1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
|
/*
* Copyright (c) 2004 - 2012 Eike Stepper (Berlin, Germany) and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Simon McDuff - initial API and implementation
* Eike Stepper - maintenance
*/
package org.eclipse.emf.cdo.view;
import org.eclipse.emf.cdo.common.id.CDOID;
import org.eclipse.emf.cdo.util.CDOUtil;
import org.eclipse.emf.cdo.util.ObjectNotFoundException;
import org.eclipse.emf.internal.cdo.messages.Messages;
import org.eclipse.emf.ecore.EClassifier;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.EStructuralFeature;
import org.eclipse.emf.ecore.InternalEObject;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
/**
* Specifies a policy on how to deal with stale references.
*
* @author Simon McDuff
* @since 3.0
*/
public interface CDOStaleReferencePolicy
{
/**
* A default stale reference policy. It will throw an exception each time.
*/
public static final CDOStaleReferencePolicy EXCEPTION = new CDOStaleReferencePolicy()
{
public Object processStaleReference(EObject source, EStructuralFeature feature, int index, CDOID target)
{
throw new ObjectNotFoundException(target);
}
@Override
public String toString()
{
return Messages.getString("CDOStaleReferencePolicy.0"); //$NON-NLS-1$
}
};
/**
* Returns a proxy object with the appropriate EClass. The proxy object supports the {@link InternalEObject#eClass()
* eClass()} and {@link InternalEObject#eIsProxy() eIsProxy()} methods. For all invocations to other methods the proxy
* object throws an {@link ObjectNotFoundException}. The receiver can use {@link CDOUtil#isStaleObject(Object)} to
* detect proxy objects.
*/
public static final CDOStaleReferencePolicy PROXY = new CDOStaleReferencePolicy()
{
public Object processStaleReference(EObject source, final EStructuralFeature feature, int index, final CDOID target)
{
final EClassifier type = feature.getEType();
InvocationHandler handler = new InvocationHandler()
{
public Object invoke(Object arg0, Method arg1, Object[] arg2) throws Throwable
{
if (arg1.getName().equals("eIsProxy")) //$NON-NLS-1$
{
return false;
}
if (arg1.getName().equals("eClass")) //$NON-NLS-1$
{
return type;
}
throw new ObjectNotFoundException(target);
}
};
Class<?> instanceClass = type.getInstanceClass();
Class<?>[] interfaces = null;
// Be sure to have only interface
if (instanceClass.isInterface())
{
interfaces = new Class<?>[] { instanceClass, InternalEObject.class, CDOStaleObject.class };
}
else
{
interfaces = new Class<?>[] { InternalEObject.class, CDOStaleObject.class };
}
return Proxy.newProxyInstance(instanceClass.getClassLoader(), interfaces, handler);
}
@Override
public String toString()
{
return Messages.getString("CDOStaleReferencePolicy.1"); //$NON-NLS-1$
}
};
/**
* Returns an object that we want to return to the caller (clients). Exception thrown will be received by the caller
* (clients).
*/
public Object processStaleReference(EObject source, EStructuralFeature feature, int index, CDOID target);
}
|
