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JaVers - object auditing and diff framework for Java
package org.javers.common.reflection;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
/**
* @author bartosz walacik
*/
class JaversGetterFactory {
private final Class getterSource;
private final List getters = new ArrayList<>();
private final TypeResolvingContext context = new TypeResolvingContext();
JaversGetterFactory(Class getterSource) {
this.getterSource = getterSource;
}
/**
* List all class getters, including inherited and private.
*/
List getAllGetters() {
if (getters.size() > 0) {
throw new IllegalStateException("getters.size() > 0");
}
findAllGetters(getterSource);
return getters;
}
private void findAllGetters(Class currentGetterSource) {
Class clazz = currentGetterSource;
while (clazz != null && clazz != Object.class) {
context.addTypeSubstitutions(clazz);
Arrays.stream(clazz.getDeclaredMethods())
.filter(method -> isGetter(method) && !method.isBridge())
.filter(method -> !isOverridden(method, getters))
.map(getter -> createJaversGetter(getter, context))
.forEach(getters::add);
clazz = clazz.getSuperclass();
}
clazz = currentGetterSource;
while (clazz != null && clazz != Object.class) {
Arrays.stream(clazz.getInterfaces()).forEach(this::findAllGetters);
clazz = clazz.getSuperclass();
}
}
private static boolean isGetter(Method rawMethod) {
return hasGetOrIsPrefix(rawMethod) &&
hasNoParamters(rawMethod) &&
returnsSomething(rawMethod) &&
isNotStatic(rawMethod) &&
//isNotAbstract(rawMethod) &&
isNotNative(rawMethod);
}
private static boolean hasGetOrIsPrefix(Method rawMethod) {
return rawMethod.getName().startsWith("get") ||
rawMethod.getName().startsWith("is");
}
private static boolean hasNoParamters(Method rawMethod) {
return rawMethod.getParameterTypes().length == 0;
}
private static boolean returnsSomething(Method rawMethod) {
return rawMethod.getGenericReturnType() != void.class;
}
private static boolean isNotStatic(Method rawMethod) {
return !Modifier.isStatic(rawMethod.getModifiers());
}
private static boolean isNotNative(Method rawMethod) {
return !Modifier.isNative(rawMethod.getModifiers());
}
private static boolean isOverridden(Method parent, Collection toCheck) {
return toCheck.stream()
.map(it -> it.getRawMember())
.anyMatch(it -> isOverridden(parent, it));
}
private static boolean isOverridden(Method parent, Method toCheck) {
return isSubClass(parent, toCheck) &&
sameMethodName(parent, toCheck) &&
returnTypeCovariant(parent, toCheck) &&
sameArguments(parent, toCheck);
}
private static boolean isSubClass(final Method parent, final Method toCheck) {
return parent.getDeclaringClass().isAssignableFrom(toCheck.getDeclaringClass());
}
private static boolean sameMethodName(final Method parent, final Method toCheck) {
return parent.getName().equals(toCheck.getName());
}
private static boolean returnTypeCovariant(final Method parent, final Method toCheck) {
return parent.getReturnType().isAssignableFrom(toCheck.getReturnType());
}
private static boolean sameArguments(final Method parent, final Method toCheck) {
return Arrays.equals(parent.getParameterTypes(), toCheck.getParameterTypes());
}
private JaversGetter createJaversGetter(Method getterMethod, TypeResolvingContext context) {
Type actualReturnType = context.getSubstitution(getterMethod.getGenericReturnType());
if (hasInheritedId(getterMethod)) {
return new JaversGetter(getterMethod, actualReturnType, true);
}
return new JaversGetter(getterMethod, actualReturnType);
}
private static boolean hasInheritedId(Method concrete) {
List overridden = new ArrayList<>();
Class clazz = concrete.getDeclaringClass().getSuperclass();
while (clazz != null && clazz != Object.class) {
Arrays.asList(clazz.getDeclaredMethods())
.stream()
.filter(parent -> isOverridden(parent, concrete))
.findFirst().ifPresent(parent -> overridden.add(parent));
clazz = clazz.getSuperclass();
}
return overridden.stream().anyMatch(ReflectionUtil::looksLikeId);
}
}