modelutils.java

分页查询控件 分页查询控件

/*
 * Copyright 2004 original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.extremecomponents.base;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import javax.servlet.ServletRequest;

import org.apache.commons.lang.StringUtils;
import org.extremecomponents.table.bean.Table;
import org.extremecomponents.table.core.ParameterRegistry;
import org.extremecomponents.table.handler.ExportHandler;

/**
 * Helpful utilities for the Table and Tree Model
 * 
 * @author Jeff Johnston
 */
public class ModelUtils {
    private ModelUtils() {
    }

    /**
     * The page that is going to be displayed.
     * 
     * @param request ServletRequest
     * @param collection TableTag collection attribute
     * @return
     */
    public static int getPage(ServletRequest request, String collection) {
    	String pagination = request.getParameter(collection + "_" + ParameterRegistry.PAGE);

    	int page = 1;

        if (!StringUtils.isEmpty(pagination)) {
            page = Integer.parseInt(pagination);
        }
        
        return page;
    }
    
    /**
     * The column being sorted, if any.
     * 
     * @param request ServletRequest
     * @param collection TableTag collection attribute
     * @return
     */
    public static Map getSort(ServletRequest request, String collection) {
    	return getSortedOrFilteredParameters(request, collection, ParameterRegistry.SORT);
    }

    /**
     * The columns being filtered, if any.
     * 
     * @param request ServletRequest
     * @param collection TableTag collection attribute
     * @return
     */
    public static Map getFilters(ServletRequest request, String collection) {
    	return getSortedOrFilteredParameters(request, collection, ParameterRegistry.FILTER);
    }
    
    /**
     * Because the rowsDisplayed is a table attribute the only time the value
     * is passed is when the rowsDisplayed is changed (usually through Rows Displayed dropdown).
     * If the rowsDisplayed is changed then will return what that change is. 
     * If the value is not changed then will return null. Use the 4 parameter 
     * getRowsDisplayed() method to abstract out how to find the amount 
     * of rows that should be displayed.
     * 
     * @param request ServletRequest
     * @param collection TableTag collection attribute
     * @return
     */
    private static String getRowsDisplayed(ServletRequest request, String collection)
    {
        String rowsDisplayed = request.getParameter(collection + "_" + ParameterRegistry.ROWS_DISPLAYED);
        if (StringUtils.isNotEmpty(rowsDisplayed)) {
            return rowsDisplayed;
        }
        
        return null;
    }
    
    /**
     * Because the rowsDisplayed is a table attribute the only time the value
     * is passed is when the rowsDisplayed is changed (usually through Rows Displayed dropdown).
     * This is a convience method to abstract out the rules to find out the amount of rows 
     * that should be displayed.
     * 
     * @param request ServletRequest
     * @param collection TableTag collection attribute
     * @param defaultRowsDisplayed TableTag rowsDisplayed attribute
     * @param totalRows Total possible for result set
     * @return
     */
    public static int getRowsDisplayed(ServletRequest request, String collection, int defaultRowsDisplayed, int totalRows) {
        int result = -1;
        
        String rowsDisplayed = getRowsDisplayed(request, collection);
        if (StringUtils.isNotBlank(rowsDisplayed)) {
            result = Integer.parseInt(rowsDisplayed);
        }
        
        if (result == -1) {
            result = defaultRowsDisplayed;
        }

        if (result == 0) {
            result = totalRows;
        }
        
        return result;
    }

    /**
     * Get the collection of properties and values that was sorted or filtered.
     * 
     * @param parameter Either the ParameterRegistry.FILTER or ParameterRegistry.SORT
     * @return Map of property/value pairs
     */
    private static Map getSortedOrFilteredParameters(ServletRequest request, String collection, String parameter) {
        Map subset = null;

        Set set = request.getParameterMap().keySet();

        for (Iterator iter = set.iterator(); iter.hasNext();) {
            if (subset == null) {
                subset = new HashMap();
            }
            
            String key = (String) iter.next();
            String find =  collection + "_" + parameter;
            
            if (key.startsWith(find)) {
                String value = (String) request.getParameter(key);
                if (StringUtils.isNotBlank(value)) {
                    subset.put(StringUtils.substringAfter(key, find), value);
                }
            }
        }

        return subset;
    }
    
    public static boolean isExportMode(ServletRequest request) {
        String table = request.getParameter(Table.EXTREME_TABLE);

        String exportName = null;

        if (StringUtils.isNotBlank(table)) {
            exportName = findExportName(request);
        }

        return StringUtils.isNotBlank(exportName);
    }

    public static String findInvokeExport(ServletRequest request) {
        String table = request.getParameter(Table.EXTREME_TABLE);

        if (StringUtils.isNotBlank(table)) {
            return request.getParameter(table + ParameterRegistry.EXPORT);
        }

        return null;
    }

    public static String findExportName(ServletRequest request) {
        String table = request.getParameter(Table.EXTREME_TABLE);

        if (StringUtils.isNotBlank(table)) {
            return request.getParameter(table + ExportHandler.EXPORT_NAME);
        }

        return null;
    }
}