genericpersistencemanager.java

数据访问器

package jsx.szu.edu.cn.dao;

import java.awt.List;
import java.util.Iterator;

public class GenericPersistenceManager implements IPersistenceManager{

	public void delete(String table, Row selectionRow) throws DataException {
		// TODO Auto-generated method stub
		
	}

	public void insert(String table, List rows) throws DataException {
		// TODO Auto-generated method stub
		
	}

	public List read(String table, String[] columns, Row selectionRow, String[] sortColumns) throws DataException {
		// TODO Auto-generated method stub
		return null;
	}

	public void update(String table, Row selectionRow, Row updateRow) throws DataException {
		// TODO Auto-generated method stub
		
	}
	
	 private String generateLiteralValue(Object literalValue) 
	 {

			StringBuffer buffer=new StringBuffer();

			if(!(literalValue instanceof Number))

				buffer.append("'");

			buffer.append(literalValue);

			if (!(literalValue instanceof Number))

				buffer.append("'");

			return buffer.toString();

	}
	 
	 private String generateWhereClause(Row selectionRow) 
	 {

		    StringBuffer buffer=new StringBuffer();

		    buffer.append(" WHERE ");

		    boolean firstColumn=true;

		    for(Iterator i=selectionRow.columns();i.hasNext();)
		    {
		    	if (!firstColumn)
		    		buffer.append(" AND ");
		    	else
		    		firstColumn=false;

		      	String column=(String)i.next();

		    	buffer.append(column);

		    	buffer.append(" = ");

		    	Object columnValue=selectionRow.getColumnValue(column);

		    	buffer.append(generateLiteralValue(columnValue));

		    }

		    return buffer.toString();

	    }

}