org.primefaces.model.LazyDataModel Maven / Gradle / Ivy
/*
* The MIT License
*
* Copyright (c) 2009-2023 PrimeTek Informatics
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
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* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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package org.primefaces.model;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.model.ListDataModel;
import java.io.Serializable;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import javax.faces.convert.Converter;
import javax.faces.model.DataModelEvent;
import javax.faces.model.DataModelListener;
/**
* DataModel to deal with huge datasets with by lazy loading, page by page.
*
* @param The model class.
*/
public abstract class LazyDataModel extends ListDataModel implements SelectableDataModel, Serializable {
private static final long serialVersionUID = 1L;
private Converter converter;
private int rowCount;
private int pageSize;
// overwrite to restore serialization support; see #7699
private int rowIndex = -1;
private List data;
/**
* For serialization only
*/
public LazyDataModel() {
super();
}
/**
* This constructor allows to skip the implementation of {@link #getRowData(java.lang.String)} and
* {@link #getRowKey(java.lang.Object)}, when selection is used.
*
* @param converter The converter used to convert rowKey to rowData and vice versa.
*/
public LazyDataModel(Converter converter) {
super();
this.converter = converter;
}
/**
* Counts the all available data for the given filters.
*
* In case of SQL, this would execute a "SELECT COUNT ... WHERE ...".
*
* In case you dont use SQL and receive both rowCount
* and data within a single call, this method should just return 0.
* You must call {@link #recalculateFirst(int, int, int)} and {@link #setRowCount(int)}
* in your {@link #load(int, int, java.util.Map, java.util.Map)} method.
*
* @param filterBy a map with all filter information (only relevant for DataTable, not for eg DataView)
* @return the data count
*/
public abstract int count(Map filterBy);
/**
* Loads the data for the given parameters.
*
* @param first the first entry
* @param pageSize the page size
* @param sortBy a map with all sort information (only relevant for DataTable, not for eg DataView)
* @param filterBy a map with all filter information (only relevant for DataTable, not for eg DataView)
* @return the data
*/
public abstract List load(int first, int pageSize, Map sortBy, Map filterBy);
@Override
public T getRowData(String rowKey) {
if (converter != null) {
FacesContext context = FacesContext.getCurrentInstance();
return (T) converter.getAsObject(context, UIComponent.getCurrentComponent(context), rowKey);
}
throw new UnsupportedOperationException(
getMessage("Provide a Converter via constructor or implement getRowData(String rowKey) in %s"
+ ", when basic rowKey algorithm is not used [component=%s,view=%s]."));
}
public T getRowData(int rowIndex, Map sortBy, Map filterBy) {
List loaded = load(rowIndex, rowIndex + 1, sortBy, filterBy);
if (loaded == null || loaded.isEmpty()) {
return null;
}
return loaded.get(0);
}
/**
* Recalculates first, see #1921.
* Also see: {@link org.primefaces.component.api.UIPageableData#calculateFirst()}
*
* @param first the first param from the {@link #load(int, int, java.util.Map, java.util.Map)} method.
* @param pageSize the pageSize param from the {@link #load(int, int, java.util.Map, java.util.Map)} method.
* @param rowCount the new rowCount.
* @return the recalculated first.
*/
protected int recalculateFirst(int first, int pageSize, int rowCount) {
if (rowCount > 0 && first >= rowCount) {
int numberOfPages = (int) Math.ceil(rowCount * 1d / pageSize);
first = Math.max((numberOfPages - 1) * pageSize, 0);
}
return first;
}
@Override
public String getRowKey(T object) {
if (converter != null) {
FacesContext context = FacesContext.getCurrentInstance();
return converter.getAsString(context, UIComponent.getCurrentComponent(context), object);
}
throw new UnsupportedOperationException(
getMessage("Provide a Converter via constructor or implement getRowKey(T object) in %s"
+ ", when basic rowKey algorithm is not used [component=%s,view=%s]."));
}
protected String getMessage(String msg) {
FacesContext facesContext = FacesContext.getCurrentInstance();
String viewId = facesContext.getViewRoot().getViewId();
UIComponent component = UIComponent.getCurrentComponent(facesContext);
String clientId = component == null ? "" : component.getClientId(facesContext);
return String.format(msg, getClass().getName(), clientId, viewId);
}
@Override
public boolean isRowAvailable() {
if (data == null) {
return false;
}
return rowIndex >= 0 && rowIndex < data.size();
}
@Override
public T getRowData() {
return data.get(rowIndex);
}
@Override
public List getWrappedData() {
return data;
}
@Override
public void setWrappedData(Object list) {
this.data = (List) list;
}
@Override
public int getRowIndex() {
return this.rowIndex;
}
@Override
public void setRowIndex(int rowIndex) {
int oldIndex = this.rowIndex;
if (rowIndex == -1) {
this.rowIndex = -1;
}
else if (pageSize > 0) {
this.rowIndex = (rowIndex % pageSize);
}
else {
this.rowIndex = rowIndex;
}
if (data == null) {
return;
}
DataModelListener[] listeners = getDataModelListeners();
if (listeners != null && oldIndex != this.rowIndex) {
Object rowData = null;
if (isRowAvailable()) {
rowData = getRowData();
}
DataModelEvent dataModelEvent = new DataModelEvent(this, rowIndex, rowData);
for (int i = 0; i < listeners.length; i++) {
listeners[i].rowSelected(dataModelEvent);
}
}
}
@Override
public Iterator iterator() {
return new LazyDataModelIterator<>(this);
}
public Iterator iterator(Map sortBy, Map filterBy) {
return new LazyDataModelIterator<>(this, sortBy, filterBy);
}
@Override
public int getRowCount() {
return rowCount;
}
public int getPageSize() {
return pageSize;
}
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
public void setRowCount(int rowCount) {
this.rowCount = rowCount;
}
public Converter getConverter() {
return converter;
}
public void setConverter(Converter converter) {
this.converter = converter;
}
}
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