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1   /*
2    * Copyright (C) 2006 uguu@users.sourceforge.jp, All Rights Reserved.
3    *
4    * Redistribution and use in source and binary forms, with or without
5    * modification, are permitted provided that the following conditions
6    * are met:
7    *
8    *    1. Redistributions of source code must retain the above copyright
9    *       notice, this list of conditions and the following disclaimer.
10   *
11   *    2. Redistributions in binary form must reproduce the above copyright
12   *       notice, this list of conditions and the following disclaimer in the
13   *       documentation and/or other materials provided with the distribution.
14   *
15   *    3. Neither the name of Clarkware Consulting, Inc. nor the names of its
16   *       contributors may be used to endorse or promote products derived
17   *       from this software without prior written permission. For written
18   *       permission, please contact clarkware@clarkware.com.
19   *
20   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
21   * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
22   * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
23   * CLARKWARE CONSULTING OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
24   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
26   * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
27   * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
28   * NEGLIGENCE OR OTHERWISE) ARISING IN  ANY WAY OUT OF THE USE OF THIS SOFTWARE,
29   * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30   */
31  
32  package jp.sourceforge.rpn_computer;
33  
34  import jp.sourceforge.rpn_computer.node.ExpressionStatementNode;
35  import jp.sourceforge.tokenizer.Tokenizer;
36  
37  /**
38   * <p>
39   * 通常の数式を解析し、抽象構文木を構築します。
40   * </p>
41   * 
42   * @author uguu@users.sourceforge.jp
43   */
44  public final class RpnParser {
45  
46      /**
47       * <p>
48       * 通常の数式を解析し、抽象構文木を構築します。
49       * </p>
50       * <p>
51       * 字句解析に失敗した場合、{@link jp.sourceforge.tokenizer.TokenizerException}例外をスローします。構文解析に失敗した場合、{@link ParseException}例外をスローします。
52       * </p>
53       * 
54       * @param expression
55       *            通常の数式。nullの場合、{@link NullPointerException}例外をスローします。
56       * @return 解析した結果の抽象構文木。
57       */
58      public RpnNode parse(String expression) {
59          // 引数をチェックします。
60          if (expression == null) {
61              throw new NullPointerException("expressionがnullです。");
62          }
63          // 構文解析します。
64          Tokenizer tokenizer = new Tokenizer(expression);
65          RpnNode node = new ExpressionStatementNode();
66          node.parse(tokenizer);
67          return node;
68      }
69  }