    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.ioc.internal;
    016
    017import org.apache.tapestry5.ioc.ObjectLocator;
    018import org.apache.tapestry5.ioc.services.TypeCoercer;
    019
    020/**
    021 * A proxy for the {@link TypeCoercer}
    022 *
    023 * @since 5.3
    024 */
    025public final class TypeCoercerProxyImpl implements TypeCoercerProxy
    026{
    027    private final ObjectLocator locator;
    028
    029    private TypeCoercer delegate;
    030
    031    public TypeCoercerProxyImpl(ObjectLocator locator)
    032    {
    033        this.locator = locator;
    034    }
    035
    036    private TypeCoercer delegate()
    037    {
    038        if (delegate == null)
    039            delegate = locator.getService(TypeCoercer.class);
    040
    041        return delegate;
    042    }
    043
    044    @Override
    045    public <S, T> T coerce(S input, Class<T> targetType)
    046    {
    047        if (targetType.isInstance(input))
    048            return targetType.cast(input);
    049
    050        return delegate().coerce(input, targetType);
    051    }
    052
    053}