/*

  * Copyright 2004-2011 the Seasar Foundation and the Others.

  *

  * 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 org.seasar.teeda.core.el.impl;

 import java.util.Collections;

 import java.util.HashMap;

 import java.util.Map;

 import javax.faces.application.Application;

 import javax.faces.component.StateHolder;

 import javax.faces.context.FacesContext;

 import javax.faces.el.ValueBinding;

 import org.seasar.framework.exception.EmptyRuntimeException;

 import org.seasar.framework.util.StringUtil;

 import org.seasar.teeda.core.el.ELParser;

 import org.seasar.teeda.core.el.ValueBindingFactory;

 /**

  * @author shot

  */

 public class ValueBindingFactoryImpl implements ValueBindingFactory {

     private Map cache = Collections.synchronizedMap(new HashMap());

     private ELParser parser;

     public ValueBindingFactoryImpl() {

         this.parser = ELParserFactory.createELParser();

     }

     public void setELParser(ELParser parser) {

         this.parser = parser;

     }

     public ELParser getELParser() {

         return parser;

     }

     public ValueBinding createValueBinding(Application application,

             String expression) {

         if (StringUtil.isEmpty(expression)) {

             throw new EmptyRuntimeException("Expression string");

         }

         if (application == null) {

             throw new EmptyRuntimeException("Application");

         }

         ValueBinding vb = getValueBindingFromCache(application, expression);

         if (vb != null) {

             return vb;

         }

         vb = new ValueBindingImpl(application, expression, getELParser());

         cache.put(expression, vb);

         return vb;

     }

     public void clearCache() {

         cache.clear();

     }

     protected ValueBinding getRestoredValueBinding(StateHolder holder,

             String expression) {

         FacesContext context = FacesContext.getCurrentInstance();

         holder

                 .restoreState(context,

                         new Object[] { expression, getELParser() });

         return (ValueBinding) holder;

     }

     protected ValueBinding getValueBindingFromCache(Application application,

             String expression) {

         ValueBinding vb = (ValueBinding) cache.get(expression);

         if (vb != null && vb instanceof StateHolder) {

             vb = getRestoredValueBinding((StateHolder) vb, expression);

         }

         return vb;

     }

 }