com.googlecode.wicket.jquery.ui.kendo.datatable.DataSourceBehavior.java Source code

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Here is the source code for com.googlecode.wicket.jquery.ui.kendo.datatable.DataSourceBehavior.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 com.googlecode.wicket.jquery.ui.kendo.datatable;

import java.util.Iterator;
import java.util.List;

import org.apache.wicket.Application;
import org.apache.wicket.ajax.AbstractDefaultAjaxBehavior;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.ajax.json.JSONException;
import org.apache.wicket.ajax.json.JSONStringer;
import org.apache.wicket.markup.repeater.data.IDataProvider;
import org.apache.wicket.request.IRequestCycle;
import org.apache.wicket.request.IRequestHandler;
import org.apache.wicket.request.cycle.RequestCycle;
import org.apache.wicket.request.http.WebResponse;
import org.apache.wicket.util.convert.ConversionException;

import com.googlecode.wicket.jquery.core.Options;
import com.googlecode.wicket.jquery.ui.kendo.datatable.column.IColumn;
import com.googlecode.wicket.jquery.ui.kendo.datatable.column.PropertyColumn;

/**
 * Provides the {@link DataTable} data source {@link AbstractDefaultAjaxBehavior}
 *
 * @param <T> the type of the model object
 * @author Sebastien Briquet - sebfz1
 */
class DataSourceBehavior<T> extends AbstractDefaultAjaxBehavior {
    private static final long serialVersionUID = 1L;

    private final IDataProvider<T> provider;
    private final List<? extends IColumn<T>> columns;

    /**
     * Constructor
     * @param columns the list of {@link IColumn}
     * @param provider the {@link IDataProvider}
     * @param rows the number of rows per page to be displayed
     */
    public DataSourceBehavior(final List<? extends IColumn<T>> columns, final IDataProvider<T> provider,
            final long rows) {
        this.columns = columns;
        this.provider = provider;
    }

    @Override
    protected void respond(AjaxRequestTarget target) {
        final RequestCycle requestCycle = RequestCycle.get();
        final int first = requestCycle.getRequest().getQueryParameters().getParameterValue("skip").toInt(0);
        final int count = requestCycle.getRequest().getQueryParameters().getParameterValue("take").toInt(0);

        final IRequestHandler handler = this.newRequestHandler(first, count);
        requestCycle.scheduleRequestHandlerAfterCurrent(handler);
    }

    /**
     * Gets the new {@link IRequestHandler} that will respond the data in a json format
     *
     * @param first the first row number
     * @param count the count of rows
     * @return a new {@link IRequestHandler}
     */
    private IRequestHandler newRequestHandler(final int first, final int count) {
        return new IRequestHandler() {
            @Override
            public void respond(final IRequestCycle requestCycle) {
                WebResponse response = (WebResponse) requestCycle.getResponse();

                final String encoding = Application.get().getRequestCycleSettings().getResponseRequestEncoding();
                response.setContentType("text/json; charset=" + encoding);
                response.disableCaching();

                final long size = provider.size();
                final Iterator<? extends T> iterator = provider.iterator(first, count);

                // builds JSON result //
                StringBuilder builder = new StringBuilder();

                builder.append("{ ");
                builder.append(Options.QUOTE).append("__count").append(Options.QUOTE).append(": ").append(size)
                        .append(", ");
                builder.append(Options.QUOTE).append("results").append(Options.QUOTE).append(": ");
                builder.append("[ ");

                for (int index = 0; iterator.hasNext(); index++) {
                    if (index > 0) {
                        builder.append(", ");
                    }

                    builder.append(DataSourceBehavior.this.newJsonRow(iterator.next()));
                }

                builder.append(" ] }");

                response.write(builder);
            }

            @Override
            public void detach(final IRequestCycle requestCycle) {
            }
        };
    }

    /**
     * Gets a new JSON object from the bean
     * @param bean T object
     * @return a new JSON object
     */
    protected String newJsonRow(T bean) {
        JSONStringer stringer = new JSONStringer();

        try {
            stringer.object();

            for (IColumn<T> column : this.columns) {
                if (column instanceof PropertyColumn<?>) {
                    PropertyColumn<T> pc = (PropertyColumn<T>) column;
                    stringer.key(pc.getField()).value(pc.getValue(bean));
                }
            }

            stringer.endObject();
        } catch (JSONException e) {
            throw new ConversionException(e);
        }

        return stringer.toString();
    }
}