001// Copyright 2010, 2011, 2012 The Apache Software Foundation 002// 003// Licensed under the Apache License, Version 2.0 (the "License"); 004// you may not use this file except in compliance with the License. 005// You may obtain a copy of the License at 006// 007// http://www.apache.org/licenses/LICENSE-2.0 008// 009// Unless required by applicable law or agreed to in writing, software 010// distributed under the License is distributed on an "AS IS" BASIS, 011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 012// See the License for the specific language governing permissions and 013// limitations under the License. 014 015package org.apache.tapestry5.internal.transform; 016 017import org.apache.tapestry5.Binding; 018import org.apache.tapestry5.annotations.Parameter; 019import org.apache.tapestry5.internal.InternalComponentResources; 020import org.apache.tapestry5.ioc.services.TypeCoercer; 021import org.apache.tapestry5.plastic.FieldConduit; 022 023/** 024 * A facade around {@link Binding} and {@link InternalComponentResources} that is used to instrument 025 * fields with the {@link Parameter} annotation. Extends {@link FieldConduit} so that 026 * the get() method implicitly coerces the value to the field's type. 027 * <p/> 028 * {@link #get(Object, org.apache.tapestry5.plastic.InstanceContext)} will read from the underlying {@link Binding} and used the {@link TypeCoercer} coerce the value to the 029 * parameter field's type. get() also includes a null value check (as per {@link Parameter#allowNull()}. 030 * <p/> 031 * {@link #set(Object, org.apache.tapestry5.plastic.InstanceContext, Object)} pushes the value into the binding. 032 * 033 * @since 5.2.0 034 */ 035public interface ParameterConduit extends FieldConduit<Object> 036{ 037 /** 038 * Determines if the parameter is actually bound. 039 * 040 * @return true if bound 041 */ 042 boolean isBound(); 043 044 /** 045 * Resets the conduit, clearing any <em>temporarily</em> cached data (from a non-invariant {@link Binding}). 046 */ 047 void reset(); 048}