/*
    * Copyright 2002-2014 the original author or authors.
    *
    * 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.springframework.expression.spel.ast;
  
  import org.springframework.expression.AccessException;
  import org.springframework.expression.BeanResolver;
  import org.springframework.expression.EvaluationException;
  import org.springframework.expression.TypedValue;
  import org.springframework.expression.spel.ExpressionState;
  import org.springframework.expression.spel.SpelEvaluationException;
  import org.springframework.expression.spel.SpelMessage;
  
  /**
   * Represents a bean reference to a type, for example "@foo" or "@'foo.bar'"
   *
   * @author Andy Clement
   */
  public class BeanReference extends SpelNodeImpl {
  
  	private final String beanName;
  
  
  	public BeanReference(int pos,String beanName) {
  		super(pos);
  		this.beanName = beanName;
  	}
  
  
  	@Override
  	public TypedValue getValueInternal(ExpressionState state) throws EvaluationException {
  		BeanResolver beanResolver = state.getEvaluationContext().getBeanResolver();
  		if (beanResolver == null) {
  			throw new SpelEvaluationException(
  					getStartPosition(), SpelMessage.NO_BEAN_RESOLVER_REGISTERED, this.beanName);
  		}
  
  		try {
  			return new TypedValue(beanResolver.resolve(state.getEvaluationContext(), this.beanName));
  		}
  		catch (AccessException ex) {
  			throw new SpelEvaluationException(getStartPosition(), ex, SpelMessage.EXCEPTION_DURING_BEAN_RESOLUTION,
  				this.beanName, ex.getMessage());
  		}
  	}
  
  	@Override
  	public String toStringAST() {
  		StringBuilder sb = new StringBuilder("@");
  		if (!this.beanName.contains(".")) {
  			sb.append(this.beanName);
  		}
  		else {
  			sb.append("'").append(this.beanName).append("'");
  		}
  		return sb.toString();
  	}
  
  }