Hi Ian,
or you use attached class as a base to make shallow clones.
Regards
Ralf
Simon Lord schrieb:
Have a read of this article:
http://www.javaworld.com/javaworld/javatips/jw-javatip76.html
It provides a class for doing deep copies of serializable objects (of
which castor objects are - i think!).
The article ends saying that it's not the fastest deep copy, but it is
very generic.
Hope that helps
Simon Lord
Ian Stokes-Rees wrote:
Hi,
Is there some easy/obvious way to make a copy of a Java object which
has been created out of an XML Schema definition? I have managed to
do this by piping marshall into unmarshall, but I need to write a
method for every object I want to copy (see example below).
Thanks,
Ian
<xs:element name="Algorithm">
<xs:complexType>
<xs:attribute name="timeIntervalsPerYear" type="xs:long"
use="required" />
<xs:attribute name="type" type="xs:string" use="required">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="EuropeanSimple"/>
<xs:enumeration value="EuropeanBarrier"/>
<xs:enumeration value="EuropeanBasket"/>
</xs:restriction>
</xs:simpleType>
</xs:attribute>
<xs:attribute name="iterations" type="xs:double" use="required" />
<xs:attribute name="queuedIts" type="xs:double" use="optional" />
</xs:complexType>
</xs:element>
<Algorithm
type="EuropeanSimple"
timeIntervalsPerYear="50"
iterations="1e5"
/>
static public Algorithm copyAlgorithm(Algorithm alg) {
Algorithm new_alg = new Algorithm();
try {
PipedReader reader = new PipedReader();
PipedWriter writer = new PipedWriter(reader);
alg.marshal(writer);
writer.close();
new_alg =
(Algorithm)Unmarshaller.unmarshal(Algorithm.class, reader);
} catch (Exception ex) {
log.error("Could not copy object");
ex.printStackTrace();
}
return new_alg;
}
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Geschäftsleitung: Jens Joachim, Ralf Joachim
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Modifier;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public final class Cloner {
private static final Log LOG = LogFactory.getLog(Cloner.class);
public Cloner() { }
public Object clone(final Object origin) {
if (origin == null) {
throw new NullPointerException("parameter 'origin' must not be null");
}
Object target = null;
try {
Constructor c = origin.getClass().getDeclaredConstructor(null);
c.setAccessible(true);
target = c.newInstance(null);
} catch (InvocationTargetException e) {
String msg = "Unable to reproduce specified origin " + origin.getClass().getName();
msg += ". Cause: " + e.getCause().getClass().getName() + ". Check default constructor.";
throw new IllegalArgumentException(msg);
} catch (Exception e) {
String msg = "Unable to reproduce specified origin " + origin.getClass().getName();
msg += ". Cause: " + e.getClass().getName() + ". Check default constructor.";
throw new IllegalArgumentException(msg);
}
copyAllDeclaredFields(origin.getClass(), origin, target);
return target;
}
protected void copyAllDeclaredFields(final Class cls, final Object origin,
final Object target) {
if (cls == null) { return; }
copyDeclaredFields(cls, origin, target);
copyAllDeclaredFields(cls.getSuperclass(), origin, target);
}
protected void copyDeclaredFields(final Class cls, final Object origin, final Object target) {
if (cls == null) { return; }
Field[] fields = cls.getDeclaredFields();
Field.setAccessible(fields, true);
try {
for (int i = 0; i < fields.length; i++) {
// transient and final properties must not be copied:
if (((fields[i].getModifiers() & Modifier.TRANSIENT) == 0)
&& ((fields[i].getModifiers() & Modifier.FINAL) == 0)) {
Object value = fields[i].get(origin);
// deep copy for cloneable objects (like ArrayList, etc.)
if (value instanceof Cloneable) {
try {
fields[i].set(target, value.getClass().getMethod("clone", null)
.invoke(value, null));
} catch (Exception e) {
String msg = "Cloning of field " + fields[i].getName() + " for "
+ origin.getClass().getName() + " failed.";
LOG.error(msg, e);
}
} else {
fields[i].set(target, value);
}
}
}
} catch (IllegalAccessException e) {
// Should not happen, cause fields are set accessible before accessing them
e.printStackTrace();
}
}
public boolean isEqual(final Object obj1, final Object obj2) {
if (obj1 == obj2) { return true; }
if (obj1.getClass() != obj2.getClass()) { return false; }
return areAllDeclaredFieldsEqual(obj1.getClass(), obj1, obj2);
}
protected boolean areAllDeclaredFieldsEqual(final Class cls,
final Object obj1, final Object obj2) {
if (cls == null) { return true; }
if (areDeclaredFieldsEqual(cls, obj1, obj2)) {
return areAllDeclaredFieldsEqual(cls.getSuperclass(), obj1, obj2);
} else {
return false;
}
}
protected boolean areDeclaredFieldsEqual(final Class cls,
final Object obj1, final Object obj2) {
Field[] fields = cls.getDeclaredFields();
Field.setAccessible(fields, true);
try {
for (int i = 0; i < fields.length; i++) {
// transient and final properties must not be considered:
if (((fields[i].getModifiers() & Modifier.TRANSIENT) == 0)
&& ((fields[i].getModifiers() & Modifier.FINAL) == 0)) {
// TODO remove next line when timestamp is mapped to database
if (!fields[i].getName().equals("_jdoTimeStamp")) {
// For java.lang.reflect.Proxy do not compare their InvocationHandlers
if (!fields[i].getName().equals("h")) {
Object value1 = fields[i].get(obj1);
Object value2 = fields[i].get(obj2);
if (!ReproHelpers.isEqual(value1, value2)) {
if (LOG.isDebugEnabled()) {
LOG.debug("Field " + fields[i].getName() + " unequals for "
+ obj1.getClass().getName()
+ " (" + value1 + " / " + value2 + ")");
}
return false;
}
}
}
}
}
} catch (IllegalAccessException e) {
// Should not happen, cause fields are set accessible before accessing them
e.printStackTrace();
}
return true;
}
}
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