| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.apache.freemarker.core; |
| |
| /** Don't use this; used internally by FreeMarker, might change without notice. */ |
| public abstract class _DelayedConversionToString { |
| |
| private static final String NOT_SET = new String(); |
| |
| private Object object; |
| private volatile String stringValue = NOT_SET; |
| |
| public _DelayedConversionToString(Object object) { |
| this.object = object; |
| } |
| |
| @Override |
| public String toString() { |
| String stringValue = this.stringValue; |
| if (stringValue == NOT_SET) { |
| synchronized (this) { |
| stringValue = this.stringValue; |
| if (stringValue == NOT_SET) { |
| stringValue = doConversion(object); |
| this.stringValue = stringValue; |
| object = null; |
| } |
| } |
| } |
| return stringValue; |
| } |
| |
| protected abstract String doConversion(Object obj); |
| |
| } |