content: /*
   * Template.java February 2001
   *
   * Copyright (C) 2001, Niall Gallagher <niallg@users.sf.net>
   *
   * 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 com.aliyun.odps.simpleframework.xml.core;
  
  /** 
   * This is primarily used to replace the <code>StringBuffer</code> 
   * class, as a way for the <code>TemplateEngine</code> to store the 
   * data for a specific region within the parse data that constitutes 
   * a desired value. The methods are not synchronized so it enables 
   * the characters to be taken quicker than the string buffer class.
   *
   * @author Niall Gallagher
   */
  class Template {      
  
     /** 
      * This is used to quicken <code>toString</code>.
      */
     protected String cache;
  
     /** 
      * The characters that this buffer has accumulated.
      */
     protected char[] buf;
  
     /** 
      * This is the number of characters this has stored.
      */
     protected int count;
     
     /** 
      * Constructor for <code>Template</code>. The default 
      * <code>Template</code> stores 16 characters before a
      * <code>resize</code> is needed to append extra characters. 
      */
     public Template(){
        this(16);
     }
     
     /** 
      * This creates a <code>Template</code> with a specific 
      * default size. The buffer will be created the with the 
      * length specified. The <code>Template</code> can grow 
      * to accomodate a collection of characters larger the the 
      * size spacified.
      *
      * @param size initial size of this <code>Template</code>
      */
     public Template(int size){
        this.buf = new char[size];
     }
     
     /** 
      * This will add a <code>char</code> to the end of the buffer.
      * The buffer will not overflow with repeated uses of the 
      * <code>append</code>, it uses an <code>ensureCapacity</code>
      * method which will allow the buffer to dynamically grow in 
      * size to accomodate more characters.
      *
      * @param c the <code>char</code> to be appended
      */
     public void append(char c){
        ensureCapacity(count+ 1);
        buf[count++] = c;
     }
  
     /** 
      * This will add a <code>String</code> to the end of the buffer.
      * The buffer will not overflow with repeated uses of the 
      * <code>append</code>, it uses an <code>ensureCapacity</code> 
      * method which will allow the buffer to dynamically grow in 
      * size to accomodate large <code>String</code> objects.
      *
      * @param str the <code>String</code> to be appended to this
      */  
     public void append(String str){
        ensureCapacity(count+ str.length());
        str.getChars(0,str.length(),buf,count);
        count += str.length();
     }
  
     /** 
      * This will add a <code>Template</code> to the end of this.
      * The buffer will not overflow with repeated uses of the 
      * <code>append</code>, it uses an <code>ensureCapacity</code> 
      * method which will allow the buffer to dynamically grow in 
      * size to accomodate large <code>Template</code> objects.
      *
      * @param text the <code>Template</code> to be appended 
      */  
     public void append(Template text){
        append(text.buf, 0, text.count);           
     }
     
     /** 
      * This will add a <code>char</code> to the end of the buffer.
      * The buffer will not overflow with repeated uses of the 
      * <code>append</code>, it uses an <code>ensureCapacity</code> 
      * method which will allow the buffer to dynamically grow in 
      * size to accomodate large <code>char</code> arrays.
      *
      * @param c the <code>char</code> array to be appended to this
      * @param off the read offset for the array    
      * @param len the number of characters to append to this
      */   
     public void append(char[] c, int off, int len){
        ensureCapacity(count+ len);
        System.arraycopy(c,off,buf,count,len);
        count+=len;
     }
     
     /** 
      * This will add a <code>String</code> to the end of the buffer.
      * The buffer will not overflow with repeated uses of the 
      * <code>append</code>, it uses an <code>ensureCapacity</code>
      * method which will allow the buffer to dynamically grow in 
      * size to accomodate large <code>String</code> objects.
      *
      * @param str the <code>String</code> to be appended to this
      * @param off the read offset for the <code>String</code>
      * @param len the number of characters to append to this
      */   
     public void append(String str, int off, int len){
        ensureCapacity(count+ len);
        str.getChars(off,len,buf,count);  
        count += len;
     }
  
  
     /** 
      * This will add a <code>Template</code> to the end of this.
      * The buffer will not overflow with repeated uses of the 
      * <code>append</code>, it uses an <code>ensureCapacity</code> 
      * method which will allow the buffer to dynamically grow in 
      * size to accomodate large <code>Template</code> objects.
      *
      * @param text the <code>Template</code> to be appended 
      * @param off the read offset for the <code>Template</code>
      * @param len the number of characters to append to this
      */  
     public void append(Template text, int off, int len){
        append(text.buf, off, len);           
     }   
     
     /** 
      * This ensure that there is enough space in the buffer to allow
      * for more characters to be added. If the buffer is already 
      * larger than min then the buffer will not be expanded at all.
      *
      * @param min the minimum size needed for this buffer
      */     
     protected void ensureCapacity(int min) {
        if(buf.length < min) {
           int size = buf.length * 2;
           int max = Math.max(min, size);
           char[] temp = new char[max];         
           System.arraycopy(buf, 0, temp, 0, count); 
           buf = temp;
        }
     }  
     
     /** 
      * This will empty the <code>Template</code> so that the
      * <code>toString</code> paramater will return <code>null</code>. 
      * This is used so that the same <code>Template</code> can be 
      * recycled for different tokens.
      */
     public void clear(){
        cache = null;
        count = 0;
     }
    
     /** 
      * This will return the number of bytes that have been appended 
      * to the <code>Template</code>. This will return zero after 
      * the clear method has been invoked.
      *
      * @return the number of characters within this buffer object
      */
     public int length(){
        return count;
     }
  
     /** 
      * This will return the characters that have been appended to the 
      * <code>Template</code> as a <code>String</code> object.
      * If the <code>String</code> object has been created before then
      * a cached <code>String</code> object will be returned. This
      * method will return <code>null</code> after clear is invoked.
      *
      * @return the characters appended as a <code>String</code>
      */
     public String toString(){
        return new String(buf,0,count);
     }
  }   
  