01: // Copyright 2006 The Apache Software Foundation
02: //
03: // Licensed under the Apache License, Version 2.0 (the "License");
04: // you may not use this file except in compliance with the License.
05: // You may obtain a copy of the License at
06: //
07: // http://www.apache.org/licenses/LICENSE-2.0
08: //
09: // Unless required by applicable law or agreed to in writing, software
10: // distributed under the License is distributed on an "AS IS" BASIS,
11: // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12: // See the License for the specific language governing permissions and
13: // limitations under the License.
14:
15: package org.apache.tapestry.annotations;
16:
17: import static java.lang.annotation.ElementType.FIELD;
18: import static java.lang.annotation.RetentionPolicy.RUNTIME;
19:
20: import java.lang.annotation.Documented;
21: import java.lang.annotation.Retention;
22: import java.lang.annotation.Target;
23:
24: /**
25: * Marker annotation placed on fields whose value should be retained past the end of the request.
26: * This is most often associated with fields that are <em>lazily loaded</em>. By marking such
27: * fields with the Retain annotation, the fields will <em>not</em> be discarded at the end of the
28: * request.
29: * <p>
30: * This is quite different from {@link Persist}, because the value that's allowed to be retained is
31: * not stored persistently; it is simply not cleared out. A subsequent request, even from the same
32: * user, may be processed by a different instance of the page where the value is still null.
33: * <p>
34: * This annotation should only be used with lazily-evaluated objects that contain no client-specific
35: * information.
36: */
37: @Target(FIELD)
38: @Retention(RUNTIME)
39: @Documented
40: public @interface Retain {
41:
42: }
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