Entity.java

/**
 *
 * 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.entity;

import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import play.modules.scaffold.Scaffolding;
import play.modules.scaffold.ScaffoldingException;
import play.modules.scaffold.form.FormElement;
import play.modules.scaffold.strategy.ViewScaffoldingStrategy;
import play.modules.scaffold.utils.Classes;
import play.modules.scaffold.utils.Filterable;
import play.modules.scaffold.utils.Strings;

/**
 * Entity holds information related to a domain model entity that we intend to
 * process. For each entity, we generate a controller and basic CRUD view
 * templates.
 * 
 * @author Lawrence McAlpin
 */
public class Entity {
    private String packageName;
    private String name;
    private String controllerName;
    private Class<?> modelType;
    private PersistenceStrategy persistenceStrategy;

    // currently, we only support single field primary keys
    private String idField;
    private Class<?> idClass;

    // form elements that we render in the view
    private List<FormElement> formElements;
    private ViewScaffoldingStrategy scaffoldingStrategy;

    public Entity(Class<?> clazz) {
        this.modelType = clazz;
        this.name = clazz.getSimpleName();
        this.packageName = Classes.getPackageName(clazz);
        Scaffolding scaffolding = clazz.getAnnotation(Scaffolding.class);
        String controllerOverride = null;
        if (scaffolding != null) {
            controllerOverride = scaffolding.controller();
        }
        this.controllerName = controllerOverride != null ? controllerOverride : Strings.pluralize(name);
        this.persistenceStrategy = PersistenceStrategy.forModel(clazz);
        if (persistenceStrategy == null)
            persistenceStrategy = PersistenceStrategy.forEmbeddable(clazz);
        if (persistenceStrategy == null) {
            throw new ScaffoldingException("Could not determine persistence strategy for " + clazz.getName());
        }
        this.scaffoldingStrategy = persistenceStrategy.getViewScaffoldingStrategy();
        this.formElements = new ArrayList<FormElement>();

        List<Field> fields = publicFields(clazz);
        for (Field field : fields) {
            if (persistenceStrategy.isId(field)) {
                idField = field.getName();
                idClass = field.getType();
            }
            addFormElement(field);
        }
    }

    public static List<Field> publicFields(Class<?> clazz) {
        final List<Field> fields = Classes.publicFields(clazz);
        Filterable.remove(fields, new Filterable<Field>() {

            @Override
            public boolean filter(Field input) {
                int modifiers = input.getModifiers();
                if (Modifier.isTransient(modifiers) || Modifier.isStatic(modifiers))
                    return true;
                return false;
            }

        });
        return fields;
    }

    private void addFormElement(Field field) {
        FormElement formElement = scaffoldingStrategy.render(field);
        if (formElement != null) {
            formElements.add(formElement);
        }
    }

    public List<FormElement> getFormElements() {
        return formElements;
    }

    public String getIdField() {
        return idField;
    }

    public Class<?> getModelType() {
        return modelType;
    }

    public Class<?> getIdClass() {
        return idClass;
    }

    public String getControllerName() {
        return controllerName;
    }

    public String getName() {
        return name;
    }

    public String getPackageName() {
        return packageName;
    }

    public PersistenceStrategy getPersistenceStrategy() {
        return persistenceStrategy;
    }

    public ViewScaffoldingStrategy getScaffoldingStrategy() {
        return scaffoldingStrategy;
    }

    public String getPackage() {
        return packageName;
    }

    public boolean getUsesPlayModelSupport() {
        return persistenceStrategy.getUsesPlayModelSupport();
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        result = prime * result + ((packageName == null) ? 0 : packageName.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Entity other = (Entity) obj;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        if (packageName == null) {
            if (other.packageName != null)
                return false;
        } else if (!packageName.equals(other.packageName))
            return false;
        return true;
    }

    @Override
    public String toString() {
        return "Entity [packageName=" + packageName + ", name=" + name + "]";
    }

    private static Map<String, Entity> ENTITY_CACHE = new HashMap<String, Entity>();

    public static Entity from(Class<?> clazz) {
        Entity entity = ENTITY_CACHE.get(clazz.getName());
        if (entity == null) {
            entity = new Entity(clazz);
            ENTITY_CACHE.put(clazz.getName(), entity);
        }
        return entity;
    }
}