Add ReflectionUtil

test-utils-core/pom.xml

@@ -88,13 +88,12 @@
             <groupId>org.reflections</groupId>
             <artifactId>reflections</artifactId>
         </dependency>
-
-        <!-- Test dependencies -->
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
-            <scope>test</scope>
         </dependency>
+
+        <!-- Test dependencies -->
         <dependency>
             <groupId>com.btmatthews.hamcrest</groupId>
             <artifactId>hamcrest-matchers</artifactId>

test-utils-core/src/main/java/uk/gov/justice/services/test/utils/core/reflection/ReflectionUtil.java

@@ -0,0 +1,135 @@
+package uk.gov.justice.services.test.utils.core.reflection;
+
+
+import static java.util.Arrays.stream;
+import static java.util.Comparator.comparing;
+import static java.util.stream.Collectors.toList;
+
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.util.List;
+import java.util.Optional;
+
+import edu.umd.cs.findbugs.annotations.SuppressWarnings;
+
+public final class ReflectionUtil {
+
+    private ReflectionUtil() {
+    }
+
+    /**
+     * @param classWithMethods - class type
+     * @return - list of methods of the classWithMethods
+     */
+    public static List<Method> methodsOf(final Class<?> classWithMethods) {
+        return stream(classWithMethods.getDeclaredMethods()).filter(m -> !m.getName().contains("jacoco") && !m.getName().contains("lambda"))
+                .sorted(comparing(Method::getName))
+                .collect(toList());
+    }
+
+    /**
+     * returns first method of the given class
+     *
+     * @param classWithMethod - class type
+     * @return - first method of the given classWithMethod
+     */
+    public static Optional<Method> firstMethodOf(final Class<?> classWithMethod) {
+        final List<Method> methods = methodsOf(classWithMethod);
+
+        return methods.stream().findFirst();
+    }
+
+    /**
+     * Returns method of the given class with the given name
+     *
+     * @param classWithMethod - class type
+     * @param methodName      - name of method in class
+     * @return -  method of the given class with the given name
+     */
+    public static Optional<Method> methodOf(final Class<?> classWithMethod, final String methodName) {
+        return methodsOf(classWithMethod).stream()
+                .filter(method -> method.getName().equals(methodName))
+                .findFirst();
+    }
+
+    /**
+     * Get the method of a Class with the given annotation.  Returns Optional.empty() if no method
+     * found.
+     *
+     * @param classWithMethod - the Class with the annotated method
+     * @param annotationClass - the Annotation Class to find
+     * @return the Method with the given annotation
+     */
+    public static Optional<Method> annotatedMethod(final Class<?> classWithMethod, final Class<? extends Annotation> annotationClass) {
+        return stream(classWithMethod.getDeclaredMethods())
+                .filter(method -> method.isAnnotationPresent(annotationClass))
+                .findFirst();
+    }
+
+    /**
+     * sets value of the field by reflection
+     *
+     * @param object     - object to modify
+     * @param fieldName  - name of the field belonging to the object
+     * @param fieldValue - value of the field to be set
+     * @throws IllegalAccessException if unable to access field
+     */
+    public static void setField(final Object object, final String fieldName, final Object fieldValue)
+            throws IllegalAccessException {
+        final Optional<Field> field = fieldOf(object.getClass(), fieldName);
+
+        if (field.isPresent()) {
+            field.get().setAccessible(true);
+            field.get().set(object, fieldValue);
+        }
+    }
+
+    /**
+     * Searches for a field in the given class by reflection
+     *
+     * @param classWithField - class type
+     * @param fieldName      - name of field in class
+     * @return - field belonging to the given classWithField with the given fieldName
+     */
+    public static Optional<Field> fieldOf(final Class<?> classWithField, final String fieldName) {
+        return stream(classWithField.getDeclaredFields())
+                .filter(f -> f.getName().equals(fieldName))
+                .findFirst();
+    }
+
+    /**
+     * Get the value of a field from an Object
+     *
+     * @param object          - object to find value from
+     * @param fieldName       - name of field in class
+     * @param returnClassType - defines the return field value class type
+     * @param <T>             the class type to return
+     * @return the field value returned cast to the class type defined by the returnClassType
+     */
+    public static <T> Optional<T> fieldValue(final Object object,
+                                             final String fieldName,
+                                             @SuppressWarnings("unused") final Class<T> returnClassType) throws IllegalAccessException {
+        return fieldValue(object, fieldName)
+                .map(o -> (T) o);
+    }
+
+    /**
+     * Get the value of a field from an Object
+     *
+     * @param object    - object to find value from
+     * @param fieldName - name of field in class
+     * @return - field belonging to the given clazz with the given fieldName
+     */
+    public static Optional<Object> fieldValue(final Object object, final String fieldName) throws IllegalAccessException {
+        final Optional<Field> field = fieldOf(object.getClass(), fieldName);
+
+        if (field.isPresent()) {
+            field.get().setAccessible(true);
+
+            return Optional.ofNullable(field.get().get(object));
+        }
+
+        return Optional.empty();
+    }
+}

test-utils-core/src/test/java/uk/gov/justice/services/test/utils/core/reflection/ReflectionUtilTest.java

@@ -0,0 +1,111 @@
+package uk.gov.justice.services.test.utils.core.reflection;
+
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+import static net.trajano.commons.testing.UtilityClassTestUtil.assertUtilityClassWellDefined;
+import static org.hamcrest.CoreMatchers.instanceOf;
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+import java.lang.reflect.Method;
+import java.util.List;
+import java.util.Optional;
+
+import org.junit.Test;
+
+public class ReflectionUtilTest {
+
+    @Test
+    public void shouldBeWellDefinedUtilityClass() {
+        assertUtilityClassWellDefined(ReflectionUtil.class);
+    }
+
+    @Test
+    public void shouldReturnListOfMethods() throws Exception {
+        final List<Method> methods = ReflectionUtil.methodsOf(TestClass.class);
+
+        assertThat(methods.size(), is(2));
+        assertThat(methods.get(0).getName(), is("method1"));
+        assertThat(methods.get(1).getName(), is("method2"));
+    }
+
+    @Test
+    public void shouldReturnTheFirstMethod() throws Exception {
+        final Optional<Method> method = ReflectionUtil.firstMethodOf(TestClass.class);
+
+        assertThat(method.isPresent(), is(true));
+        assertThat(method.get().getName(), is("method1"));
+    }
+
+    @Test
+    public void shouldReturnTheNamedMethod() throws Exception {
+        final Optional<Method> method = ReflectionUtil.methodOf(TestClass.class, "method2");
+
+        assertThat(method.isPresent(), is(true));
+        assertThat(method.get().getName(), is("method2"));
+    }
+
+    @Test
+    public void shouldReturnAnnotatedMethod() throws Exception {
+        final Optional<Method> method = ReflectionUtil.annotatedMethod(AnnotatedTestClass.class, TestAnnotation.class);
+
+        assertThat(method.isPresent(), is(true));
+        assertThat(method.get().getName(), is("method2"));
+    }
+
+    @Test
+    public void shouldReturnOptionalEmptyIfNoMethodWithAnnotation() throws Exception {
+        final Optional<Method> method = ReflectionUtil.annotatedMethod(TestClass.class, TestAnnotation.class);
+
+        assertThat(method, is(Optional.empty()));
+    }
+
+    @Test
+    public void shouldGetAndSetFieldValues() throws Exception {
+        final TestClass testClass = new TestClass();
+
+        final Optional<Object> fieldValue = ReflectionUtil.fieldValue(testClass, "field1");
+
+        assertThat(fieldValue.isPresent(), is(true));
+        assertThat(fieldValue.get(), is(instanceOf(String.class)));
+        assertThat(fieldValue.get(), is("value1"));
+
+        ReflectionUtil.setField(testClass, "field1", "new value");
+        final Optional<String> resultValue = ReflectionUtil.fieldValue(testClass, "field1", String.class);
+
+        assertThat(resultValue.isPresent(), is(true));
+        assertThat(resultValue.get(), is("new value"));
+    }
+
+    @Documented
+    @Target(METHOD)
+    @Retention(RUNTIME)
+    @interface TestAnnotation {
+    }
+
+    private class TestClass {
+
+        private String field1 = "value1";
+
+        public void method1() {
+        }
+
+        public boolean method2() {
+            return true;
+        }
+    }
+
+    private class AnnotatedTestClass {
+
+        public void method1() {
+        }
+
+        @TestAnnotation
+        public boolean method2() {
+            return true;
+        }
+    }
+}