    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
    015    package org.apache.tapestry5.ioc.internal;
    016
    017    import org.apache.tapestry5.ioc.ObjectLocator;
    018    import org.apache.tapestry5.ioc.services.TypeCoercer;
    019
    020    /**
    021     * A proxy for the {@link TypeCoercer}
    022     *
    023     * @since 5.3
    024     */
    025    public 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        public <S, T> T coerce(S input, Class<T> targetType)
    045        {
    046            if (targetType.isInstance(input))
    047                return targetType.cast(input);
    048
    049            return delegate().coerce(input, targetType);
    050        }
    051
    052    }