ResultSetMock

ResultSetMock.java

import org.apache.commons.lang.NotImplementedException;
import org.apache.commons.lang.StringUtils;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.sql.ResultSet;
import java.util.HashMap;

public class ResultSetMock {

    private HashMap<String, Object> columnName;
    private HashMap<Integer,Object> columnId;
    private int id;

    public ResultSetMock() {
        columnName = new HashMap<String, Object>();
        columnId = new HashMap<Integer, Object>();
        id = 1;
    }

    public static ResultSetMock.Builder createResultSetMockBuilder() {
        return new ResultSetMock().new Builder();
    }

    public class Builder {
        public Builder addResult(String key, Object value) {
            columnName.put(key, value);
            columnId.put(id, value);
            id++;
            return this;
        }

        public ResultSet build() {
            ResultSetInvocationHandler handler = ResultSetMock.this.new ResultSetInvocationHandler();

            Class<?>[] classes = {ResultSet.class};
            return (ResultSet) Proxy.newProxyInstance(ResultSetMock.class.getClassLoader(), classes, handler);
        }
    }

    private class ResultSetInvocationHandler implements InvocationHandler {
        public Object invoke(Object o, Method method, Object[] objects) throws Throwable {
            if (StringUtils.startsWith(method.getName(), "get")) {
                if (objects.length > 0 && objects[0] instanceof Integer) {
                    return columnId.get((Integer) objects[0]);
                }
                else if (objects.length > 0 && objects[0] instanceof String) {
                    return columnName.get((String) objects[0]);
                }
            }
            throw new NotImplementedException();
        }
    }
}

Usage.java

import org.junit.Test;

import java.sql.ResultSet;

public class Usage {
    @Test
    public void test() {
        ResultSet resultSetMock = ResultSetMock.createResultSetMockBuilder()
                .addResult("COLUMN1", "somevalue")
                .addResult("COLUMN2", 1)
                .build();
    }
}