    001// Copyright 2011 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.plastic;
    016
    017/**
    018 * Defines per-instance context values for a transformed PlasticClass.
    019 */
    020public interface InstanceContext
    021{
    022    /**
    023     * Returns the type of the instance created with this context. This is most often of interest
    024     * to implementations of {@link ComputedValue}.
    025     */
    026    Class<?> getInstanceType();
    027
    028    /**
    029     * Gets an instance context value which is identified by type.
    030     *
    031     * @throws IllegalArgumentException
    032     *             if no such value is available in the context.
    033     */
    034    <T> T get(Class<T> valueType);
    035}