TemplateNumberModel.java

/*
 * Copyright 2014 Attila Szegedi, Daniel Dekany, Jonathan Revusky
 * 
 * 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 freemarker.template;

import freemarker.core.ArithmeticEngine;

/**
 * "number" template language data type; an object that stores a number. There's only one numerical type as far as the
 * template language is concerned, but it can store its value using whatever Java number type. Making operations between
 * numbers (and so the coercion rules) is up to the {@link ArithmeticEngine}.
 * 
 * <p>
 * Objects of this type should be immutable, that is, calling {@link #getAsNumber()} should always return the same value
 * as for the first time.
 */
public interface TemplateNumberModel extends TemplateModel {

    /**
     * Returns the numeric value. The return value must not be {@code null}.
     *
     * @return the {@link Number} instance associated with this number model.
     */
    public Number getAsNumber() throws TemplateModelException;
    
}