|
1
|
package eu.dnetlib.enabling.resultset;
|
|
2
|
|
|
3
|
import java.util.Map;
|
|
4
|
import java.util.WeakHashMap;
|
|
5
|
|
|
6
|
import eu.dnetlib.enabling.resultset.observer.DelegationObserver;
|
|
7
|
import eu.dnetlib.enabling.resultset.observer.Observable;
|
|
8
|
|
|
9
|
|
|
10
|
/**
|
|
11
|
* Common stuff for resultset implementations bound to a ResultSetRegistry.
|
|
12
|
*
|
|
13
|
* @author marko
|
|
14
|
*
|
|
15
|
*/
|
|
16
|
public abstract class AbstractObservableResultset implements ResultSet, Observable {
|
|
17
|
/**
|
|
18
|
* true if the resultset is destroyed.
|
|
19
|
*/
|
|
20
|
private boolean destroyed = false;
|
|
21
|
|
|
22
|
/**
|
|
23
|
* true if the resultset is open.
|
|
24
|
*/
|
|
25
|
private boolean open;
|
|
26
|
|
|
27
|
/**
|
|
28
|
* delegate the real job to a java.util.Observable object.
|
|
29
|
*/
|
|
30
|
private transient final java.util.Observable observable = new DelegationObservable();
|
|
31
|
|
|
32
|
/**
|
|
33
|
* weak map for removing single observers later on.
|
|
34
|
*/
|
|
35
|
private transient Map<ResultSetRegistry, DelegationObserver> observers = new WeakHashMap<ResultSetRegistry, DelegationObserver>();
|
|
36
|
|
|
37
|
/**
|
|
38
|
* java.util.Observable requires a "change" in the object to be made for the notifyObservers methods to trigger
|
|
39
|
* actually the notification. We don't think this should be part of the base Observable/Observer pattern and thus
|
|
40
|
* hide this fact. If an user of AbstractObservable wants this behavior it should implement her own change tracking
|
|
41
|
* and avoid calling notifyObservers altogether. The rationale behind this choice is that not all dirty states can
|
|
42
|
* be expressed using a stateful boolean instance variable like that implemented by java.util.Observable; some users
|
|
43
|
* may prefer/need a lazy dirty flag instead.
|
|
44
|
*
|
|
45
|
* @author marko
|
|
46
|
*
|
|
47
|
*/
|
|
48
|
static class DelegationObservable extends java.util.Observable {
|
|
49
|
|
|
50
|
/**
|
|
51
|
* {@inheritDoc}
|
|
52
|
*
|
|
53
|
* @see java.util.Observable#notifyObservers()
|
|
54
|
*/
|
|
55
|
@Override
|
|
56
|
public void notifyObservers() {
|
|
57
|
setChanged();
|
|
58
|
super.notifyObservers();
|
|
59
|
}
|
|
60
|
|
|
61
|
/**
|
|
62
|
* {@inheritDoc}
|
|
63
|
*
|
|
64
|
* @see java.util.Observable#notifyObservers(java.lang.Object)
|
|
65
|
*/
|
|
66
|
@Override
|
|
67
|
public void notifyObservers(final Object arg) {
|
|
68
|
setChanged();
|
|
69
|
super.notifyObservers(arg);
|
|
70
|
}
|
|
71
|
|
|
72
|
}
|
|
73
|
|
|
74
|
/**
|
|
75
|
* {@inheritDoc}
|
|
76
|
*
|
|
77
|
* @see eu.dnetlib.enabling.resultset.ResultSet#destroy()
|
|
78
|
*/
|
|
79
|
@Override
|
|
80
|
public void destroy() {
|
|
81
|
if (!isDestroyed()) {
|
|
82
|
setDestroyed(true);
|
|
83
|
notifyObservers();
|
|
84
|
deleteObservers();
|
|
85
|
}
|
|
86
|
}
|
|
87
|
|
|
88
|
public void setDestroyed(final boolean destroyed) {
|
|
89
|
this.destroyed = destroyed;
|
|
90
|
}
|
|
91
|
|
|
92
|
@Override
|
|
93
|
public boolean isDestroyed() {
|
|
94
|
return destroyed;
|
|
95
|
}
|
|
96
|
|
|
97
|
/**
|
|
98
|
* {@inheritDoc}
|
|
99
|
*
|
|
100
|
* @see eu.dnetlib.enabling.resultset.ResultSet#isOpen()
|
|
101
|
*/
|
|
102
|
@Override
|
|
103
|
public boolean isOpen() {
|
|
104
|
return open;
|
|
105
|
}
|
|
106
|
|
|
107
|
/**
|
|
108
|
* {@inheritDoc}
|
|
109
|
*
|
|
110
|
* @see eu.dnetlib.enabling.resultset.ResultSet#close()
|
|
111
|
*/
|
|
112
|
@Override
|
|
113
|
public void close() {
|
|
114
|
open = false;
|
|
115
|
}
|
|
116
|
|
|
117
|
public void setOpen(final boolean open) {
|
|
118
|
this.open = open;
|
|
119
|
}
|
|
120
|
|
|
121
|
@Override
|
|
122
|
public void addObserver(final ResultSetRegistry observer) {
|
|
123
|
final DelegationObserver delegate = new DelegationObserver(this, observer);
|
|
124
|
observers.put(observer, delegate);
|
|
125
|
observable.addObserver(delegate);
|
|
126
|
}
|
|
127
|
|
|
128
|
protected void notifyObservers() {
|
|
129
|
observable.notifyObservers();
|
|
130
|
}
|
|
131
|
|
|
132
|
protected void notifyObservers(final Object arg) {
|
|
133
|
observable.notifyObservers(arg);
|
|
134
|
}
|
|
135
|
|
|
136
|
public int countObservers() {
|
|
137
|
return observable.countObservers();
|
|
138
|
}
|
|
139
|
|
|
140
|
public void deleteObserver(final java.util.Observer observer) {
|
|
141
|
observable.deleteObserver(observer);
|
|
142
|
}
|
|
143
|
|
|
144
|
public void deleteObserver(ResultSetRegistry observer) {
|
|
145
|
DelegationObserver delegate = observers.get(observer);
|
|
146
|
if(delegate != null) {
|
|
147
|
observable.deleteObserver(delegate);
|
|
148
|
}
|
|
149
|
}
|
|
150
|
|
|
151
|
public void deleteObservers() {
|
|
152
|
observable.deleteObservers();
|
|
153
|
}
|
|
154
|
|
|
155
|
}
|