/*
    * 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.EvaluationException;
  import org.springframework.expression.TypedValue;
  import org.springframework.expression.spel.ExpressionState;
  
  /**
   * Represents a dot separated sequence of strings that indicate a package qualified type
   * reference.
   *
   * <p>Example: "java.lang.String" as in the expression "new java.lang.String('hello')"
   *
   * @author Andy Clement
   * @since 3.0
   */
  public class QualifiedIdentifier extends SpelNodeImpl {
  
  	// TODO safe to cache? dont think so
  	private TypedValue value;
  
  
  	public QualifiedIdentifier(int pos, SpelNodeImpl... operands) {
  		super(pos, operands);
  	}
  
  
  	@Override
  	public TypedValue getValueInternal(ExpressionState state) throws EvaluationException {
  		// Cache the concatenation of child identifiers
  		if (this.value == null) {
  			StringBuilder sb = new StringBuilder();
  			for (int i = 0; i < getChildCount(); i++) {
  				Object value = this.children[i].getValueInternal(state).getValue();
  				if (i > 0 && !value.toString().startsWith("$")) {
  					sb.append(".");
  				}
  				sb.append(value);
  			}
  			this.value = new TypedValue(sb.toString());
  		}
  		return this.value;
  	}
  
  	@Override
  	public String toStringAST() {
  		StringBuilder sb = new StringBuilder();
  		if (this.value != null) {
  			sb.append(this.value.getValue());
  		}
  		else {
  			for (int i = 0; i < getChildCount(); i++) {
  				if (i > 0) {
  					sb.append(".");
  				}
  				sb.append(getChild(i).toStringAST());
  			}
  		}
  		return sb.toString();
  	}
  
  }