• (转)在JAVA实现DataTable对象(三)——DataTable对象实现


    大家都是行家,我就直接上代码了,我这个代码应该还是能看懂的,嘻嘻….
       1:  import java.util.ArrayList;
       2:  import java.util.List;
       3:   
       6:   
       7:  public final class DataTable {
       8:   
       9:      private DataRowCollection rows; //用于保存DataRow的集合对象
      10:      private DataColumnCollection columns; //用于保存DataColumn的对象
      11:      private String tableName; //表名
      12:      private boolean readOnly = false;
      13:      private int nextRowIndex = 0;
      14:      private DataExpression dataExpression;
      15:      private Object tag;
      16:   
      17:      public DataTable() {
      18:          this.columns = new DataColumnCollection();
      19:          this.rows = new DataRowCollection();
      20:          this.rows.setColumns(columns);
      21:          dataExpression = new DataExpression(this);
      22:      }
      23:   
      24:      public DataTable(String dataTableName) {
      25:          this();
      26:          this.tableName = dataTableName;
      27:      }
      28:   
      29:      public int getTotalCount() {
      30:          return rows.size();
      31:      }
      32:   
      33:      public boolean isReadOnly() {
      34:          return this.readOnly;
      35:      }
      36:   
      37:      public void setReadOnly(boolean readOnly) {
      38:          this.readOnly = readOnly;
      39:      }
      40:   
      41:      /**  
      42:       * 功能描述:  返回表名
      43:       * @param    
      44:       */
      45:      public String getTableName() {
      46:          return this.tableName;
      47:      }
      48:   
      49:      /**  
      50:       * 功能描述:  设置表名
      51:       * @param    
      52:       */
      53:      public void setTableName(String tableName) {
      54:          this.tableName = tableName;
      55:      }
      56:   
      57:      /**  
      58:       * 功能描述:  返回该表引用的封装类
      59:       * @param
      60:       * @return: DataRowCollection    
      61:       */
      62:      public DataRowCollection getRows() {
      63:          return this.rows;
      64:      }
      65:   
      66:      public DataColumnCollection getColumns() {
      67:          return this.columns;
      68:      }
      69:   
      70:      /**  
      71:       * 功能描述:  获取指定行指定列的数据
      72:       * @param
      73:       * @return: Object    
      74:       */
      75:   
      76:      public Object getValue(int row,
      77:              String colName) {
      78:          return this.rows.get(row).getValue(colName);
      79:      }
      80:   
      81:      public Object getValue(int row,
      82:              int col) {
      83:          return this.rows.get(row).getValue(col);
      84:      }
      85:   
      86:      /**  
      87:       * 功能描述:  为该表数据新建一行
      88:       * @param
      89:       * @return: DataRow     
      90:       */
      91:      public DataRow newRow() throws Exception {
      92:          DataRow tempRow = new DataRow(this);
      93:          nextRowIndex = nextRowIndex < this.rows.size() ? this.rows.size()
      94:                  : nextRowIndex;
      95:          tempRow.setColumns(this.columns);
      96:          tempRow.setRowIndex(nextRowIndex++);
      97:          return tempRow;
      98:      }
      99:   
     100:      public void setValue(int row,
     101:              int col,
     102:              Object value) {
     103:          this.rows.get(row).setValue(col, value);
     104:      }
     105:   
     106:      public void setValue(int row,
     107:              String colName,
     108:              Object value) {
     109:          this.rows.get(row).setValue(colName, value);
     110:      }
     111:   
     112:      /**  
     113:       * @param tag
     114:       */
     115:      public void setTag(Object tag) {
     116:          this.tag = tag;
     117:      }
     118:   
     119:      /**  
     120:       * @return  the tag   
     121:      */
     122:      public Object getTag() {
     123:          return tag;
     124:      }
     125:   
     126:      public DataColumn addColumn(String columnName,
     127:              int dataType) throws Exception {
     128:          return this.columns.addColumn(columnName, dataType);
     129:      }
     130:   
     131:      public boolean addRow(DataRow row) throws Exception {
     132:          if (row.getRowIndex() > this.rows.size())
     133:              row.setRowIndex(this.rows.size());
     134:          return this.rows.add(row);
     135:      }
     136:   
     137:      //以下为数据表扩展方法实现集合
     138:      /**  
     139:       * 功能描述:  返回符合过滤条件的数据行集合,并返回
     140:       * @param
     141:       * @return: DataTable    
     142:       */
     143:      public List<DataRow> select(String filterString) {
     144:          List<DataRow> rows = new ArrayList<DataRow>();
     145:          if (StringUtil.isNotEmpty(filterString)) {
     146:              for (Object row : this.rows) {
     147:                  DataRow currentRow = (DataRow) row;
     148:                  if ((Boolean) dataExpression.compute(filterString,
     149:                          currentRow.getItemMap())) {
     150:                      rows.add(currentRow);
     151:                  }
     152:              }
     153:              return rows;
     154:          } else {
     155:              return this.rows;
     156:          }
     157:      }
     158:   
     159:      /**  
     160:       * 功能描述:  对当前表进行查询 过滤,并返回指定列集合拼装的DataTable对象
     161:       * @param
     162:       * @return: DataTable    
     163:       */
     164:      public DataTable select(String filterString,
     165:              String[] columns,
     166:              boolean distinct) throws Exception {
     167:          DataTable result = new DataTable();
     168:          List<DataRow> rows = select(filterString);
     169:          //构造表结构
     170:          for (String c : columns) {
     171:              DataColumn dc = this.columns.get(c);
     172:              DataColumn newDc = new DataColumn(dc.getColumnName(),
     173:                      dc.getDataType());
     174:              newDc.setCaptionName(dc.getCaptionName());
     175:              result.columns.add(newDc);
     176:          }
     177:          //填充数据
     178:          for (DataRow r : rows) {
     179:              DataRow newRow = result.newRow();
     180:              newRow.copyFrom(r);
     181:              result.addRow(newRow);
     182:          }
     183:          return result;
     184:      }
     185:   
     186:      public DataTable select(String tableName,
     187:              String selectField,
     188:              String filterString,
     189:              String groupField) {
     190:          DataTable result = new DataTable();
     191:          //
     192:          return result;
     193:      }
     194:   
     195:      /**  
     196:       * 功能描述:  根据指定表达式对符合过滤条件的数据进行计算
     197:       * @param
     198:       * @return: Object
     199:       * @author: James Cheung
     200:       * @version: 2.0 
     201:       */
     202:      public Object compute(String expression,
     203:              String filter) {
     204:          return dataExpression.compute(expression, select(filter));
     205:      }
     206:   
     207:      public Object max(String columns,
     208:              String filter) {
     209:          return null;
     210:      }
     211:   
     212:      public Object min(String columns,
     213:              String filter) {
     214:          return null;
     215:      }
     216:   
     217:      public Object avg(String columns,
     218:              String filter) {
     219:          return null;
     220:      }
     221:   
     222:      public Object max(String columns,
     223:              String filter,
     224:              String groupBy) {
     225:          return null;
     226:      }
     227:   
     228:      public Object min(String columns,
     229:              String filter,
     230:              String groupBy) {
     231:          return null;
     232:      }
     233:   
     234:      public Object avg(String columns,
     235:              String filter,
     236:              String groupBy) {
     237:          return null;
     238:      }
     239:   
     240:      private List<DataColumn> getColumns(String colString) {
     241:          List<DataColumn> columns = new ArrayList<DataColumn>();
     242:   
     243:          return columns;
     244:      }
     245:  }
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  • 原文地址:https://www.cnblogs.com/wangyt223/p/4168211.html
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