/*
* This program is free software; you can redistribute it and/or modify it under the terms of
* the GNU AFFERO GENERAL PUBLIC LICENSE as published by the Free Software Foundation; either version 3 of the License,
* or (at your option) any later version.
*
* This program 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 AFFERO GENERAL PUBLIC LICENSE for more details.
* You should have received a copy of the GNU AFFERO GENERAL PUBLIC LICENSE along with this program;
* if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
package com.meidusa.amoeba.bean;
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.Method;
import java.lang.reflect.Modifier;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import com.meidusa.amoeba.util.JVM;
/**
* 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.
* 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>
*/
@SuppressWarnings("unchecked")
public class PureJavaReflectionProvider implements ReflectionProvider {
private transient Map serializedDataCache = Collections.synchronizedMap(new HashMap());
protected transient FieldDictionary fieldDictionary = new FieldDictionary();
public Object newInstance(Class type) {
try {
Constructor[] constructors = type.getDeclaredConstructors();
for (int i = 0; i < constructors.length; i++) {
if (constructors[i].getParameterTypes().length == 0) {
if (!Modifier.isPublic(constructors[i].getModifiers())) {
constructors[i].setAccessible(true);
}
return constructors[i].newInstance(new Object[0]);
}
}
if (Serializable.class.isAssignableFrom(type)) {
return instantiateUsingSerialization(type);
} else {
throw new ObjectAccessException("Cannot construct " + type.getName()
+ " as it does not have a no-args constructor");
}
} catch (InstantiationException e) {
throw new ObjectAccessException("Cannot construct " + type.getName(), e);
} catch (IllegalAccessException e) {
throw new ObjectAccessException("Cannot construct " + type.getName(), e);
} catch (InvocationTargetException e) {
if (e.getTargetException() instanceof RuntimeException) {
throw (RuntimeException)e.getTargetException();
} else if (e.getTargetException() instanceof Error) {
throw (Error)e.getTargetException();
} else {
throw new ObjectAccessException("Constructor for " + type.getName() + " threw an exception", e.getTargetException());
}
}
}
private Object instantiateUsingSerialization(Class type) {
try {
byte[] data;
if (serializedDataCache.containsKey(type)) {
data = (byte[]) serializedDataCache.get(type);
} else {
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));
return in.readObject();
} catch (IOException e) {
throw new ObjectAccessException("Cannot create " + type.getName() + " by JDK serialization", e);
} catch (ClassNotFoundException e) {
throw new ObjectAccessException("Cannot find class " + e.getMessage());
}
}
public void visitSerializableFields(Object object, ReflectionProvider.Visitor visitor) {
for (Iterator iterator = fieldDictionary.serializableFieldsFor(object.getClass()); iterator.hasNext();) {
Field field = (Field) iterator.next();
if (!fieldModifiersSupported(field)) {
continue;
}
validateFieldAccess(field);
try {
Object value = field.get(object);
visitor.visit(field.getName(), field.getType(), field.getDeclaringClass(), value);
} catch (IllegalArgumentException e) {
throw new ObjectAccessException("Could not get field " + field.getClass() + "." + field.getName(), e);
} catch (IllegalAccessException e) {
throw new ObjectAccessException("Could not get field " + field.getClass() + "." + field.getName(), e);
}
}
}
public void writeField(Object object, String fieldName, Object value, Class definedIn) {
Field field = fieldDictionary.field(object.getClass(), fieldName, definedIn);
validateFieldAccess(field);
try {
field.set(object, value);
} catch (IllegalArgumentException e) {
throw new ObjectAccessException("Could not set field " +field.getName()+"@"+ object.getClass() , e);
} catch (IllegalAccessException e) {
throw new ObjectAccessException("Could not set field " +field.getName()+"@"+ object.getClass() , e);
}
}
public void invokeMethod(Object object, String methodName, Object value, Class definedIn) {
try {
Method method = object.getClass().getMethod(methodName,new Class[]{value.getClass()});
method.invoke(object,new Object[]{value});
} catch (Exception e) {
throw new ObjectAccessException("Could not invoke " + object.getClass() + "." + methodName, e);
}
}
public Class getFieldType(Object object, String fieldName, Class definedIn) {
return fieldDictionary.field(object.getClass(), fieldName, definedIn).getType();
}
public boolean fieldDefinedInClass(String fieldName, Class type) {
try {
Field field = fieldDictionary.field(type, fieldName, null);
return fieldModifiersSupported(field);
} catch (ObjectAccessException e) {
return false;
}
}
protected boolean fieldModifiersSupported(Field field) {
return !(Modifier.isStatic(field.getModifiers())
|| Modifier.isTransient(field.getModifiers()));
}
protected void validateFieldAccess(Field field) {
if (Modifier.isFinal(field.getModifiers())) {
if (JVM.is15()) {
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);
}
protected Object readResolve() {
serializedDataCache = Collections.synchronizedMap(new HashMap());
fieldDictionary = new FieldDictionary();
return this;
}
}