sort – sortMode =“multiple”和lazy =“true”在分页期间清除multisort meta

我只是在展示代码中为“ DataTable – Lazy Loading”启用了多个排序

datatableLazy.xhtml

<html lang="en" xmlns="http://www.w3.org/1999/xhtml"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:p="http://primefaces.org/ui"
xmlns:ui="http://java.sun.com/jsf/facelets">
<h:head>
<title>CarDataTable</title>
</h:head>
<h:body>
<h:form id="form">
    <p:dataTable var="car" value="#{tableBean.lazyModel}" paginator="true"
        rows="10"
        paginatorTemplate="{RowsPerPageDropdown} {FirstPageLink} {PrevIoUsPageLink} {CurrentPageReport} {NextPageLink} {LastPageLink}"
        rowsPerPageTemplate="5,10,15" id="carTable" lazy="true"
        sortMode="multiple">

        <p:ajax event="rowSelect" listener="#{tableBean.onRowSelect}"
            update=":form:display" oncomplete="carDialog.show()" />

        <p:column headerText="Model" sortBy="#{car.model}"
            filterBy="#{car.model}">
            <h:outputText value="#{car.model}" />
        </p:column>

        <p:column headerText="Year" sortBy="#{car.year}"
            filterBy="#{car.year}">
            <h:outputText value="#{car.year}" />
        </p:column>

        <p:column headerText="Manufacturer" sortBy="#{car.manufacturer}"
            filterBy="#{car.manufacturer}">
            <h:outputText value="#{car.manufacturer}" />
        </p:column>

        <p:column headerText="Color" sortBy="#{car.color}"
            filterBy="#{car.color}">
            <h:outputText value="#{car.color}" />
        </p:column>
    </p:dataTable>
</h:form>
</h:body>
</html>

TableBean.java

package com.solartis.primefaces.sample;

import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

import javax.faces.bean.ManagedBean;

import org.primefaces.model.LazyDataModel;

@ManagedBean
public class TableBean {

private LazyDataModel<Car> lazyModel;

private Car selectedCar;

private List<Car> cars = new ArrayList<Car>();

private final static String[] colors;

private final static String[] manufacturers;

static {
    colors = new String[10];
    colors[0] = "Black";
    colors[1] = "White";
    colors[2] = "Green";
    colors[3] = "Red";
    colors[4] = "Blue";
    colors[5] = "Orange";
    colors[6] = "Silver";
    colors[7] = "Yellow";
    colors[8] = "Brown";
    colors[9] = "Maroon";

    manufacturers = new String[10];
    manufacturers[0] = "Mercedes";
    manufacturers[1] = "BMW";
    manufacturers[2] = "Volvo";
    manufacturers[3] = "Audi";
    manufacturers[4] = "Renault";
    manufacturers[5] = "Opel";
    manufacturers[6] = "Volkswagen";
    manufacturers[7] = "Chrysler";
    manufacturers[8] = "Ferrari";
    manufacturers[9] = "Ford";
}

public TableBean() {
    populateRandomCars(cars,50);
    lazyModel = new LazyCarDataModel(cars);
}

public Car getSelectedCar() {
    return selectedCar;
}

public void setSelectedCar(Car selectedCar) {
    this.selectedCar = selectedCar;
}

public LazyDataModel<Car> getLazyModel() {
    return lazyModel;
}

private void populateRandomCars(List<Car> list,int size) {
    for (int i = 0; i < size; i++) {
        list.add(new Car(getRandomModel(),getRandomYear(),getRandomManufacturer(),getRandomColor()));
    }
}

private String getRandomColor() {
    return colors[(int) (Math.random() * 10)];
}

private String getRandomManufacturer() {
    return manufacturers[(int) (Math.random() * 10)];
}

private int getRandomYear() {
    return (int) (Math.random() * 50 + 1960);
}

private String getRandomModel() {
    return UUID.randomUUID().toString().substring(0,8);
}
}

LazyCarDataModel.java

package com.solartis.primefaces.sample;

import java.util.ArrayList;

/**
 * Dummy implementation of LazyDataModel that uses a list to mimic a real 
   datasource like a database.
 */
public class LazyCarDataModel extends LazyDataModel<Car> {

private List<Car> datasource;

public LazyCarDataModel(List<Car> datasource) {
    this.datasource = datasource;
}

@Override
public Car getRowData(String rowKey) {
    for(Car car : datasource) {
        if(car.getModel().equals(rowKey))
            return car;
    }

    return null;
}

@Override
public void setRowIndex(int rowIndex) {

    if (rowIndex == -1 || getPageSize() == 0) {
        super.setRowIndex(-1);
    } else
        super.setRowIndex(rowIndex % getPageSize());
}

@Override
public Object getRowKey(Car car) {
    return car.getModel();
}

@Override
public List<Car> load(int first,int pageSize,List<SortMeta> multiSortMeta,Map<String,String> filters) {

    System.out.println("\nTHE INPUT PARAMETER VALUE OF LOAD METHOD :   
    \t"+"first=" + first + ",pagesize=" + pageSize + ",multiSortMeta=" + 
    multiSortMeta + " filter:" + filters);

    System.out.println("\nTHE MULTISORTMeta CONTENT  : \t");

    if (multiSortMeta != null) {
        for (SortMeta sortMeta : multiSortMeta) {
            System.out.println("SORTFIELD:" +sortMeta.getSortField());
            System.out.println("SORTORDER:" +sortMeta.getSortOrder());
                    System.out.println("SORTFUNCTION:"
                                                         +sortMeta.getSortFunction());
            System.out.println("COLUMN:" +sortMeta.getColumn());
            System.out.println("CLASS:" +sortMeta.getClass());
        }
    }

    List<Car> data = new ArrayList<Car>();

    //filter
    for(Car car : datasource) {
        boolean match = true;

        for(Iterator<String> it = filters.keySet().iterator(); it.hasNext();) {
            try {
                String filterProperty = it.next();
                String filterValue = filters.get(filterProperty);
                String fieldValue =  String.valueOf(car.getClass().
                                getField(filterProperty).get(car));

                if(filterValue == null || fieldValue.startsWith(filterValue)) {
                    match = true;
                }
                else {
                    match = false;
                    break;
                }
            } catch(Exception e) {
                match = false;
            } 
        }

        if(match) {
            data.add(car);
        }
    }


    //rowCount
    int dataSize = data.size();
    this.setRowCount(dataSize);

    //paginate
    if(dataSize > pageSize) {
        try {
            return data.subList(first,first + pageSize);
        }
        catch(IndexOutOfBoundsException e) {
            return data.subList(first,first + (dataSize % pageSize));
        }
    }
    else {
        return data;
    }
}
}

它很好用,除非我用多列排序分页,带有List< SortMeta>的load()方法.没有给我当前排序到其他页面的列详细信息,不像使用String sortField的load()方法,SortOrder sortOrder给出了那些排序细节.

例如:

>点击“制造商”中的排序箭头,然后按住Ctrl键点击“年份”的排序箭头

>你会得到load()方法的排序列详细信息(我在load方法中打印了输入参数值).

>现在,做分页.这里load()方法无法给出排序列的详细信息

>不仅是分页,如果在单击排序列后输入列过滤器值,则存在同样的问题

我怎样才能解决这个问题?

解决方法

我暂时解决了这个问题……
有一个sessioncoped托管bean用于存储排序列的详细信息,以便在分页期间进入load(),
喜欢:-
@ManagedBean
@SessionScoped

public class StoreSortColumnDetail implements Serializable{


    /** holds multisort values**/
private List<SortMeta> mMultiSortMeta;


public List<SortMeta> getMultiSortMeta() {
    return mMultiSortMeta;
}

public void setMultiSortMeta(List<SortMeta> multiSortMeta) {
    mMultiSortMeta = multiSortMeta;
}

public void clearMultiSortMeta() {
    if(this.mMultiSortMeta != null)
        this.mMultiSortMeta.clear();

}
}

并在load()中使用它,如下所示:

@Override
public List<Car> load(int first,String> filters) {

/** Instance to the SessionScoped scoped StoreSortColumnDetail managed bean*/
@ManagedProperty(value="#{StoreSortColumnDetail }")
private StoreSortColumnDetail storeSortColumnDetail ;

public void setStoreSortColumnDetail (StoreSortColumnDetail sortColumnDetail ) {
    this.storeSortColumnDetail = sortColumnDetail ;
}

/** to hold the handled sort column detail**/
List<SortMeta> handledMultiSortMeta = new ArrayList<SortMeta>();

/*Here starts the multisortMeta handling process*/
   /** check for List<SortMeta> for null**/
if(multiSortMeta != null ) {

    /** updates StoreSortColumnDetail's List<SortMeta> with Load()'s List<SortMeta>**/
    storeSortColumnDetail.setMultiSortMeta(multiSortMeta);
    handledMultiSortMeta  = multiSortMeta;
} 
/** check for List<SortMeta> for notnull **/
else if (multiSortMeta == null) {

    /**assigns Load()'s List<SortMeta> with StoreSortColumnDetail's List<SortMeta>**/
    handledMultiSortMeta  = storeSortColumnDetail.getMultiSortMeta();
} 


   /*Now u have handled multisortMeta from load()...
     and u can process now from handledMultiSortMeta*/
}

我希望你知道我是如何处理的,如果不是亲密的我……但这是一种暂时的方式,需要通过primefaces方式处理它…

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