plum.mybatis.PagingParametersFinder.java Source code

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Here is the source code for plum.mybatis.PagingParametersFinder.java

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/*
 * Copyright (c) 2012-2013, Poplar Yfyang ?? (poplar1123@gmail.com).
 *
 * 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 plum.mybatis;

import java.lang.reflect.Array;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.beanutils.BeanMap;
import org.apache.commons.lang3.StringUtils;
import plum.utils.page.PageQuery;
import plum.utils.reflex.Classs;

/**
 * <p>
 * Paging <code>PaginationCriteria</code> finds.
 * </p>
 *
 * @author poplar.yfyang
 * @version 1.0 2012-12-09 7:22 PM
 * @see PageQuery
 * @since JDK 1.5
 */
public final class PagingParametersFinder {

    /** The search parameters by use of interim storage of results. */
    private final Map<Object, String> search_map = new HashMap<Object, String>();

    /** private constructor */
    private PagingParametersFinder() {
    }

    /**
     * get pagingParametersFinder instance object.
     *
     * @return pagingParametersFinder.
     */
    public static PagingParametersFinder getInstance() {
        return App.pagingParametersFinder;
    }

    /**
     * from the formulation of the objects found in the paging parameters object.
     *
     * @param object object.
     * @return paging parameters.
     */
    public PageQuery findCriteria(Object object) {
        if (object == null) {
            return null;
        }
        try {
            return findCriteriaFromObject(object);
        } finally {
            //cleanup query the value of the temporary Map.
            search_map.clear();
        }
    }

    /**
     * In the object to find whether contains <code>PaginationCriteria</code> objects.
     *
     * @param object parameter object.
     * @return PaginationCriteria
     */
    private PageQuery findCriteriaFromObject(Object object) {

        //???NULL
        if (search_map.containsKey(object)) {
            return null;
        }
        //object class
        Class<?> obj_class = object.getClass();
        PageQuery pc;
        //primitive
        if (Classs.isPrimitiveType(obj_class)) {
            pc = null;
        } else if (obj_class.isAssignableFrom(PageQuery.class)) {
            pc = (PageQuery) object;
        } else if (object instanceof Map) {
            pc = findCriteriaFromMap((Map) object);
        } else if (object instanceof Collection) {
            pc = findCriteriaFromCollection((Collection) object);
        } else if (obj_class.isArray()) {
            pc = findCriteriaFromArray(object);
        } else {
            BeanMap map = new BeanMap(object);
            return findCriteriaFromMap(map);
        }

        search_map.put(object, StringUtils.EMPTY);
        return pc;
    }

    /**
     * In the array to find whether it contains the <code>PaginationCriteria</code> object.
     *
     * @param array the array.
     * @return PageQuery
     */
    private PageQuery findCriteriaFromArray(Object array) {
        if (search_map.containsKey(array)) {
            return null;
        }

        for (int i = 0; i < Array.getLength(array); i++) {
            Object object = Array.get(array, i);
            PageQuery pc = findCriteriaFromObject(object);
            if (pc != null) {
                search_map.put(array, StringUtils.EMPTY);
                return pc;
            }
        }
        search_map.put(array, StringUtils.EMPTY);
        return null;
    }

    /**
     * In the Collection to find whether contains <code>PaginationCriteria</code> objects.
     *
     * @param collection parameter collection.
     * @return PageQuery
     */
    private PageQuery findCriteriaFromCollection(Collection collection) {
        if (search_map.containsKey(collection)) {
            return null;
        }

        for (Object e : collection) {
            PageQuery pc = findCriteriaFromObject(e);
            if (pc != null) {
                search_map.put(collection, StringUtils.EMPTY);
                return pc;
            }
        }

        search_map.put(collection, StringUtils.EMPTY);
        return null;
    }

    /**
     * In the Map to find whether contains <code>PaginationCriteria</code> objects.
     *
     * @param map parameter map.
     * @return PaginationCriteria
     */
    private PageQuery findCriteriaFromMap(Map map) {
        if (search_map.containsKey(map)) {
            return null;
        }

        for (Object value : map.values()) {
            PageQuery pc = findCriteriaFromObject(value);
            if (pc != null) {
                search_map.put(map, StringUtils.EMPTY);
                return pc;
            }
        }

        search_map.put(map, StringUtils.EMPTY);
        return null;
    }

    /** Single cased of associated object. */
    private static class App {
        /** Single pagingParametersFinder. */
        protected static PagingParametersFinder pagingParametersFinder = new PagingParametersFinder();
    }
}