01: // Copyright 2007 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.services;
16:
17: import org.apache.tapestry.annotations.Environmental;
18: import org.apache.tapestry.ioc.services.PropertyShadowBuilder;
19:
20: /**
21: * Much like {@link PropertyShadowBuilder}, except that instead of accessing a property of some
22: * other service, it accesses a value from within the {@link Environment} service. This is useful
23: * for defining a new service that can be injected into other services (whereas the
24: * {@link Environmental} annotation may only be used within component classes).
25: */
26: public interface EnvironmentalShadowBuilder {
27: /**
28: * Returns a proxy that delegates all methods to an object obtained from
29: * {@link Environment#peekRequired(Class)}. Note that at the time this method is invoked, the
30: * Environment service may still be virtual, and will often not yet have been loaded with
31: * values, and that's OK, the resolution is deferred to the instant a method is invoked.
32: *
33: * @param <T>
34: * @param serviceType
35: * the service type, which is used to obtained the delegate instance
36: * @return a proxy to the service
37: */
38: <T> T build(Class<T> serviceType);
39: }
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