| // Copyright 2007, 2008, 2009 The Apache Software Foundation |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package org.apache.tapestry5.services; |
| |
| import org.apache.tapestry5.PropertyConduit; |
| |
| /** |
| * A source for {@link org.apache.tapestry5.PropertyConduit}s, which can be thought of as a compiled property path |
| * expression. PropertyConduits are the basis of the "prop:" binding factory, thus this service defines the expression |
| * format used by the {@link org.apache.tapestry5.internal.bindings.PropBindingFactory}. |
| */ |
| public interface PropertyConduitSource |
| { |
| /** |
| * Returns a property conduit instance for the given expression. PropertyConduitSource caches the conduits it |
| * returns, so despite the name, this method does not always create a <em>new</em> conduit. The cache is cleared if |
| * a change to component classes is observed. |
| * <p/> |
| * Callers of this method should observe notifications from the {@link org.apache.tapestry5.services.InvalidationEventHub} |
| * for {@link org.apache.tapestry5.services.ComponentClasses} and discard any aquired conduits; failure to do so |
| * will create memory leaks whenever component classes change (the conduits will keep references to the old classes |
| * and classloaders). |
| * |
| * @param rootType the type of the root object to which the expression is applied |
| * @param expression expression to be evaluated on instances of the root class |
| * @return RuntimeException if the expression is invalid (poorly formed, references non-existent properties, etc.) |
| */ |
| PropertyConduit create(Class rootType, String expression); |
| } |
