    001    // Copyright 2006, 2008, 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.bindings;
    016
    017    import org.apache.tapestry5.PropertyConduit;
    018    import org.apache.tapestry5.internal.TapestryInternalUtils;
    019    import org.apache.tapestry5.internal.services.Invariant;
    020    import org.apache.tapestry5.ioc.Location;
    021    import org.apache.tapestry5.ioc.internal.util.TapestryException;
    022
    023    import java.lang.annotation.Annotation;
    024
    025    /**
    026     * Base class for bindings created by the {@link org.apache.tapestry5.internal.bindings.PropBindingFactory}. A subclass
    027     * of this is created at runtime.
    028     */
    029    public class PropBinding extends AbstractBinding implements InternalPropBinding
    030    {
    031        private final Object root;
    032
    033        private final PropertyConduit conduit;
    034
    035        private final String toString;
    036
    037        private boolean invariant;
    038
    039        private final String expression;
    040
    041        public PropBinding(final Location location, final Object root, final PropertyConduit conduit, final String expression, final String toString)
    042        {
    043            super(location);
    044
    045            this.root = root;
    046            this.conduit = conduit;
    047            this.expression = expression;
    048            this.toString = toString;
    049
    050            invariant = conduit.getAnnotation(Invariant.class) != null;
    051        }
    052
    053        /**
    054         * The default implementation of get() will throw a TapestryException (binding is write only). The fabricated
    055         * subclass <em>may</em> override this method (as well as set()).
    056         */
    057        public Object get()
    058        {
    059            try
    060            {
    061                return conduit.get(root);
    062            }
    063            catch (Exception ex)
    064            {
    065                throw new TapestryException(ex.getMessage(), getLocation(), ex);
    066            }
    067        }
    068
    069        @Override
    070        public void set(Object value)
    071        {
    072            try
    073            {
    074                conduit.set(root, value);
    075            }
    076            catch (Exception ex)
    077            {
    078                throw new TapestryException(ex.getMessage(), getLocation(), ex);
    079            }
    080        }
    081
    082        @Override
    083        public String toString()
    084        {
    085            return toString;
    086        }
    087
    088        /**
    089         * Almost always returns false, unless the conduit provides the {@link org.apache.tapestry5.internal.services.Invariant}
    090         * annotation.
    091         */
    092        @Override
    093        public boolean isInvariant()
    094        {
    095            return invariant;
    096        }
    097
    098        @Override
    099        public Class getBindingType()
    100        {
    101            return conduit.getPropertyType();
    102        }
    103
    104        @Override
    105        public <T extends Annotation> T getAnnotation(Class<T> annotationClass)
    106        {
    107            return conduit.getAnnotation(annotationClass);
    108        }
    109
    110            public String getPropertyName()
    111            {
    112                    return TapestryInternalUtils.toInternalPropertyConduit(conduit).getPropertyName();
    113            }
    114
    115        public String getExpression()
    116        {
    117            return expression;
    118        }
    119
    120    }