/**

  * Copyright (C) 2006 Philipp Mpalampanis

  *

  * License: MPL 1.1/GPL 2.0/LGPL 2.1

  *

  * The contents of this file are subject to the Mozilla Public License Version

  * 1.1 (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.mozilla.org/MPL/

  *

  * Software distributed under the License is distributed on an "AS IS" basis,

  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License

  * for the specific language governing rights and limitations under the

  * License.

  *

  * Alternatively, the contents of this file may be used under the terms of

  * either the GNU General Public License Version 2 or later (the "GPL"), or

  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),

  * in which case the provisions of the GPL or the LGPL are applicable instead

  * of those above. If you wish to allow use of your version of this file only

  * under the terms of either the GPL or the LGPL, and not to allow others to

  * use your version of this file under the terms of the MPL, indicate your

  * decision by deleting the provisions above and replace them with the notice

  * and other provisions required by the GPL or the LGPL. If you do not delete

  * the provisions above, a recipient may use your version of this file under

  * the terms of any one of the MPL, the GPL or the LGPL.

  */

 package net.sf.echobinding.binding;

 import java.beans.PropertyChangeListener;

 import java.beans.PropertyChangeSupport;

 import java.io.Serializable;

 import java.lang.reflect.Method;

 import java.util.HashMap;

 import java.util.Map.Entry;

 import net.sf.echobinding.model.PresentationModel;

 import net.sf.echobinding.validation.ValidationHandler;

 import net.sf.echobinding.validation.ValidationReport;

 import ognl.Ognl;

 import ognl.OgnlContext;

 import org.apache.log4j.Logger;

 /**

  * 

  */

 public class OgnlBindingContext extends AbstractBindingContext {

         private static final long serialVersionUID = -3799783525654201978L;

         /**

          * The OGNL namespace/prefix used to access the presentation model. 

          */

         public static final String OGNL_NAMESPACE_PMOD = "pm";

         @SuppressWarnings("unused")

         private final Logger _logger = Logger.getLogger(OgnlBindingContext.class);

         private Object _model;

         private OgnlContext _ognlContext = new OgnlContext();

         private HashMap<String, Object> _contextMap = new HashMap<String, Object>();

         private ValidationHandler _validationHandler;

         /**

          * Creates a new OgnlBindingContext.

          * 

          * @param bean The bean

          *

          */

         public OgnlBindingContext(Object bean) {

                 this();

                 setModel(bean);

         }

         /**

          * Creates a new OgnlBindingContext.

          *

          */

         public OgnlBindingContext() {

                 super();

         }

         public BindingContext add(String id, PropertyAdapter adapter) {

                 if (!(adapter instanceof OgnlPropertyAdapter))

                         throw new ClassCastException("Adapter has to be of type OgnlPropertyAdapter!");

                 super.add(id, adapter);

                 return this;

         }

         public Object getValue(String id) throws BindingException {

                 OgnlPropertyAdapter adapter = getAdapter(id);

                 Object value = (_ognlContext == null) ? adapter.getValue(_model)

                                 : adapter.getValue(_ognlContext, _model);

                 return value;

         }

         /*

          * (non-Javadoc)

          * 

          * @see echobinding.BindingContext#setValue(java.lang.String,

          *      java.lang.Object)

          */

         public void setValue(String id, Object value) throws BindingException {

                 OgnlPropertyAdapter adapter = getAdapter(id);

                 Object oldValue = this.getValue(id);

                 if (_ognlContext == null)

                         adapter.setValue( _model, value );

                 else

                         adapter.setValue( _ognlContext, _model, value );

                 firePropertyChange(id, oldValue, value);

         }

         /*

          * (non-Javadoc)

          * 

          * @see echobinding.BindingContext#isValid(java.lang.String,

          *      java.lang.Object)

          */

         @SuppressWarnings("unchecked")

         public ValidationReport validate(String id, Object value) {

                 Object bean = getModel();

                 OgnlPropertyAdapter adapter = getAdapter(id);

                 String ognlNameSpace = adapter.getOgnlContextName();

                 if(ognlNameSpace != null && getOgnlContext() != null) {

                         bean = getOgnlContext().get( ognlNameSpace );

                 }

                 return adapter.validate(bean, value);

         }

         /*

          * (non-Javadoc)

          * 

          * @see echobinding.BindingContext#getModel()

          */

         public Object getModel() {

                 return _model;

         }

         /*

          * (non-Javadoc)

          * 

          * @see echobinding.BindingContext#setModel(java.lang.Object)

          */

         public OgnlBindingContext setModel(Object bean) {

                 _model = bean;

                 registerSource( bean );

                 return this;

         }

         @Override

         public void setPresentationModel(PresentationModel presentationModel) {

                 super.setPresentationModel( presentationModel );

                 addModel( OGNL_NAMESPACE_PMOD, presentationModel );

         }

         /**

          * Tries to add this BindingContext as a property change listener to the

          * source bean.

          * 

          * @param contextRoot

          */

         private void registerSource(Object contextRoot) {

                 if(contextRoot==null)

                         return;

                 if ( contextRoot instanceof PropertyChangeSupport ) {

                         PropertyChangeSupport propertyChangeSupport = (PropertyChangeSupport) contextRoot;

                         propertyChangeSupport.addPropertyChangeListener(this);

                 } 

                 else {

                         // check if class provides the addPropertyListener method

                         Class contextClass = contextRoot.getClass();

                         Class[] parameterTypes = new Class[] {PropertyChangeListener.class};

                         Object[] arguments = new Object[] {this};

                         Method addPropertyChangeListenerMethod;

                         try {

                                 addPropertyChangeListenerMethod = contextClass.getMethod("addPropertyChangeListener", parameterTypes);

                                 addPropertyChangeListenerMethod.invoke(contextRoot, arguments);

                         } catch (Exception e) {

                                 // ignore

                         }

                 }

         }

         /**

          * Adds a bean to the OgnlContext. Additional beans can be referenced with

          * "#contextName.property" in an OGNL expression.

          * 

          * @param contextName

          * @param bean

          * @return

          */

         public OgnlBindingContext addModel(String contextName, Object bean) {

                 if (_ognlContext == null)

                         _ognlContext = (OgnlContext) Ognl

                                         .createDefaultContext( _model );

                 _ognlContext.put(contextName, bean);

                 _contextMap.put(contextName, bean);

                 return this;

         }

         public BindingContext createChild() {

                 OgnlBindingContext childContext = new OgnlBindingContext();

                 for (Entry<String, PropertyAdapter> entry : _adapters.entrySet()) {

                         PropertyAdapter clonedAdapter = entry.getValue().newInstance();

                         childContext.add(entry.getKey(), clonedAdapter);

                 }

                 childContext.setContextMap(getContextMap());

                 childContext.setParent(this);

                 if(getPresentationModel()!=null)

                         childContext.setPresentationModel(getPresentationModel().cloneInstance());

                 addChild(childContext);

                 childContext.setModel(getModel());

                 return childContext;

         }

         /**

          * Returns the context map. 

          * 

          * @return

          */

         public HashMap<String, Object> getContextMap() {

                 return _contextMap;

         }

         protected OgnlContext getOgnlContext() {

                 return _ognlContext;

         }

         /**

          * Sets the context map. The context map is a list of additional source

          * objects which are used for binding. 

          * 

          * @param contextMap

          */

         public void setContextMap(HashMap<String, Object> contextMap) {

                 _contextMap = contextMap;

                 if (contextMap != null) {

                         for (Entry<String, Object> entry : contextMap.entrySet()) {

                                 _ognlContext.put(entry.getKey(), entry.getValue());

                         }

                 }

         }

         /* (non-Javadoc)

          * @see echobinding.binding.BindingContext#getValidationhandler(java.lang.String)

          */

         public ValidationHandler getValidationHandler(String id) {

                 ValidationHandler handler = getAdapter(id).getValidationHandler();

                 return (handler==null) ? getValidationHandler() : handler;

         }

         /* (non-Javadoc)

          * @see echobinding.binding.BindingContext#setValidationHandler(echobinding.validation.ValidationHandler)

          */

         public BindingContext setValidationHandler(ValidationHandler handler) {

                 _validationHandler = handler;

                 return this;

         }

         /* (non-Javadoc)

          * @see echobinding.binding.BindingContext#getValidationHandler()

          */

         public ValidationHandler getValidationHandler() {

                 return _validationHandler;

         }

         /* (non-Javadoc)

          * @see echobinding.binding.BindingContext#isDirty(java.lang.String, java.lang.Object)

          */

         public boolean isDirty(String id, Object value) throws BindingException {

                 Object oldValue = getValue( id );

                 if(oldValue==null) {

                         if(value==null)

                                 return false;

                         return true;

                 }

                 return ! oldValue.equals(value);

         }

         /**

          * Returns the <code>PropertyAdapter</code> for the given id. If no adapter for

          * this id exists, a new adapter will be lazely generated using the id as

          * binding expression. The newly generated adapter will added to he list of

          * adapters.

          * 

          * @param id

          * @return

          */

         public OgnlPropertyAdapter getAdapter(String id) {

                 OgnlPropertyAdapter adapter = (OgnlPropertyAdapter) _adapters.get(id);

                 if (adapter == null) {

                         // create a new adapter

                         adapter = new OgnlPropertyAdapter(id);

                         this.add(id, adapter);

                 }

                 return adapter;

         }

 }