/*
* Copyright (c) 2007, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Array;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Collection;
import java.util.IdentityHashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Queue;
import java.util.SortedMap;
import java.util.SortedSet;
final class BeanValidator {
private final Map<Object, Object> cache = new IdentityHashMap<Object, Object>();
public void validate(Object object1, Object object2) {
// compare references
if (object1 == object2) {
return;
}
// check for null
if ((object1 == null) || (object2 == null)) {
throw new IllegalStateException("could not compare object with null");
}
// resolve self references
if (isCyclic(object1, object2)) {
return;
}
// resolve cross references
if (isCyclic(object2, object1)) {
return;
}
Class type = object1.getClass();
if (!type.equals(object2.getClass())) {
throw new IllegalStateException("could not compare objects with different types");
}
// validate elements of arrays
if (type.isArray()) {
int length = Array.getLength(object1);
if (length != Array.getLength(object2)) {
throw new IllegalStateException("could not compare arrays with different lengths");
}
try {
this.cache.put(object1, object2);
for (int i = 0; i < length; i++) {
log("validate array element", Integer.valueOf(i));
validate(Array.get(object1, i), Array.get(object2, i));
}
} finally {
this.cache.remove(object1);
}
return;
}
// validate objects using equals()
// we assume that the method equals(Object) can be called,
// if the class declares such method
if (isDefined(type, "equals", Object.class)) {
if (object1.equals(object2)) {
return;
}
throw new IllegalStateException("the first object is not equal to the second one");
}
// validate comparable objects using compareTo()
// we assume that the method compareTo(Object) can be called,
// if the class declares such method and implements interface Comparable
if (Comparable.class.isAssignableFrom(type) && isDefined(type, "compareTo", Object.class)) {
Comparable cmp = (Comparable) object1;
if (0 == cmp.compareTo(object2)) {
return;
}
throw new IllegalStateException("the first comparable object is not equal to the second one");
}
try {
this.cache.put(object1, object2);
// validate values of public fields
for (Field field : getFields(type)) {
int mod = field.getModifiers();
if (!Modifier.isStatic(mod)) {
log("validate field", field.getName());
validate(object1, object2, field);
}
}
// validate values of properties
for (PropertyDescriptor pd : getDescriptors(type)) {
Method method = pd.getReadMethod();
if (method != null) {
log("validate property", pd.getName());
validate(object1, object2, method);
}
}
// validate contents of maps
if (SortedMap.class.isAssignableFrom(type)) {
validate((Map) object1, (Map) object2, true);
} else if (Map.class.isAssignableFrom(type)) {
validate((Map) object1, (Map) object2, false);
}
// validate contents of collections
if (SortedSet.class.isAssignableFrom(type)) {
validate((Collection) object1, (Collection) object2, true);
} else if (List.class.isAssignableFrom(type)) {
validate((Collection) object1, (Collection) object2, true);
} else if (Queue.class.isAssignableFrom(type)) {
validate((Collection) object1, (Collection) object2, true);
} else if (Collection.class.isAssignableFrom(type)) {
validate((Collection) object1, (Collection) object2, false);
}
} finally {
this.cache.remove(object1);
}
}
private void validate(Object object1, Object object2, Field field) {
try {
object1 = field.get(object1);
object2 = field.get(object2);
validate(object1, object2);
}
catch (IllegalAccessException exception) {
log(exception);
}
}
private void validate(Object object1, Object object2, Method method) {
try {
object1 = method.invoke(object1);
object2 = method.invoke(object2);
validate(object1, object2);
}
catch (IllegalAccessException exception) {
log(exception);
}
catch (InvocationTargetException exception) {
log(exception.getCause());
}
}
private void validate(Collection c1, Collection c2, boolean sorted) {
if (c1.size() != c2.size()) {
throw new IllegalStateException("could not compare collections with different sizes");
}
if (sorted) {
Iterator first = c1.iterator();
Iterator second = c2.iterator();
for (int i = 0; first.hasNext() && second.hasNext(); i++) {
log("validate collection element", Integer.valueOf(i));
validate(first.next(), second.next());
}
if (first.hasNext() || second.hasNext()) {
throw new IllegalStateException("one collection contains more elements than another one");
}
} else {
List list = new ArrayList(c2);
Iterator first = c1.iterator();
for (int i = 0; first.hasNext(); i++) {
Object value = first.next();
log("validate collection element", Integer.valueOf(i));
Iterator second = list.iterator();
for (int j = 0; second.hasNext(); j++) {
log("validate collection element against", Integer.valueOf(j));
try {
validate(value, second.next());
second.remove();
break;
} catch (IllegalStateException exception) {
if (!second.hasNext()) {
throw new IllegalStateException("one collection does not contain some elements from another one", exception);
}
}
}
}
}
}
private void validate(Map map1, Map map2, boolean sorted) {
if (map1.size() != map2.size()) {
throw new IllegalStateException("could not compare maps with different sizes");
}
if (sorted) {
Iterator first = map1.entrySet().iterator();
Iterator second = map2.entrySet().iterator();
int index = 0;
while (first.hasNext() && second.hasNext()) {
log("validate map entry", Integer.valueOf(index++));
validate(first.next(), second.next());
}
if (first.hasNext() || second.hasNext()) {
throw new IllegalStateException("one map contains more entries than another one");
}
} else {
// assume that equals() can be used for keys
for (Object key : map1.keySet()) {
log("validate map value for key", key);
validate(map1.get(key), map2.get(key));
}
}
}
private boolean isCyclic(Object object1, Object object2) {
Object object = this.cache.get(object1);
if (object == null) {
return false;
}
if (object == object2) {
return true;
}
throw new IllegalStateException("could not resolve cyclic reference");
}
private boolean isDefined(Class type, String name, Class... params) {
try {
return type.equals(type.getMethod(name, params).getDeclaringClass());
}
catch (NoSuchMethodException exception) {
log(exception);
}
catch (SecurityException exception) {
log(exception);
}
return false;
}
private static final Field[] FIELDS = {};
private Field[] getFields(Class type) {
try {
return type.getFields();
}
catch (SecurityException exception) {
log(exception);
}
return FIELDS;
}
private static final PropertyDescriptor[] DESCRIPTORS = {};
private PropertyDescriptor[] getDescriptors(Class type) {
try {
return Introspector.getBeanInfo(type, Object.class).getPropertyDescriptors();
}
catch (IntrospectionException exception) {
log(exception);
}
return DESCRIPTORS;
}
private final StringBuilder sb = new StringBuilder(1024);
private void log(String message, Object value) {
this.sb.setLength(0);
int size = this.cache.size();
while (0 < size--) {
this.sb.append(" ");
}
this.sb.append(" - ");
this.sb.append(message);
if (value != null) {
this.sb.append(": ");
this.sb.append(value);
}
System.out.println(this.sb.toString());
}
private void log(Throwable throwable) {
this.sb.setLength(0);
int size = this.cache.size();
while (0 < size--) {
this.sb.append(" ");
}
this.sb.append(" ? ");
this.sb.append(throwable);
System.out.println(this.sb.toString());
}
}