org.apache.wicket.extensions.ajax.markup.html.autocomplete.AutoCompleteBehavior.java Source code

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Here is the source code for org.apache.wicket.extensions.ajax.markup.html.autocomplete.AutoCompleteBehavior.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 org.apache.wicket.extensions.ajax.markup.html.autocomplete;

import java.util.Iterator;

import org.apache.wicket.Application;
import org.apache.wicket.Component;
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.lang.Args;

/**
 * This behavior builds on top of {@link AbstractAutoCompleteBehavior} by introducing the concept of
 * a {@link IAutoCompleteRenderer} to make response writing easier.
 * 
 * @param <T>
 * 
 * @see IAutoCompleteRenderer
 * 
 * @since 1.2
 * 
 * @author Igor Vaynberg (ivaynberg)
 * @author Janne Hietam&auml;ki (jannehietamaki)
 */
public abstract class AutoCompleteBehavior<T> extends AbstractAutoCompleteBehavior {
    private static final long serialVersionUID = 1L;

    private final IAutoCompleteRenderer<T> renderer;

    /**
     * Constructor
     * 
     * @param renderer
     *            renderer that will be used to generate output
     */
    public AutoCompleteBehavior(final IAutoCompleteRenderer<T> renderer) {
        this(renderer, false);
    }

    /**
     * Constructor
     * 
     * @param renderer
     *            renderer that will be used to generate output
     * @param preselect
     *            highlight/preselect the first item in the autocomplete list automatically
     */
    public AutoCompleteBehavior(final IAutoCompleteRenderer<T> renderer, final boolean preselect) {
        this(renderer, new AutoCompleteSettings().setPreselect(preselect));
    }

    /**
     * Constructor
     * 
     * @param renderer
     *            renderer that will be used to generate output
     * @param settings
     *            settings for the autocomplete list
     */
    public AutoCompleteBehavior(final IAutoCompleteRenderer<T> renderer, final AutoCompleteSettings settings) {
        super(settings);

        this.renderer = Args.notNull(renderer, "renderer");
    }

    @Override
    protected final void onRequest(final String val, final RequestCycle requestCycle) {
        IRequestHandler target = new IRequestHandler() {
            @Override
            public void respond(final IRequestCycle requestCycle) {
                WebResponse r = (WebResponse) requestCycle.getResponse();

                // Determine encoding
                final String encoding = Application.get().getRequestCycleSettings().getResponseRequestEncoding();

                r.setContentType("text/xml; charset=" + encoding);
                r.disableCaching();

                Iterator<T> comps = getChoices(val);
                int count = 0;
                renderer.renderHeader(r);
                while (comps.hasNext()) {
                    final T comp = comps.next();
                    renderer.render(comp, r, val);
                    count += 1;
                }
                renderer.renderFooter(r, count);
            }
        };

        requestCycle.scheduleRequestHandlerAfterCurrent(target);
    }

    /**
     * Callback method that should return an iterator over all possible choice objects. These
     * objects will be passed to the renderer to generate output. Usually it is enough to return an
     * iterator over strings.
     * 
     * @param input
     *            current input
     * @return iterator over all possible choice objects
     */
    protected abstract Iterator<T> getChoices(String input);

    @Override
    public void detach(Component component) {
        renderer.detach();
    }
}