basemodel.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.core;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.jsp.PageContext;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.extremecomponents.table.callback.RetrieveRowsCallback;
import org.extremecomponents.table.cell.Cell;
import org.extremecomponents.table.handler.ColumnHandler;
import org.extremecomponents.table.handler.ExportHandler;
import org.extremecomponents.table.handler.FormHandler;
import org.extremecomponents.table.handler.RowHandler;
import org.extremecomponents.table.handler.TableHandler;
import org.extremecomponents.table.handler.TreeHandler;
import org.extremecomponents.table.handler.ViewHandler;
import org.extremecomponents.table.limit.Limit;
import org.extremecomponents.table.limit.ModelLimitFactory;
import org.extremecomponents.util.ExceptionUtils;

/**
 * @author Paul Horn
 */
public abstract class BaseModel {
    private static Log logger = LogFactory.getLog(BaseModel.class);

    private PageContext pageContext;

    protected BaseProperties properties;
    protected TableHandler tableHandler;

    private ParameterRegistry registry = new ParameterRegistry(this);
    private TableResourceBundle resourceBundle = new TableResourceBundle(this);
    private ExportHandler exportHandler = new ExportHandler(this);
    private FormHandler formHandler = new FormHandler();
    private RowHandler rowHandler = new RowHandler(this);
    private ColumnHandler columnHandler = new ColumnHandler(this);
    private ViewHandler viewHandler = new ViewHandler(this);

    // model objects
    private Limit limit;
    private Object collectionOfBeans;
    private Object currentCollectionBean;

    // cache out some objects
    private Map cellCache = new HashMap();
    private Map callbacks = new HashMap();
    private AutoGenerateColumns autoGenerateColumns;

    public BaseModel(PageContext pageContext) {
        this.pageContext = pageContext;
    }

    /**
     * Access to the Servlet pageContext()
     */
    public PageContext getPageContext() {
        return pageContext;
    }

    /**
     * A simple implementation of a cache for the Cell definitions.
     */
    public Cell getCachedCell(Class classDefinition) {
        Cell cell = (Cell) cellCache.get(classDefinition);

        if (cell == null) {
            try {
                Object object = classDefinition.newInstance();
                cell = (Cell) object;
                cellCache.put(classDefinition, cell);
                if (logger.isDebugEnabled()) {
                    logger.debug("Cache the Cell [" + classDefinition + "]");
                }
            } catch (Exception e) {
                logger.error("BaseModel.getCachedCell() " + ExceptionUtils.formatStackTrace(e));
            }
        }

        return cell;
    }

    /**
     * Return the proper callback. The trick here is that could return the same
     * class for different callbacks. This is a feature so that do not have to
     * make different classes for each individual callback.
     */
    public Object getCallback(String callbackClassName)
            throws Exception {
        Object result = callbacks.get(callbackClassName);
        if (result != null) {
            return result;
        }

        Class classDefinition = Class.forName(callbackClassName);
        result = classDefinition.newInstance();
        callbacks.put(callbackClassName, result);

        return result;
    }

    public Map getCellCache() {
        return cellCache;
    }

    public ParameterRegistry getRegistry() {
        return registry;
    }

    public ColumnHandler getColumnHandler() {
        return columnHandler;
    }

    public TableHandler getTableHandler() {
        return tableHandler;
    }

    public TreeHandler getTreeHandler() {
        return (TreeHandler) tableHandler;
    }

    public RowHandler getRowHandler() {
        return rowHandler;
    }

    public ExportHandler getExportHandler() {
        return exportHandler;
    }

    public FormHandler getFormHandler() {
        return formHandler;
    }

    public BaseProperties getProperties() {
        return properties;
    }

    public TableResourceBundle getResourceBundle() {
        return resourceBundle;
    }

    public ViewHandler getViewHandler() {
        return viewHandler;
    }

    public List getCollectionOfBeans() {
        return (List) collectionOfBeans;
    }

    private void setCollectionOfBeans(Collection collectionOfBeans)
            throws Exception {
        this.collectionOfBeans = collectionOfBeans;

        if (collectionOfBeans == null) {
            String message = "The collection sent into the eXtremeTable is NULL.";
            logger.error(message);
            throw new Exception(message);
        }
    }

    public Object getCurrentCollectionBean() {
        return currentCollectionBean;
    }

    public void setCurrentCollectionBean(Object currentCollectionBean) {
        this.currentCollectionBean = currentCollectionBean;
    }

    public Limit getLimit() {
        return limit;
    }

    public AutoGenerateColumns getAutoGenerateColumns() {
        return autoGenerateColumns;
    }

    public void setAutoGenerateColumns(AutoGenerateColumns autoGenerateColumns) {
        this.autoGenerateColumns = autoGenerateColumns;
    }

    public Collection execute()
            throws Exception {
        this.limit = ModelLimitFactory.createInstanceOfLimit(this);
        ModelLimitFactory.setLimitFilterAndSortAttr(limit);

        RetrieveRowsCallback retrieveRowsCallback = (RetrieveRowsCallback) getCallback(getTableHandler().getTable()
                .getRetrieveRowsCallback());

        Collection rows = retrieveRowsCallback.retrieveRows(this);

        rows = new ArrayList(rows); // copy for thread safety

        setCollectionOfBeans(rows);

        rows = executeInternal(rows, limit);

        viewHandler.setView();

        return rows;
    }

    public void destroy() {
        properties = null;
        resourceBundle = null;
        tableHandler.destroy();
        tableHandler = null;
        exportHandler.destroy();
        exportHandler = null;
        formHandler.destroy();
        formHandler = null;
        columnHandler.destroy();
        columnHandler = null;
        rowHandler.destroy();
        rowHandler = null;
        cellCache.clear();
        cellCache = null;
        callbacks.clear();
        callbacks = null;
        limit = null;
        collectionOfBeans = null;
        currentCollectionBean = null;
        autoGenerateColumns = null;
    }

    abstract Collection executeInternal(Collection rows, Limit limit)
            throws Exception;
}