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      1 /*
      2  * Licensed to the Apache Software Foundation (ASF) under one
      3  * or more contributor license agreements. See the NOTICE file
      4  * distributed with this work for additional information
      5  * regarding copyright ownership. The ASF licenses this file
      6  * to you under the Apache License, Version 2.0 (the  "License");
      7  * you may not use this file except in compliance with the License.
      8  * You may obtain a copy of the License at
      9  *
     10  *     http://www.apache.org/licenses/LICENSE-2.0
     11  *
     12  * Unless required by applicable law or agreed to in writing, software
     13  * distributed under the License is distributed on an "AS IS" BASIS,
     14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     15  * See the License for the specific language governing permissions and
     16  * limitations under the License.
     17  */
     18 /*
     19  * $Id: StringBufferPool.java 468655 2006-10-28 07:12:06Z minchau $
     20  */
     21 package org.apache.xml.utils;
     22 
     23 /**
     24  * This class pools string buffers, since they are reused so often.
     25  * String buffers are good candidates for pooling, because of
     26  * their supporting character arrays.
     27  * @xsl.usage internal
     28  */
     29 public class StringBufferPool
     30 {
     31 
     32   /** The global pool of string buffers.   */
     33   private static ObjectPool m_stringBufPool =
     34     new ObjectPool(org.apache.xml.utils.FastStringBuffer.class);
     35 
     36   /**
     37    * Get the first free instance of a string buffer, or create one
     38    * if there are no free instances.
     39    *
     40    * @return A string buffer ready for use.
     41    */
     42   public synchronized static FastStringBuffer get()
     43   {
     44     return (FastStringBuffer) m_stringBufPool.getInstance();
     45   }
     46 
     47   /**
     48    * Return a string buffer back to the pool.
     49    *
     50    * @param sb Must be a non-null reference to a string buffer.
     51    */
     52   public synchronized static void free(FastStringBuffer sb)
     53   {
     54     // Since this isn't synchronized, setLength must be
     55     // done before the instance is freed.
     56     // Fix attributed to Peter Speck <speck (at) ruc.dk>.
     57     sb.setLength(0);
     58     m_stringBufPool.freeInstance(sb);
     59   }
     60 }
     61