com.vaynberg.wicket.select2.AbstractSelect2Choice Maven / Gradle / Ivy

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/*
 * Copyright 2012 Igor Vaynberg
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this work except in compliance with
 * the License. You may obtain a copy of the License in the LICENSE file, or 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.vaynberg.wicket.select2;

import java.io.IOException;
import java.io.OutputStreamWriter;

import org.apache.wicket.IRequestListener;
import org.apache.wicket.model.IModel;
import org.apache.wicket.request.IRequestParameters;
import org.apache.wicket.request.Request;
import org.apache.wicket.request.http.WebResponse;
import org.json.JSONException;
import org.json.JSONWriter;

/**
 * Base class for Select2 components
 *
 * @param  type of choice object
 * @param  type of model object
 * @author igor
 */
abstract class AbstractSelect2Choice extends Select2ChoiceBaseComponent implements IRequestListener {

    private ChoiceProvider provider;

    /**
     * Constructor
     *
     * @param id component id
     */
    public AbstractSelect2Choice(String id) {
        this(id, null, null);
    }

    /**
     * Constructor
     *
     * @param id    component id
     * @param model component model
     */
    public AbstractSelect2Choice(String id, IModel model) {
        this(id, model, null);
    }

    /**
     * Constructor.
     *
     * @param id       component id
     * @param provider choice provider
     */
    public AbstractSelect2Choice(String id, ChoiceProvider provider) {
        this(id, null, provider);
    }

    /**
     * Constructor
     *
     * @param id       component id
     * @param model    component model
     * @param provider choice provider
     */
    public AbstractSelect2Choice(String id, IModel model, ChoiceProvider provider) {
        super(id, model);
        this.provider = provider;
    }


    /**
     * Sets the choice provider
     *
     * @param provider
     */
    public final void setProvider(ChoiceProvider provider) {
        this.provider = provider;
    }

    /**
     * @return choice provider
     */
    public final ChoiceProvider getProvider() {
        if (provider == null) {
            throw new IllegalStateException("Select2 choice component: " + getId()
                    + " does not have a ChoiceProvider set");
        }
        return provider;
    }

    @Override
    protected void onConfigure() {
        super.onConfigure();

        getSettings().getAjax().setUrl(urlForListener(null));
    }


    @Override
    public void onRequest() {

        // this is the callback that retrieves matching choices used to populate the dropdown

        Request request = getRequestCycle().getRequest();
        IRequestParameters params = request.getRequestParameters();

        // retrieve choices matching the search term

        String term = params.getParameterValue("term").toOptionalString();

        int page = params.getParameterValue("page").toInt(1);
        // select2 uses 1-based paging, but in wicket world we are used to
        // 0-based
        page -= 1;

        Response response = new Response();
        getProvider().query(term, page, response);

        // jsonize and write out the choices to the response

        WebResponse webResponse = (WebResponse) getRequestCycle().getResponse();
        webResponse.setContentType("application/json");

        OutputStreamWriter out = new OutputStreamWriter(webResponse.getOutputStream(), getRequest().getCharset());
        JSONWriter json = new JSONWriter(out);

        try {
            json.object().key("results").array();
            addValues(json, response);
            json.endArray().key("more").value(response.getHasMore()).endObject();
        } catch (JSONException e) {
            throw new RuntimeException("Could not write Json response", e);
        }

        try {
            out.flush();
        } catch (IOException e) {
            throw new RuntimeException("Could not write Json to servlet response", e);
        }
    }

    @Override
    public boolean rendersPage() {
        return false;
    }

    @Override
    protected void onDetach() {
        getProvider().detach();
        super.onDetach();
    }

    @Override
    protected boolean getStatelessHint() {
        return false;
    }


    protected void addValues(final JSONWriter json, final Iterable response) throws JSONException {
        for (T item : response) {
            json.object();
            getProvider().toJson(item, json);
            json.endObject();
        }
    }
}