limitfactory.java

exTreme taglib的使用

/*
 * 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.table.limit;

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.core.TableConstants;

/**
 * @author Jeff Johnston
 */
public final class LimitFactory {
    public static Limit createInstanceOfLimit(ServletRequest request, String tableId) {
        return new RequestLimit(request, tableId);
    }

    public static void setLimitFilterAndSortAttr(Limit limit) {
        limit.setFilterSet(getFilterSet((RequestLimit)limit));
        limit.setSort(getSort((RequestLimit)limit));
    }
    
    public static void setLimitPageAndRowAttr(Limit limit, int defaultRowsDisplayed, int totalRows) {
        int currentRowsDisplayed = resolveCurrentRowsDisplayed((RequestLimit)limit, defaultRowsDisplayed);

        int page = getPage((RequestLimit)limit);

        int rowStart = (page - 1) * currentRowsDisplayed;

        int rowEnd = rowStart + currentRowsDisplayed;

        if (rowEnd > totalRows) {
            rowEnd = totalRows;
        }

        limit.setPage(page);
        limit.setCurrentRowsDisplayed(currentRowsDisplayed);
        limit.setTotalRows(totalRows);
        limit.setRowStart(rowStart);
        limit.setRowEnd(rowEnd);
    }

    private static int resolveCurrentRowsDisplayed(RequestLimit limit, int defaultRowsDisplayed) {
        String currentRowsDisplayed = limit.getRequest().getParameter(limit.getTableId() + "_" + TableConstants.CURRENT_ROWS_DISPLAYED);
        if (StringUtils.isNotEmpty(currentRowsDisplayed)) {
            return Integer.parseInt(currentRowsDisplayed);
        }

        return defaultRowsDisplayed;
    }

    private static int getPage(RequestLimit limit) {
        String pagination = limit.getRequest().getParameter(limit.getTableId() + "_" + TableConstants.PAGE);
        if (!StringUtils.isEmpty(pagination)) {
            return Integer.parseInt(pagination);
        }

        return 1;
    }

    private static Sort getSort(RequestLimit limit) {
        Map sortedParameters = getSortedOrFilteredParameters(limit, TableConstants.SORT);
        return LimitFactoryUtils.getSort(sortedParameters);
    }

    private static FilterSet getFilterSet(RequestLimit limit) {
        Map filteredParameters = getSortedOrFilteredParameters(limit, TableConstants.FILTER);
        return LimitFactoryUtils.getFilterSet(filteredParameters);
    }

    private static Map getSortedOrFilteredParameters(RequestLimit limit, String parameter) {
        Map subset = new HashMap();

        Set set = limit.getRequest().getParameterMap().keySet();
        String find = limit.getTableId() + "_" + parameter;

        for (Iterator iter = set.iterator(); iter.hasNext();) {
            String key = (String) iter.next();
            if (key.startsWith(find)) {
                String value = limit.getRequest().getParameter(key);
                if (StringUtils.isNotBlank(value)) {
                    subset.put(StringUtils.substringAfter(key, find), value);
                }
            }
        }

        return subset;
    }
}