[英]ExtendedDataTable in RichFaces 4: DataModel handling
我还有一个问题,与我在一月份发布的问题有些相关。 我有一个列表,它是rich:extendedDataTable组件,它会随着用户在一个单独的文本框中键入他的搜索条件而动态更新(即,用户键入前4个字符,并且在他不断键入时会显示结果)列表更改)。 最后,当我使用RichFaces 3时,它工作正常,但是当我升级到RichFaces 4时,我遇到了各种各样的编译问题。 似乎不再可以访问以下类,并且似乎没有合适的替代品:
org.richfaces.model.DataProvider
org.richfaces.model.ExtendedTableDataModel
org.richfaces.model.selection.Selection
org.richfaces.model.selection.SimpleSelection
这是以前的样子:
这是应该触发搜索逻辑的输入文本:
<h:inputText id="firmname" value="#{ExtendedTableBean.searchValue}">
<a4j:support ajaxSingle="true" eventsQueue="firmListUpdate"
reRender="resultsTable"
actionListener="#{ExtendedTableBean.searchForResults}" event="onkeyup" />
</h:inputText>
动作监听器应该更新列表。 这是inputData下方的extendedDataTable:
<rich:extendedDataTable tableState="#{ExtendedTableBean.tableState}" var="item"
id="resultsTable" value="#{ExtendedTableBean.dataModel}">
... <%-- I'm listing columns here --%>
</rich:extendedDataTable>
这是后端代码,我在其中使用数据模型处理:
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package com.beans;
import java.io.FileInputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.ConcurrentModificationException;
import java.util.List;
import java.util.Properties;
import java.util.concurrent.CopyOnWriteArrayList;
import javax.faces.context.FacesContext;
import javax.faces.event.ActionEvent;
import org.richfaces.model.DataProvider;
import org.richfaces.model.ExtendedTableDataModel;
public class ExtendedTableBean {
private String sortMode="single";
private ExtendedTableDataModel<ResultObject> dataModel;
//ResultObject is a simple pojo and getResultsPerValue is a method that
//read the data from the properties file, assigns it to this pojo, and
//adds a pojo to the list
private Object tableState;
private List<ResultObject> results = new CopyOnWriteArrayList<ResultObject>();
private List<ResultObject> selectedResults =
new CopyOnWriteArrayList<ResultObject>();
private String searchValue;
/**
* This is the action listener that the user triggers, by typing the search value
*/
public void searchForResults(ActionEvent e) {
synchronized(results) {
results.clear();
}
//I don't think it's necessary to clear results list all the time, but here
//I also make sure that we start searching if the value is at least 4
//characters long
if (this.searchValue.length() > 3) {
results.clear();
updateTableList();
} else {
results.clear();
}
dataModel = null; // to force the dataModel to be updated.
}
public List<ResultObject> getResultsPerValue(String searchValue) {
List<ResultObject> resultsList = new CopyOnWriteArrayList<ResultObject>();
//Logic for reading data from the properties file, populating ResultObject
//and adding it to the list
return resultsList;
}
/**
* This method updates a firm list, based on a search value
*/
public void updateTableList() {
try {
List<ResultObject> searchedResults = getResultsPerValue(searchValue);
//Once the results have been retrieved from the properties, empty
//current firm list and replace it with what was found.
synchronized(firms) {
firms.clear();
firms.addAll(searchedFirms);
}
} catch(Throwable xcpt) {
//Exception handling
}
}
/**
* This is a recursive method, that's used to constantly keep updating the
* table list.
*/
public synchronized ExtendedTableDataModel<ResultObject> getDataModel() {
try {
if (dataModel == null) {
dataModel = new ExtendedTableDataModel<ResultObject>(
new DataProvider<ResultObject>() {
public ResultObject getItemByKey(Object key) {
try {
for(ResultObject c : results) {
if (key.equals(getKey(c))){
return c;
}
}
} catch (Exception ex) {
//Exception handling
}
return null;
}
public List<ResultObject> getItemsByRange(
int firstRow, int endRow) {
return Collections.unmodifiableList(results.subList(firstRow, endRow));
}
public Object getKey(ResultObject item) {
return item.getResultName();
}
public int getRowCount() {
return results.size();
}
});
}
} catch (Exception ex) {
//Exception handling
}
return dataModel;
}
//Getters and setters
}
既然ExtendedTableDataModel和DataProvider类不再可用,我应该改用什么? RichFaces论坛声称,实际上没有任何东西,而开发人员在那里只能依靠自己(这意味着他们必须自己执行)。 有人还有其他想法或建议吗?
再次感谢您的所有帮助,对于一个冗长的问题,我们深表歉意。
您可以转换数据模型以扩展抽象的org.ajax4jsf.model.ExtendedDataModel
,它实际上是一个更健壮和高性能的数据模型,可与<rich:extendedDataTable/>
。 将现有模型粗略转换为下面的新模型(我决定使用现有的ExtendedDataModel<ResultObject>
作为基础数据源,而不是results
列表来演示转换):
public class MyDataModel<ResultObject> extends ExtendedDataModel<ResultObject>{
String currentKey; //current row in the model
Map<String, ResultObject> cachedResults = new HashMap<String, ResultObject>(); // a local cache of search/pagination results
List<String> cachedRowKeys; // a local cache of key values for cached items
int rowCount;
ExtendedTableDataModel<ResultObject> dataModel; // the underlying data source. can be anything
public void setRowKey(Object item){
this.currentKey = (ResultObject)item.getResultName();
}
public void walk(FacesContext context, DataVisitor visitor, Range range, Object argument) throws IOException {
int firstRow = ((SequenceRange)range).getFirstRow();
int numberOfRows = ((SequenceRange)range).getRows();
cachedRowkeys = new ArrayList<String>();
for (ResultObject result : dataModel.getItemsByRange(firstRow,numberOfRows)) {
cachedRowKeys.add(result.getResultName());
cachedResults.put(result.getResultName(), result); //populate cache. This is strongly advised as you'll see later.
visitor.process(context, result.getResultName(), argument);
}
}
}
public Object getRowData() {
if (currentKey==null) {
return null;
} else {
ResultObject selectedRowObject = cachedResults.get(currentKey); // return result from internal cache without making the trip to the database or other underlying datasource
if (selectedRowObject==null) { //if the desired row is not within the range of the cache
selectedRowObject = dataModel.getItemByKey(currentKey);
cachedResults.put(currentKey, selectedRowObject);
return selectedRowObject;
} else {
return selectedRowObject;
}
}
public int getRowCount(){
if(rowCount == 0){
rowCount = dataModel.getRowCount(); //cache row count
return rowCount;
}
return rowCount
}
这些是该课程中最重要的3种方法。 还有很多其他方法,基本上可以从不需要担心的旧版本中继承下来。 如果要将JSF状态保存到客户端,则可能对出于序列化目的的org.ajax4jsf.model.SerializableDataModel
感兴趣。 在这里查看示例。 这是一个老博客,但逻辑仍然适用。
与此无关,您当前的getRowData
实施在生产级应用程序中的表现将很差。 是否必须遍历每个元素以返回结果? 尝试更好的搜索算法。
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