searchcontroller.java

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package net.java.workeffort.webapp.action;

import java.lang.reflect.Method;
import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.java.workeffort.service.domain.PageResult;
import net.java.workeffort.service.domain.PaginationQuery;
import net.java.workeffort.webapp.support.WebConstants;

import org.apache.commons.lang.Validate;
import org.springframework.validation.BindException;
import org.springframework.web.servlet.ModelAndView;

/**
 * A generic search controller for queries and pagination.
 * <p>
 * <b>Exposed configuration properties: (See BaseFormController also) </b> <br>
 * <table border="1">
 * <tr>
 * <td><b>Name </b></td>
 * <td><b>Default </b></td>
 * <td><b>Description </b></td>
 * </tr>
 * <tr>
 * <td>service</td>
 * <td>null</td>
 * <td>The service. Required</td>
 * </tr>
 * <tr>
 * <td>formView</td>
 * <td>null</td>
 * <td>The initial query view. Required</td>
 * </tr>
 * <tr>
 * <td>successView</td>
 * <td>null</td>
 * <td>The success view which shows the search results. Generally a view which
 * supports pagination. Required</td>
 * </tr>
 * <tr>
 * <td>commandClass</td>
 * <td>null</td>
 * <td>The command class. Required</td>
 * </tr>
 * <tr>
 * <td>queryMethodName</td>
 * <td>null</td>
 * <td>The query method name in the service. Required</td>
 * </tr>
 * <tr>
 * <td>pageSize</td>
 * <td>10</td>
 * <td>The number of records to be displayed for pagination queries</td>
 * </tr>
 * </table>
 * @author Antony Joseph
 */
public class SearchController extends BaseFormController {

    private Method queryMethod;
    private String queryMethodName;
    protected Integer pageSize;

    protected void init() {
        super.init();
        Validate.notNull(service, "Service cannot be null");
        Validate.notNull(getFormView(), "'formView' cannot be null");
        Validate.notNull(getSuccessView(), "'successView' cannot be null");
        Validate.notNull(getCommandClass(), "'commandClass' cannot be null");
        Validate.notNull(queryMethodName, "'queryMethodName' cannot be null");
        if (pageSize == null)
            pageSize = new Integer(10);

        // get the page result method. Should be available in the service
        queryMethod = getServiceMethod(service.getClass(), queryMethodName,
                new Class[] { getCommandClass() });

        setValidateOnBinding(false);
    }

    public void setPageSize(Integer pageSize) {
        this.pageSize = pageSize;
    }

    public void setQueryMethodName(String queryMethodName) {
        this.queryMethodName = queryMethodName;
    }

    protected boolean isFormSubmission(HttpServletRequest request) {
        return QUERY.equals(request.getParameter(DISPATCH_PARAMETER_NAME));
    }

    /**
     * Invokes the query method on the service. Makes the following attributes
     * available in the request scope for the jsps to render the result
     * appropriately: 'resultList' - The query result, 'pageSize' - The page
     * size, 'rowCount' - The total row count of the initial query.
     * @param request the request
     * @param response the response
     * @param command the query parameters
     * @param errors the bind exception
     * @return the model and view
     */
    protected ModelAndView onSubmit(HttpServletRequest request,
            HttpServletResponse response, Object command, BindException errors)
            throws Exception {

        if (logger.isInfoEnabled())
            logger.info("onSubmit invoked.");

        if (command instanceof PaginationQuery)
           return  getPaginationResult(request, response, command, errors);
        else
            return getResult(request, response, command, errors);

    }

    protected ModelAndView getPaginationResult(HttpServletRequest request,
            HttpServletResponse response, Object command, BindException errors)
            throws Exception {

        PaginationQuery paginationQuery = (PaginationQuery) command;

        // take care of the info required by the datagrid.
        paginationQuery.setPageSize(this.pageSize);
        if (paginationQuery.getRowCount() == null) {
            paginationQuery.setPageIndex(new Integer(0));
        }

        String pageIndexStr = request
                .getParameter(WebConstants.DATAGRID_PAGE_INDEX);
        if (pageIndexStr != null && pageIndexStr.length() > 0)
            paginationQuery.setPageIndex(new Integer(pageIndexStr));

        // set the sortOrder.
        // Negative values or 0 mean ascending as per the Datagrid taglibs.
        // The dynamic SQL queries are written in such a way that if the value
        // for sortOrder is NOT NULL it means descending, otherwise,
        // the queries will default to ascending.
        String orderIndex = request
                .getParameter(WebConstants.DATAGRID_ORDER_INDEX);
        if (orderIndex != null && !orderIndex.equals("0")) {
            if (!(orderIndex.startsWith("-"))) {
                if (logger.isInfoEnabled())
                    logger.info("setting sortOrder to DESC");
                paginationQuery.setSortOrder("DESC");
            }
        }

        //PageResult result = (PageResult) queryMethod.invoke(service,
        //        new Object[] { command });

        PageResult result = (PageResult) query(request, command);

        // set result attributes so that the Jsps can find it.
        request.setAttribute("resultList", result.getRows());
        request.setAttribute("pageSize", paginationQuery.getPageSize());
        request.setAttribute("rowCount", result.getRowCount());

        return new ModelAndView(getSuccessView());
    }
    
    protected ModelAndView getResult(HttpServletRequest request,
            HttpServletResponse response, Object command, BindException errors)
            throws Exception {
        List resultList = (List) query(request, command);
        return new ModelAndView(getSuccessView(), "resultList", resultList);
    }

    /**
     * Invokes the query method on the service layer
     * @param request The request
     * @param command The query object
     * @return the page result
     * @throws Exception
     */
    protected Object query(HttpServletRequest request, Object command)
            throws Exception {
        return queryMethod.invoke(service,
                new Object[] { command });
    }
}