onetomanycrudcontroller.java

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package net.java.workeffort.webapp.action;

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

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

import net.java.workeffort.infrastructure.exception.IPropertyException;
import net.java.workeffort.infrastructure.view.ViewHelper;
import net.java.workeffort.service.domain.CollectionElement;
import net.java.workeffort.service.support.NoParentRowFkException;
import net.java.workeffort.service.support.OptimisticLockingException;
import net.java.workeffort.service.support.UniqueConstraintException;
import net.java.workeffort.webapp.support.FlowSetValueHelper;
import net.java.workeffort.webapp.support.InvalidSynchronizerTokenException;
import net.java.workeffort.webapp.support.WebappUtils;

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

/**
 * A generic CRUD controller for one to many relationship. Also has methods
 * which allows the user to set a value of a field using page flow. The command
 * object is stored in session scope.
 * <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 form view. Required</td>
 * </tr>
 * <tr>
 * <td>commandClass</td>
 * <td>null</td>
 * <td>The command class. Required</td>
 * </tr>
 * <tr>
 * <td>primaryKeyParameterName</td>
 * <td>null</td>
 * <td>Name of the request parameter which will be used as the primary key for
 * querying the object. Required. Expects to find a property by this name in the
 * command object</td>
 * </tr>
 * <tr>
 * <td>commandClass</td>
 * <td>null</td>
 * <td>The command class. Required</td>
 * </tr>
 * <tr>
 * <td>getObjectMethodName</td>
 * <td>null</td>
 * <td>The method name to retrive object in the service. Required</td>
 * </tr>
 * <tr>
 * <td>saveMethodName</td>
 * <td>null</td>
 * <td>The save method name in the service. Required</td>
 * </tr>
 * <tr>
 * <td>collectionPropertyName</td>
 * <td>null</td>
 * <td>The collection property name in the command class. Required</td>
 * </tr>
 * <tr>
 * <td>collectionElementClass</td>
 * <td>null</td>
 * <td>The class of the element stored in the collection. Required</td>
 * </tr>
 * </table>
 * @author Antony Joseph
 */
public class OneToManyCrudController extends BaseFormController {
    public static final String RESET = "reset";
    public static final String IGNORE = "ignore";
    public static final String ASSIGN_SELECTED_VALUE = "assignSelectedValue";
    public static final String EDIT_ROW = "editRow";
    public static final String ADD_ROW = "addRow";
    public static final String IGNORE_ROW = "ignoreRow";
    public static final String START_FLOW_SET_VALUE = "startFlowSetValue";
    public static final String CANCEL_FLOW_SET_VALUE = "cancelFlowSetValue";
    // The index into the collection for which the value will be set using a
    // flow.
    public static final String COLLECTION_IDX = "collectionIdx";
    // The target property name for which the value needs to be set.
    public static final String TARGET_PROPERTY_NAME_FOR_VALUE = "targetPropertyNameForValue";
    public static final String SUB_FLOW = "subFlow";
    public static final String SELECTED_VALUE = "selectedValue";

    // config parameters
    protected String primaryKeyParameter;
    protected String saveMethodName;
    protected String getObjectMethodName;
    protected Class collectionElementClass;
    protected String collectionPropertyName;

    // instance variables.
    private Method saveMethod;
    private Method getObjectMethod;
    protected Class primaryKeyClass;

    protected void init() {
        super.init();
        Validate.notNull(service, "Service cannot be null");
        Validate.notNull(getFormView(), "'formView' cannot be null");
        Validate.notNull(getCommandClass(), "'commandClass' cannot be null");
        Validate.notEmpty(primaryKeyParameter,
                "primaryKeyParameter cannot be null");
        Validate.notEmpty(getObjectMethodName,
                "'getObjectMethodName' cannot be null");
        Validate.notEmpty(saveMethodName, "'saveMethodName' cannot be null");
        Validate.notNull(collectionPropertyName,
                "'collectionPropertyName' cannot be null");
        Validate.notNull(collectionElementClass,
                "'collectionElementClass' cannot be null");
        // get the primary key class using the configured primaryKeyParameter
        // and command object Class
        primaryKeyClass = WebappUtils.getPropertyType(primaryKeyParameter,
                getCommandClass());

        // get the save/getObject methods from the service
        saveMethod = getServiceMethod(service.getClass(), saveMethodName,
                new Class[] { getCommandClass() });
        getObjectMethod = getServiceMethod(service.getClass(),
                getObjectMethodName, new Class[] { primaryKeyClass });

        // make sure the form is stored in message scope.
        setSessionForm(true);
        setValidateOnBinding(false);
    }

    public void setPrimaryKeyParameter(String primaryKeyParameter) {
        this.primaryKeyParameter = primaryKeyParameter;
    }

    public void setGetObjectMethodName(String getObjectMethodName) {
        this.getObjectMethodName = getObjectMethodName;
    }

    public void setSaveMethodName(String saveMethodName) {
        this.saveMethodName = saveMethodName;
    }

    public void setCollectionPropertyName(String collectionPropertyName) {
        this.collectionPropertyName = collectionPropertyName;
    }

    public void setCollectionElementClass(Class elementClass) {
        this.collectionElementClass = elementClass;
    }

    protected Object formBackingObject(HttpServletRequest request)
            throws Exception {
        if (logger.isInfoEnabled())
            logger.info("formBackingObject() invoked.");

        // Note that a reset is handle like a query.
        if (QUERY.equals(request.getParameter(DISPATCH_PARAMETER_NAME))
                || RESET.equals(request.getParameter(DISPATCH_PARAMETER_NAME))) {
            Object pk = getParameterValue(request, primaryKeyParameter,
                    primaryKeyClass);
            return getObject(request, pk);
        }
        else if (NEW.equals(request.getParameter(DISPATCH_PARAMETER_NAME))) {
            saveToken(request);
            // let the jsp know to display form in insert mode.
            saveViewHelper(request, ViewHelper.INSERT_MODE);
            return createCommand();
        }
        else
            throw new RuntimeException(
                    "formBackingObject(). dispatch is not 'query' or 'insert'. dispatch="
                            + request.getParameter(DISPATCH_PARAMETER_NAME));
    }

    protected boolean isFormSubmission(HttpServletRequest request) {
        // reset is a POST. Handle it like a GET.
        if (RESET.equals(request.getParameter(DISPATCH_PARAMETER_NAME))) {
            // reset is handled like an initial query
            return false;
        }
        else if (ASSIGN_SELECTED_VALUE.equals(request
                .getParameter(DISPATCH_PARAMETER_NAME))
                || CANCEL_FLOW_SET_VALUE.equals(request
                        .getParameter(DISPATCH_PARAMETER_NAME)))
            //assignSelectedValue and cancelFlowSetValue are GETs.
            //Handle them like a form submission.
            return true;
        else
            return super.isFormSubmission(request);
    }

    protected ModelAndView processFormSubmission(HttpServletRequest request,
            HttpServletResponse response, Object command, BindException errors)
            throws Exception {
        if (!isTokenValid(request)) {
            clearToken(request);
            throw new InvalidSynchronizerTokenException(
                    "Invalid token. dispatch="
                            + request.getParameter(DISPATCH_PARAMETER_NAME));
        }

        if (ADD_ROW.equals(request.getParameter(DISPATCH_PARAMETER_NAME))
                || IGNORE_ROW.equals(request
                        .getParameter(DISPATCH_PARAMETER_NAME))
                || EDIT_ROW.equals(request
                        .getParameter(DISPATCH_PARAMETER_NAME))
                || START_FLOW_SET_VALUE.equals(request
                        .getParameter(DISPATCH_PARAMETER_NAME))
                || CANCEL_FLOW_SET_VALUE.equals(request
                        .getParameter(DISPATCH_PARAMETER_NAME))
                || ASSIGN_SELECTED_VALUE.equals(request
                        .getParameter(DISPATCH_PARAMETER_NAME))) {
            //call onSubmit() even if there are bind errors
            logger.info(request.getParameter(DISPATCH_PARAMETER_NAME)
                    + " -> processing submit");
            return onSubmit(request, response, command, errors);
        }
        else {
            return super.processFormSubmission(request, response, command,
                    errors);
        }
    }

    protected ModelAndView onSubmit(HttpServletRequest request,
            HttpServletResponse response, Object command, BindException errors)
            throws Exception {
        if (logger.isInfoEnabled())
            logger.info("onSubmit() invoked.");

        if (SAVE.equals(request.getParameter(DISPATCH_PARAMETER_NAME))) {
            return save(request, response, command, errors);
        }
        else if (EDIT_ROW.equals(request.getParameter(DISPATCH_PARAMETER_NAME))) {
            return editRow(request, response, command, errors);
        }
        else if (ADD_ROW.equals(request.getParameter(DISPATCH_PARAMETER_NAME))) {
            return addRow(request, response, command, errors);
        }
        else if (IGNORE_ROW.equals(request
                .getParameter(DISPATCH_PARAMETER_NAME))) {
            return ignoreRow(request, response, command, errors);
        }
        else if (START_FLOW_SET_VALUE.equals(request
                .getParameter(DISPATCH_PARAMETER_NAME))) {
            return startFlowSetValue(request, response, command, errors);
        }
        else if (ASSIGN_SELECTED_VALUE.equals(request
                .getParameter(DISPATCH_PARAMETER_NAME))) {
            return assignSelectedValue(request, response, command, errors);
        }
        else if (CANCEL_FLOW_SET_VALUE.equals(request
                .getParameter(DISPATCH_PARAMETER_NAME))) {
            return cancelFlowSetValue(request, response, command, errors);
        }
        else
            throw new RuntimeException("onSubmit(). invalid dispatch:"
                    + request.getParameter(DISPATCH_PARAMETER_NAME));

    }

    /**
     * Just redisplays the view so that the pertinent row is editable.. Note
     * that no call to the service layer is made.
     * @param request The request
     * @param response The response
     * @param command The command object
     * @param errors The bind Exception
     * @return model and view
     * @throws Exception
     */
    protected ModelAndView editRow(HttpServletRequest request,
            HttpServletResponse response, Object command, BindException errors)
            throws Exception {
        if (logger.isInfoEnabled())
            logger.info("editRow() invoked.");
        // just redisplay the form. The 'update' submitted value for processType
        // (of the collection element) will be used by the jsp to render the
        // form appropriately. Also there is no need to display errors.
        request.setAttribute(SKIP_ERRORS, "skip");
        return showForm(request, response, errors);
    }