/*
* Copyright (C) 2004, 2005, 2006 Joe Walnes.
* Copyright (C) 2006, 2007, 2009, 2011, 2013, 2016, 2018 XStream Committers.
* All rights reserved.
*
* The software in this package is published under the terms of the BSD
* style license a copy of which has been included with this distribution in
* the LICENSE.txt file.
*
* Created on 07. March 2004 by Joe Walnes
*/
package com.thoughtworks.xstream.converters.reflection;
import com.thoughtworks.xstream.core.JVM;
import com.thoughtworks.xstream.core.util.Fields;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectStreamClass;
import java.io.ObjectStreamConstants;
import java.io.Serializable;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Modifier;
import java.util.Iterator;
import java.util.Map;
import java.util.WeakHashMap;
/**
* Pure Java ObjectFactory that instantiates objects using standard Java reflection, however the types of objects
* that can be constructed are limited.
* <p>
* Can newInstance: classes with public visibility, outer classes, static inner classes, classes with default constructors
* and any class that implements java.io.Serializable.
* </p>
* <p>
* Cannot newInstance: classes without public visibility, non-static inner classes, classes without default constructors.
* Note that any code in the constructor of a class will be executed when the ObjectFactory instantiates the object.
* </p>
* @author Joe Walnes
*/
public class PureJavaReflectionProvider implements ReflectionProvider {
private transient Map serializedDataCache;
protected FieldDictionary fieldDictionary;
public PureJavaReflectionProvider() {
this(new FieldDictionary(new ImmutableFieldKeySorter()));
}
public PureJavaReflectionProvider(FieldDictionary fieldDictionary) {
this.fieldDictionary = fieldDictionary;
init();
}
public Object newInstance(Class type) {
ObjectAccessException oaex = null;
try {
Constructor[] constructors = type.getDeclaredConstructors();
for (int i = 0; i < constructors.length; i++) {
final Constructor constructor = constructors[i];
if (constructor.getParameterTypes().length == 0) {
if (!constructor.isAccessible()) {
constructor.setAccessible(true);
}
return constructor.newInstance(new Object[0]);
}
}
if (Serializable.class.isAssignableFrom(type)) {
return instantiateUsingSerialization(type);
} else {
oaex = new ObjectAccessException("Cannot construct type as it does not have a no-args constructor");
}
} catch (InstantiationException e) {
oaex = new ObjectAccessException("Cannot construct type", e);
} catch (IllegalAccessException e) {
oaex = new ObjectAccessException("Cannot construct type", e);
} catch (InvocationTargetException e) {
if (e.getTargetException() instanceof RuntimeException) {
throw (RuntimeException)e.getTargetException();
} else if (e.getTargetException() instanceof Error) {
throw (Error)e.getTargetException();
} else {
oaex = new ObjectAccessException("Constructor for type threw an exception", e.getTargetException());
}
}
oaex.add("construction-type", type.getName());
throw oaex;
}
private Object instantiateUsingSerialization(final Class type) {
ObjectAccessException oaex = null;
try {
synchronized (serializedDataCache) {
byte[] data = (byte[]) serializedDataCache.get(type);
if (data == null) {
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
DataOutputStream stream = new DataOutputStream(bytes);
stream.writeShort(ObjectStreamConstants.STREAM_MAGIC);
stream.writeShort(ObjectStreamConstants.STREAM_VERSION);
stream.writeByte(ObjectStreamConstants.TC_OBJECT);
stream.writeByte(ObjectStreamConstants.TC_CLASSDESC);
stream.writeUTF(type.getName());
stream.writeLong(ObjectStreamClass.lookup(type).getSerialVersionUID());
stream.writeByte(2); // classDescFlags (2 = Serializable)
stream.writeShort(0); // field count
stream.writeByte(ObjectStreamConstants.TC_ENDBLOCKDATA);
stream.writeByte(ObjectStreamConstants.TC_NULL);
data = bytes.toByteArray();
serializedDataCache.put(type, data);
}
ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(data)) {
protected Class resolveClass(ObjectStreamClass desc)
throws IOException, ClassNotFoundException {
return Class.forName(desc.getName(), false, type.getClassLoader());
}
};
return in.readObject();
}
} catch (IOException e) {
oaex = new ObjectAccessException("Cannot create type by JDK serialization", e);
} catch (ClassNotFoundException e) {
oaex = new ObjectAccessException("Cannot find class", e);
}
oaex.add("construction-type", type.getName());
throw oaex;
}
public void visitSerializableFields(Object object, ReflectionProvider.Visitor visitor) {
for (Iterator iterator = fieldDictionary.fieldsFor(object.getClass()); iterator.hasNext();) {
Field field = (Field) iterator.next();
if (!fieldModifiersSupported(field)) {
continue;
}
validateFieldAccess(field);
Object value = Fields.read(field, object);
visitor.visit(field.getName(), field.getType(), field.getDeclaringClass(), value);
}
}
public void writeField(Object object, String fieldName, Object value, Class definedIn) {
Field field = fieldDictionary.field(object.getClass(), fieldName, definedIn);
validateFieldAccess(field);
Fields.write(field, object, value);
}
public Class getFieldType(Object object, String fieldName, Class definedIn) {
return fieldDictionary.field(object.getClass(), fieldName, definedIn).getType();
}
/**
* @deprecated As of 1.4.5, use {@link #getFieldOrNull(Class, String)} instead
*/
public boolean fieldDefinedInClass(String fieldName, Class type) {
Field field = fieldDictionary.fieldOrNull(type, fieldName, null);
return field != null && fieldModifiersSupported(field);
}
protected boolean fieldModifiersSupported(Field field) {
int modifiers = field.getModifiers();
return !(Modifier.isStatic(modifiers) || Modifier.isTransient(modifiers));
}
protected void validateFieldAccess(Field field) {
if (Modifier.isFinal(field.getModifiers())) {
if (JVM.isVersion(5)) {
if (!field.isAccessible()) {
field.setAccessible(true);
}
} else {
throw new ObjectAccessException("Invalid final field "
+ field.getDeclaringClass().getName() + "." + field.getName());
}
}
}
public Field getField(Class definedIn, String fieldName) {
return fieldDictionary.field(definedIn, fieldName, null);
}
public Field getFieldOrNull(Class definedIn, String fieldName) {
return fieldDictionary.fieldOrNull(definedIn, fieldName, null);
}
public void setFieldDictionary(FieldDictionary dictionary) {
this.fieldDictionary = dictionary;
}
private Object readResolve() {
init();
return this;
}
protected void init() {
serializedDataCache = new WeakHashMap();
}
}