    001    // Copyright 2007, 2009 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.internal.services;
    016
    017    import org.apache.tapestry5.Binding;
    018    import org.apache.tapestry5.internal.bindings.AbstractBinding;
    019    import org.apache.tapestry5.ioc.Location;
    020
    021    /**
    022     * Wraps a {@link StringProvider} as a read-only {@link Binding}.
    023     */
    024    public class AttributeExpansionBinding extends AbstractBinding
    025    {
    026        private final StringProvider provider;
    027
    028        public AttributeExpansionBinding(Location location, StringProvider provider)
    029        {
    030            super(location);
    031
    032            this.provider = provider;
    033        }
    034
    035        public Object get()
    036        {
    037            return provider.provideString();
    038        }
    039
    040        /**
    041         * Returns false. Expansions reference properties that may change arbitrarily.
    042         */
    043        @Override
    044        public boolean isInvariant()
    045        {
    046            return false;
    047        }
    048    }