/**
  * 将分支数据转成Query逻辑
  *
  * @return
  */
 List<Query> toQueries(String fieldName) {
   List<Query> queries = new ArrayList<Query>(1);
   // 生成当前branch 的query
   if (lexeme != null) {
     queries.add(new TermQuery(new Term(fieldName, lexeme.getLexemeText())));
   }
   // 生成child branch 的query
   if (acceptedBranchs != null && acceptedBranchs.size() > 0) {
     if (acceptedBranchs.size() == 1) {
       Query onlyOneQuery = optimizeQueries(acceptedBranchs.get(0).toQueries(fieldName));
       if (onlyOneQuery != null) {
         queries.add(onlyOneQuery);
       }
     } else {
       BooleanQuery orQuery = new BooleanQuery();
       for (TokenBranch childBranch : acceptedBranchs) {
         Query childQuery = optimizeQueries(childBranch.toQueries(fieldName));
         if (childQuery != null) {
           orQuery.add(childQuery, Occur.SHOULD);
         }
       }
       if (orQuery.getClauses().length > 0) {
         queries.add(orQuery);
       }
     }
   }
   // 生成nextBranch的query
   if (nextBranch != null) {
     queries.addAll(nextBranch.toQueries(fieldName));
   }
   return queries;
 }
  /**
   * 单连续字窜(不带空格符)单Field查询分析
   *
   * @param field
   * @param query
   * @return
   */
  public static Query parse(String field, String query) {
    if (field == null) {
      throw new IllegalArgumentException("parameter \"field\" is null");
    }

    if (query == null || "".equals(query.trim())) {
      return new TermQuery(new Term(field));
    }

    // 从缓存中取出已经解析的query生产的TokenBranch
    TokenBranch root = getCachedTokenBranch(query);
    if (root != null) {
      return optimizeQueries(root.toQueries(field));
    } else {
      // System.out.println(System.currentTimeMillis());
      root = new TokenBranch(null);
      // 对查询条件q进行分词
      StringReader input = new StringReader(query.trim());
      IKSegmentation ikSeg = new IKSegmentation(input, isMaxWordLength);
      try {
        for (Lexeme lexeme = ikSeg.next(); lexeme != null; lexeme = ikSeg.next()) {
          // 处理词元分支
          root.accept(lexeme);
        }
      } catch (IOException e) {
        e.printStackTrace();
      }
      // 缓存解析结果的博弈树
      cachedTokenBranch(query, root);
      return optimizeQueries(root.toQueries(field));
    }
  }
    /**
     * 组合词元分支
     *
     * @param _lexeme
     * @return 返回当前branch能否接收词元对象
     */
    boolean accept(Lexeme _lexeme) {

      /*
       * 检查新的lexeme 对当前的branch 的可接受类型
       * acceptType : REFUSED  不能接受
       * acceptType : ACCEPTED 接受
       * acceptType : TONEXT   由相邻分支接受
       */
      int acceptType = checkAccept(_lexeme);
      switch (acceptType) {
        case REFUSED:
          // REFUSE 情况
          return false;

        case ACCEPTED:
          if (acceptedBranchs == null) {
            // 当前branch没有子branch,则添加到当前branch下
            acceptedBranchs = new ArrayList<TokenBranch>(2);
            acceptedBranchs.add(new TokenBranch(_lexeme));
          } else {
            boolean acceptedByChild = false;
            // 当前branch拥有子branch,则优先由子branch接纳
            for (TokenBranch childBranch : acceptedBranchs) {
              acceptedByChild = childBranch.accept(_lexeme) || acceptedByChild;
            }
            // 如果所有的子branch不能接纳,则由当前branch接纳
            if (!acceptedByChild) {
              acceptedBranchs.add(new TokenBranch(_lexeme));
            }
          }
          // 设置branch的最大右边界
          if (_lexeme.getEndPosition() > this.rightBorder) {
            this.rightBorder = _lexeme.getEndPosition();
          }
          break;

        case TONEXT:
          // 把lexeme放入当前branch的相邻分支
          if (this.nextBranch == null) {
            // 如果还没有相邻分支,则建立一个不交叠的分支
            this.nextBranch = new TokenBranch(null);
          }
          this.nextBranch.accept(_lexeme);
          break;
      }

      return true;
    }
 public boolean equals(Object o) {
   if (o == null) {
     return false;
   }
   if (this == o) {
     return true;
   }
   if (o instanceof TokenBranch) {
     TokenBranch other = (TokenBranch) o;
     if (this.lexeme == null || other.getLexeme() == null) {
       return false;
     } else {
       return this.lexeme.equals(other.getLexeme());
     }
   } else {
     return false;
   }
 }