifier.isAbstract(animalMods));
assertTrue(Modifier.isPublic(animalMods));
@ -60,6 +62,7 @@ public class ReflectionTest {
Goat goat = new Goat("goat");
Class<?> goatClass = goat.getClass();
Package pkg = goatClass.getPackage();
assertEquals("com.baeldung.reflection", pkg.getName());
}
@ -83,6 +86,7 @@ public class ReflectionTest {
Class<?> animalClass = Class.forName("com.baeldung.reflection.Animal");
Class<?>[] goatInterfaces = goatClass.getInterfaces();
Class<?>[] animalInterfaces = animalClass.getInterfaces();
assertEquals(1, goatInterfaces.length);
assertEquals(1, animalInterfaces.length);
assertEquals("Locomotion", goatInterfaces[0].getSimpleName());
@ -94,6 +98,7 @@ public class ReflectionTest {
throws ClassNotFoundException {
Class<?> goatClass = Class.forName("com.baeldung.reflection.Goat");
Constructor<?>[] constructors = goatClass.getConstructors();
assertEquals(1, constructors.length);
assertEquals("com.baeldung.reflection.Goat", constructors[0].getName());
}
@ -103,13 +108,11 @@ public class ReflectionTest {
throws ClassNotFoundException {
Class<?> animalClass = Class.forName("com.baeldung.reflection.Animal");
Field[] fields = animalClass.getDeclaredFields();
List<String> expectedFields = Arrays.asList(new String[] { "name",
"CATEGORY" });
List<String> actualFields = new ArrayList<>();
for (Field field : fields)
actualFields.add(field.getName());
List<String> actualFields = getFieldNames(fields);
assertEquals(2, actualFields.size());
assertTrue(actualFields.containsAll(expectedFields));
assertTrue(actualFields.containsAll(Arrays.asList("name", "CATEGORY")));
}
@Test
@ -117,14 +120,11 @@ public class ReflectionTest {
throws ClassNotFoundException {
Class<?> animalClass = Class.forName("com.baeldung.reflection.Animal");
Method[] methods = animalClass.getDeclaredMethods();
List<String> expectedMethods = Arrays.asList(new String[] { "getName",
"setName", "getSound", "makeSound" });
List<String> actualMethods = new ArrayList<>();
for (Method method : methods)
actualMethods.add(method.getName());
assertEquals(4, actualMethods.size());
assertTrue(actualMethods.containsAll(expectedMethods));
List<String> actualMethods = getMethodNames(methods);
assertEquals(4, actualMethods.size());
assertTrue(actualMethods.containsAll(Arrays.asList("getName",
"setName", "getSound", "makeSound")));
}
@Test
@ -132,13 +132,13 @@ public class ReflectionTest {
throws ClassNotFoundException {
Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
Constructor<?>[] constructors = birdClass.getConstructors();
assertEquals(3, constructors.length);
}
@Test
public void givenClass_whenGetsEachConstructorByParamTypes_thenCorrect()
throws ClassNotFoundException, NoSuchMethodException,
SecurityException {
throws Exception {
Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
Constructor<?> cons1 = birdClass.getConstructor();
Constructor<?> cons2 = birdClass.getConstructor(String.class);
@ -148,17 +148,18 @@ public class ReflectionTest {
@Test
public void givenClass_whenInstantiatesObjectsAtRuntime_thenCorrect()
throws ClassNotFoundException, NoSuchMethodException,
SecurityException, InstantiationException, IllegalAccessException,
IllegalArgumentException, InvocationTargetException {
throws Exception {
Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
Constructor<?> cons1 = birdClass.getConstructor();
Constructor<?> cons2 = birdClass.getConstructor(String.class);
Constructor<?> cons3 = birdClass.getConstructor(String.class,
boolean.class);
Bird bird1 = (Bird) cons1.newInstance();
Bird bird2 = (Bird) cons2.newInstance("Weaver bird");
Bird bird3 = (Bird) cons3.newInstance("dove", true);
assertEquals("bird", bird1.getName());
assertEquals("Weaver bird", bird2.getName());
assertEquals("dove", bird3.getName());
@ -178,8 +179,7 @@ public class ReflectionTest {
@Test
public void givenClass_whenGetsPublicFieldByName_thenCorrect()
throws ClassNotFoundException, NoSuchFieldException,
SecurityException {
throws Exception {
Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
Field field = birdClass.getField("CATEGORY");
assertEquals("CATEGORY", field.getName());
@ -197,8 +197,7 @@ public class ReflectionTest {
@Test
public void givenClass_whenGetsFieldsByName_thenCorrect()
throws ClassNotFoundException, NoSuchFieldException,
SecurityException {
throws Exception {
Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
Field field = birdClass.getDeclaredField("walks");
assertEquals("walks", field.getName());
@ -207,8 +206,7 @@ public class ReflectionTest {
@Test
public void givenClassField_whenGetsType_thenCorrect()
throws ClassNotFoundException, NoSuchFieldException,
SecurityException {
throws Exception {
Field field = Class.forName("com.baeldung.reflection.Bird")
.getDeclaredField("walks");
Class<?> fieldClass = field.getType();
@ -217,8 +215,7 @@ public class ReflectionTest {
@Test
public void givenClassField_whenSetsAndGetsValue_thenCorrect()
throws ClassNotFoundException, NoSuchFieldException,
SecurityException, InstantiationException, IllegalAccessException {
throws Exception {
Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
Bird bird = (Bird) birdClass.newInstance();
Field field = birdClass.getDeclaredField("walks");
@ -236,8 +233,7 @@ public class ReflectionTest {
@Test
public void givenClassField_whenGetsAndSetsWithNull_thenCorrect()
throws ClassNotFoundException, InstantiationException,
IllegalAccessException, NoSuchFieldException, SecurityException {
throws Exception {
Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
Field field = birdClass.getField("CATEGORY");
field.setAccessible(true);
@ -250,12 +246,11 @@ public class ReflectionTest {
throws ClassNotFoundException {
Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
Method[] methods = birdClass.getMethods();
List<String> methodNames = new ArrayList<>();
for (Method method : methods)
methodNames.add(method.getName());
List<String> methodNames = getMethodNames(methods);
assertTrue(methodNames.containsAll(Arrays
.asList(new String[] { "equals", "notifyAll", "hashCode",
"walks", "eats", "toString" })));
.asList("equals", "notifyAll", "hashCode",
"walks", "eats", "toString")));
}
@ -263,12 +258,10 @@ public class ReflectionTest {
public void givenClass_whenGetsOnlyDeclaredMethods_thenCorrect()
throws ClassNotFoundException {
Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
Method[] methods = birdClass.getDeclaredMethods();
List<String> expectedMethodNames = Arrays.asList(new String[] {
"setWalks", "walks", "getSound", "eats" });
List<String> actualMethodNames = new ArrayList<>();
for (Method method : methods)
actualMethodNames.add(method.getName());
List<String> actualMethodNames = getMethodNames(birdClass.getDeclaredMethods());
List<String> expectedMethodNames = Arrays.asList("setWalks", "walks", "getSound", "eats");
assertEquals(expectedMethodNames.size(), actualMethodNames.size());
assertTrue(expectedMethodNames.containsAll(actualMethodNames));
assertTrue(actualMethodNames.containsAll(expectedMethodNames));
@ -277,16 +270,18 @@ public class ReflectionTest {
@Test
public void givenMethodName_whenGetsMethod_thenCorrect()
throws ClassNotFoundException, NoSuchMethodException,
SecurityException {
throws Exception {
Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
Method walksMethod = birdClass.getDeclaredMethod("walks");
Method setWalksMethod = birdClass.getDeclaredMethod("setWalks",
boolean.class);
assertFalse(walksMethod.isAccessible());
assertFalse(setWalksMethod.isAccessible());
walksMethod.setAccessible(true);
setWalksMethod.setAccessible(true);
assertTrue(walksMethod.isAccessible());
assertTrue(setWalksMethod.isAccessible());
@ -294,23 +289,35 @@ public class ReflectionTest {
@Test
public void givenMethod_whenInvokes_thenCorrect()
throws ClassNotFoundException, NoSuchMethodException,
SecurityException, IllegalAccessException,
IllegalArgumentException, InvocationTargetException,
InstantiationException {
throws Exception {
Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
Bird bird = (Bird) birdClass.newInstance();
Method setWalksMethod = birdClass.getDeclaredMethod("setWalks",
boolean.class);
Method walksMethod = birdClass.getDeclaredMethod("walks");
boolean walks = (boolean) walksMethod.invoke(bird);
assertFalse(walks);
assertFalse(bird.walks());
setWalksMethod.invoke(bird, true);
boolean walks2 = (boolean) walksMethod.invoke(bird);
assertTrue(walks2);
assertTrue(bird.walks());
}
private static List<String> getMethodNames(Method[] methods) {
return Stream.of(methods)
.map((Method::getName))
.collect(toList());
}
private static List<String> getFieldNames(Field[] fields) {
return Stream.of(fields)
.map(Field::getName)
.collect(toList());
}
}