    001// Copyright 2010, 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.ioc.internal;
    016
    017import org.apache.tapestry5.commons.ObjectLocator;
    018import org.apache.tapestry5.ioc.internal.util.InternalUtils;
    019
    020public abstract class AbstractConfigurationImpl<T>
    021{
    022    private final Class<T> contributionType;
    023
    024    private final ObjectLocator locator;
    025
    026    public AbstractConfigurationImpl(Class<T> contributionType, ObjectLocator locator)
    027    {
    028        this.contributionType = contributionType;
    029        this.locator = locator;
    030    }
    031
    032    protected T instantiate(Class<? extends T> clazz)
    033    {
    034        assert clazz != null;
    035
    036        // Only attempt to proxy the class if it is the right type for the contribution. Starting
    037        // in 5.3, it is allowed to make contributions of different types (as long as they can be
    038        // coerced to the right type) ... but this means that sometimes, a class is passed that isn't
    039        // assignable to the actual contribution type.
    040
    041        if (contributionType.isInterface() && InternalUtils.isLocalFile(clazz)
    042                && contributionType.isAssignableFrom(clazz))
    043            return locator.proxy(contributionType, clazz);
    044
    045        return locator.autobuild(clazz);
    046    }
    047}