001    // Copyright 2005 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.tapestry.enhance;
016    
017    import java.lang.reflect.Modifier;
018    import java.util.Iterator;
019    
020    import org.apache.hivemind.ApplicationRuntimeException;
021    import org.apache.hivemind.ErrorLog;
022    import org.apache.hivemind.Location;
023    import org.apache.hivemind.service.MethodSignature;
024    import org.apache.hivemind.util.Defense;
025    import org.apache.tapestry.IAsset;
026    import org.apache.tapestry.spec.IAssetSpecification;
027    import org.apache.tapestry.spec.IComponentSpecification;
028    
029    /**
030     * Injects assets as component properties.
031     * 
032     * @author Howard M. Lewis Ship
033     * @since 4.0
034     */
035    public class InjectAssetWorker implements EnhancementWorker
036    {
037        private ErrorLog _errorLog;
038    
039        public void performEnhancement(EnhancementOperation op, IComponentSpecification spec)
040        {
041            Iterator i = spec.getAssetNames().iterator();
042            while (i.hasNext())
043            {
044                String name = (String) i.next();
045    
046                IAssetSpecification as = spec.getAsset(name);
047    
048                String propertyName = as.getPropertyName();
049    
050                if (propertyName != null)
051                {
052                    try
053                    {
054                        injectAsset(op, name, propertyName, as.getLocation());
055                    }
056                    catch (Exception ex)
057                    {
058                        _errorLog.error(EnhanceMessages.errorAddingProperty(propertyName, op
059                                .getBaseClass(), ex), as.getLocation(), ex);
060                    }
061                }
062            }
063        }
064    
065        public void injectAsset(EnhancementOperation op, String assetName, String propertyName,
066                Location location)
067        {
068            Defense.notNull(op, "op");
069            Defense.notNull(assetName, "assetName");
070            Defense.notNull(propertyName, "propertyName");
071    
072            Class propertyType = EnhanceUtils.extractPropertyType(op, propertyName, null);
073    
074            op.claimReadonlyProperty(propertyName);
075    
076            if (!propertyType.isAssignableFrom(IAsset.class))
077                throw new ApplicationRuntimeException(EnhanceMessages.incompatiblePropertyType(
078                        propertyName,
079                        propertyType,
080                        IAsset.class));
081    
082            String methodName = op.getAccessorMethodName(propertyName);
083    
084            MethodSignature sig = new MethodSignature(propertyType, methodName, null, null);
085    
086            String code = "return getAsset(\"" + assetName + "\");";
087    
088            op.addMethod(Modifier.PUBLIC, sig, code, location);
089        }
090    
091        public void setErrorLog(ErrorLog errorLog)
092        {
093            _errorLog = errorLog;
094        }
095    }