Hi,
Can anyone please tell me why this code doesn't seem to have an effect?
That is I get a class cast exception because an encrypted object for
example EncryptedCostCentre does not get decrypted to a CostCentre. Both
classes implement an interface called ICostCentre, but this interface
has no method signatures etc as the structure of the two classes is
different. I.e. CostCentre has getter/setters and EncryptedCostCentre
has an encrypt and decrypt methods.
The concept works fine, if I override the java.util.List methods and
encrypt and decrypt there, but this isn't really practical as I can
override methods such as indexOf(Object o) as they rely on equals.
The cypherMachine and encryptedClassType are set in the decrypt method
of the owner object, where a reference to the ICostCentre collection is
passed to the decrypted version of that object.
Also what changes am I likely to need to make to the afterStore method?
Thanks,
Robert Giddings
The code:
package com.netcase.database.ojb.proxy;
import java.lang.reflect.Method;
import java.util.Iterator;
import org.apache.ojb.broker.ManageableCollection;
import org.apache.ojb.broker.PBKey;
import org.apache.ojb.broker.PersistenceBroker;
import org.apache.ojb.broker.PersistenceBrokerException;
import org.apache.ojb.broker.core.proxy.ListProxyDefaultImpl;
import org.apache.ojb.broker.query.Query;
import com.netcase.encryption.CypherMachine;
public class EncryptableCollectionProxy extends ListProxyDefaultImpl {
private CypherMachine cypherMachine;
private Class encryptedClassType;
public EncryptableCollectionProxy(PBKey brokerKey,
java.lang.Class collClass, Query query) {
super(brokerKey, collClass, query);
cypherMachine = null;
encryptedClassType = null;
}
public EncryptableCollectionProxy(PBKey brokerKey, Query query)
{
super(brokerKey, query);
cypherMachine = null;
encryptedClassType = null;
}
/**
* @return the cypherMachine
*/
public CypherMachine getCypherMachine() {
return cypherMachine;
}
/**
* @param cypherMachine the cypherMachine to set
*/
public void setCypherMachine(CypherMachine cypherMachine) {
this.cypherMachine = cypherMachine;
}
/**
* @return the encryptedClassType
*/
public Class getEncryptedClassType() {
return encryptedClassType;
}
/**
* @param encryptedClassType the encryptedClassType to set
*/
public void setEncryptedClassType(Class encryptedClassType) {
this.encryptedClassType = encryptedClassType;
}
private Object decryptObject(Object o) {
try {
Method decrypt =
encryptedClassType.getMethod("decrypt", CypherMachine.class);
return decrypt.invoke(o, cypherMachine);
}
catch(Exception e) {
return null;
}
}
private Object encryptObject(Object o) {
try {
Method encrypt =
encryptedClassType.getMethod("encrypt", CypherMachine.class);
return encrypt.invoke(o, cypherMachine);
}
catch(Exception e) {
return null;
}
}
public void ojbAdd(Object anObject) {
super.ojbAdd(this.decryptObject(anObject));
}
public void ojbAddAll(ManageableCollection otherCollection) {
Iterator i = otherCollection.ojbIterator();
while(i.hasNext()) {
this.ojbAdd(i.next());
}
}
public Iterator ojbIterator() {
EncryptableCollectionProxy ecp =
new
EncryptableCollectionProxy(this.getBrokerKey(),
this.getCollectionClass(),
this.getQuery());
for(Object o: this) {
ecp.add(this.encryptObject(o));
}
return ecp.ojbIterator();
}
public void afterStore(PersistenceBroker broker) throws
PersistenceBrokerException {
super.afterStore(broker);
}
}
An example of the XDoclet code is:
/**
* @ojb.collection
element-class-ref="com.netcase.netspat.recordSystem.encryption.encrypted
Objects.EncryptedCostCentre"
* foreignkey="clientId"
* proxy="true"
* auto-retrieve="true"
* auto-update="none"
* auto-delete="none"
*/
private Collection<ICostCentre> costCentres;
Use of code:
public Client decrypt(CypherMachine cm) throws FailedDecryptionException
{
Client c = new Client(this.id);
try {
...
EncryptableCollectionProxy costCentresProxy =
(EncryptableCollectionProxy)costCentres;
costCentresProxy.setCypherMachine(cm);
costCentresProxy.setEncryptedClassType(EncryptedCostCentre.class);
c.setCostCentres(costCentresProxy);
...
return c;
} catch(Exception e) {
throw new FailedDecryptionException("Unable to
decrypt encrypted client: " + this.toString(), e);
}
}
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