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

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Here is the source code for org.apache.wicket.extensions.ajax.markup.html.autocomplete.AbstractAutoCompleteRenderer.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 org.apache.wicket.request.Response;
import org.apache.wicket.util.string.Strings;

/**
 * A renderer that abstracts autoassist specific details and allows subclasses to only render the
 * visual part of the assist instead of having to also render the necessary autoassist javascript
 * hooks.
 * 
 * @param <T>
 * 
 * @since 1.2
 * 
 * @author Igor Vaynberg (ivaynberg)
 */
public abstract class AbstractAutoCompleteRenderer<T> implements IAutoCompleteRenderer<T> {
    private static final long serialVersionUID = 1L;

    @Override
    public void render(final T object, final Response response, final String criteria) {
        String textValue = getTextValue(object);
        if (textValue == null) {
            throw new IllegalStateException(
                    "A call to textValue(Object) returned an illegal value: null for object: " + object.toString());
        }
        textValue = Strings.escapeMarkup(textValue).toString();

        response.write("<li textvalue=\"" + textValue + "\"");
        final CharSequence handler = getOnSelectJavaScriptExpression(object);
        if (handler != null) {
            response.write(" onselect=\"" + handler + '"');
        }
        response.write(">");
        renderChoice(object, response, criteria);
        response.write("</li>");
    }

    @Override
    public void renderHeader(final Response response) {
        response.write("<ul>");
    }

    @Override
    public void renderFooter(final Response response, int count) {
        response.write("</ul>");
    }

    /**
     * Render the visual portion of the assist. Usually the html representing the assist choice
     * object is written out to the response use {@link Response#write(CharSequence)}
     * 
     * @param object
     *            current assist choice
     * @param response
     * @param criteria
     */
    protected abstract void renderChoice(T object, Response response, String criteria);

    /**
     * Retrieves the text value that will be set on the textbox if this assist is selected
     * 
     * @param object
     *            assist choice object
     * @return the text value that will be set on the textbox if this assist is selected
     */
    protected abstract String getTextValue(T object);

    /**
     * Allows the execution of a custom javascript expression when an item is selected in the
     * autocompleter popup (either by clicking on it or hitting enter on the current selection).
     * <p/>
     * The javascript to execute must be a javascript expression that will be processed using
     * javascript's eval(). The function should return the textvalue to copy it into the
     * corresponding form input field (the default behavior).
     * 
     * the current text value will be in variable 'input'.
     * 
     * If the function returns <code>null</code> the chosen text value will be ignored.
     * <p/>
     * example 1:
     * 
     * <pre>
     * protected CharSequence getOnSelectJavaScript(Address address)
     * {
     *    final StringBuilder js = new StringBuilder();
     *    js.append(&quot;wicketGet('street').value ='&quot; + address.getStreet() + &quot;';&quot;);
     *    js.append(&quot;wicketGet('zipcode').value ='&quot; + address.getZipCode() + &quot;';&quot;);
     *    js.append(&quot;wicketGet('city').value ='&quot; + address.getCity() + &quot;';&quot;);
     *    js.append(&quot;input&quot;); // &lt;-- do not use return statement here!
     *    return js.toString();
     * }
     * </pre>
     * 
     * example 2:
     * 
     * <pre>
     * protected CharSequence getOnSelectJavaScript(Currency currency)
     * {
     *    final StringBuilder js = new StringBuilder();
     *    js.append(&quot;val rate = ajaxGetExchangeRateForCurrency(currencySymbol);&quot;);
     *    js.append(&quot;if(rate == null) alert('exchange rate service currently not available');&quot;);
     *    js.append(&quot;rate&quot;);
     *    return js.toString();
     * }
     * </pre>
     * 
     * Then the autocompleter popup will be closed.
     * 
     * @param item
     *            the autocomplete item to get a custom javascript expression for
     * @return javascript to execute on selection or <code>null</code> if default behavior is
     *         intented
     */
    protected CharSequence getOnSelectJavaScriptExpression(final T item) {
        return null;
    }
}