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
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
/* Copyright (c) 2006-2012 by OpenLayers Contributors (see authors.txt for
* full list of contributors). Published under the Clear BSD license.
* See http://svn.openlayers.org/trunk/openlayers/license.txt for the
* full text of the license. */
/**
* @requires OpenLayers/Strategy.js
*/
/**
* Class: OpenLayers.Strategy.Fixed
* A simple strategy that requests features once and never requests new data.
*
* Inherits from:
* - <OpenLayers.Strategy>
*/
OpenLayers.Strategy.Fixed = OpenLayers.Class(OpenLayers.Strategy, {
/**
* APIProperty: preload
* {Boolean} Load data before layer made visible. Enabling this may result
* in considerable overhead if your application loads many data layers
* that are not visible by default. Default is false.
*/
preload: false,
/**
* Constructor: OpenLayers.Strategy.Fixed
* Create a new Fixed strategy.
*
* Parameters:
* options - {Object} Optional object whose properties will be set on the
* instance.
*/
/**
* Method: activate
* Activate the strategy: load data or add listener to load when visible
*
* Returns:
* {Boolean} True if the strategy was successfully activated or false if
* the strategy was already active.
*/
activate: function() {
if(OpenLayers.Strategy.prototype.activate.apply(this, arguments)) {
this.layer.events.on({
"refresh": this.load,
scope: this
});
if(this.layer.visibility == true || this.preload) {
this.load();
} else {
this.layer.events.on({
"visibilitychanged": this.load,
scope: this
});
}
return true;
}
return false;
},
/**
* Method: deactivate
* Deactivate the strategy. Undo what is done in <activate>.
*
* Returns:
* {Boolean} The strategy was successfully deactivated.
*/
deactivate: function() {
var deactivated = OpenLayers.Strategy.prototype.deactivate.call(this);
if(deactivated) {
this.layer.events.un({
"refresh": this.load,
"visibilitychanged": this.load,
scope: this
});
}
return deactivated;
},
/**
* Method: load
* Tells protocol to load data and unhooks the visibilitychanged event
*
* Parameters:
* options - {Object} options to pass to protocol read.
*/
load: function(options) {
var layer = this.layer;
layer.events.triggerEvent("loadstart");
layer.protocol.read(OpenLayers.Util.applyDefaults({
callback: OpenLayers.Function.bind(this.merge, this,
layer.map.getProjectionObject()),
filter: layer.filter
}, options));
layer.events.un({
"visibilitychanged": this.load,
scope: this
});
},
/**
* Method: merge
* Add all features to the layer.
*
* Parameters:
* mapProjection - {<OpenLayers.Projection>} the map projection
* resp - {Object} options to pass to protocol read.
*/
merge: function(mapProjection, resp) {
var layer = this.layer;
layer.destroyFeatures();
var features = resp.features;
if (features && features.length > 0) {
if(!mapProjection.equals(layer.projection)) {
var geom;
for(var i=0, len=features.length; i<len; ++i) {
geom = features[i].geometry;
if(geom) {
geom.transform(layer.projection, mapProjection);
}
}
}
layer.addFeatures(features);
}
layer.events.triggerEvent("loadend");
},
CLASS_NAME: "OpenLayers.Strategy.Fixed"
});
|