Java tutorial
/** * * Copyright 2010, Lawrence McAlpin. * * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * */ package play.modules.scaffold.strategy; import java.lang.annotation.Annotation; import java.lang.reflect.Field; import java.lang.reflect.ParameterizedType; import java.util.Collection; import java.util.List; import javax.persistence.ManyToMany; import javax.persistence.OneToMany; import javax.persistence.OneToOne; import org.apache.commons.lang.StringUtils; import play.modules.scaffold.form.FormElement; import play.modules.scaffold.form.FormElementType; import play.modules.scaffold.utils.Fields; public class JpaViewScaffoldingStrategy extends DefaultViewScaffoldingStrategy { @Override public FormElement render(Field field) { FormElement defaultValue = super.render(field); if (defaultValue == null) return null; // get the list of annotations List<Class<? extends Annotation>> annotations = Fields.annotations(field); // also get the list of the names of the annotations -- this is a little // redundant, but the reason we do this is because different versions of // Play! support different versions of JPA, and we can't know at compile // time which classes will be available... particularly, we currently // support Play! 1.0 which uses JPA 1 and therefore won't have the // ElementCollection annotation, while Play! 1.1, which uses JPA 2, // does. List<String> annotationNames = Fields.annotationNames(field); if (defaultValue.getType() == FormElementType.TEXT && annotations.contains(javax.persistence.Lob.class)) { return new FormElement(defaultValue, FormElementType.TEXTAREA); } if (annotations.contains(javax.persistence.Id.class)) { return new FormElement(defaultValue, FormElementType.HIDDEN); } else if (annotations.contains(javax.persistence.Embedded.class)) { return new FormElement(defaultValue, FormElementType.EMBEDDED); } else if (annotations.contains(javax.persistence.OneToOne.class)) { OneToOne ann = field.getAnnotation(OneToOne.class); if (!StringUtils.isEmpty(ann.mappedBy())) { return null; } return new FormElement(defaultValue, FormElementType.RELATION); } else if (annotations.contains(javax.persistence.ManyToOne.class)) { return new FormElement(defaultValue, FormElementType.RELATION); } if (Collection.class.isAssignableFrom(field.getType())) { Class<?> parameterizedType = (Class<?>) ((ParameterizedType) field.getGenericType()) .getActualTypeArguments()[0]; if (annotationNames.contains("javax.persistence.ElementCollection") || annotationNames.contains("org.hibernate.annotations.CollectionOfElements")) { return new FormElement(defaultValue, parameterizedType, FormElementType.LIST); } if (annotations.contains(javax.persistence.OneToMany.class)) { OneToMany ann = field.getAnnotation(OneToMany.class); if (!StringUtils.isEmpty(ann.mappedBy())) { return null; } return new FormElement(defaultValue, parameterizedType, FormElementType.RELATION).acceptMultiple(); } if (annotations.contains(javax.persistence.ManyToMany.class)) { ManyToMany ann = field.getAnnotation(ManyToMany.class); if (!StringUtils.isEmpty(ann.mappedBy())) { return null; } return new FormElement(defaultValue, parameterizedType, FormElementType.RELATION).acceptMultiple(); } } return defaultValue; } }