org.apache.wicket.markup.html.form.EnumChoiceRenderer.java Source code

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Here is the source code for org.apache.wicket.markup.html.form.EnumChoiceRenderer.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.markup.html.form;

import org.apache.wicket.Application;
import org.apache.wicket.Component;
import org.apache.wicket.util.lang.Classes;

/**
 * {@link IChoiceRenderer} implementation that makes it easy to work with java 5 enums. This
 * renderer will attempt to lookup strings used for the display value using a localizer of a given
 * component. If the component is not specified, the global instance of localizer will be used for
 * lookups.
 * <p>
 * display value resource key format: {@code <enum.getSimpleClassName()>.<enum.name()>}
 * </p>
 * <p>
 * id value format: {@code <enum.name()>}
 * </p>
 * 
 * @author igor.vaynberg
 * 
 * @param <T>
 */
public class EnumChoiceRenderer<T extends Enum<T>> extends ChoiceRenderer<T> {

    private static final long serialVersionUID = 1L;

    /**
     * component used to resolve i18n resources for this renderer.
     */
    private final Component resourceSource;

    /**
     * Constructor that creates the choice renderer that will use global instance of localizer to
     * resolve resource keys.
     */
    public EnumChoiceRenderer() {
        this(null);
    }

    /**
     * Constructor
     * 
     * @param resourceSource
     */
    public EnumChoiceRenderer(Component resourceSource) {
        this.resourceSource = resourceSource;
    }

    /** {@inheritDoc} */
    @Override
    public Object getDisplayValue(T object) {
        final String value;

        String key = resourceKey(object);

        if (resourceSource != null) {
            value = resourceSource.getString(key);
        } else {
            value = Application.get().getResourceSettings().getLocalizer().getString(key, null);
        }

        return value;
    }

    /**
     * Translates the {@code object} into resource key that will be used to lookup the value shown
     * to the user
     * 
     * @param object
     * @return resource key
     */
    protected String resourceKey(T object) {
        return Classes.simpleName(object.getDeclaringClass()) + '.' + object.name();
    }

    /** {@inheritDoc} */
    @Override
    public String getIdValue(T object, int index) {
        return object.name();
    }
}