io.guise.framework.model.ValueConverterInfoModel Maven / Gradle / Ivy

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Guise™ Internet application framework.

There is a newer version: 0.5.3

/*
 * Copyright © 2005-2008 GlobalMentor, Inc. 
 *
 * Licensed 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 io.guise.framework.model;

import static java.util.Objects.*;

import io.guise.framework.converter.ConversionException;
import io.guise.framework.converter.Converter;

/**
 * An info model that converts a value to a string for the label. If no label is explicitly set, the label will represent the given value converted to a string
 * using the given converter.
 * @param  The type of value represented by the label.
 * @author Garret Wilson
 */
public class ValueConverterInfoModel extends DefaultInfoModel {

	/** The represented value. */
	private final V value;

	/** @return The represented value. */
	public final V getValue() {
		return value;
	}

	/** The converter to use for displaying the value as a string. */
	private final Converter converter;

	/** @return The converter to use for displaying the value as a string. */
	public Converter getConverter() {
		return converter;
	}

	/**
	 * Value and converter constructor.
	 * @param value The value to represent as a label.
	 * @param converter The converter to use for displaying the value as a string.
	 * @throws NullPointerException if the given converter is null.
	 */
	public ValueConverterInfoModel(final V value, final Converter converter) {
		this.value = value; //save the value
		this.converter = requireNonNull(converter, "Converter cannot be null."); //save the converter		
	}

	@Override
	public String getLabel() {
		String label = super.getLabel(); //get the specified label
		if(label == null) { //if no label is specified
			try {
				label = getConverter().convertValue(getValue()); //convert the value to a string
			} catch(final ConversionException conversionException) {
				throw new AssertionError(conversionException); //TODO fix better
			}
		}
		return label; //return the label
	}

}