Java tutorial
/* * Copyright 2002-2019 the original author or authors. * * 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 * * https://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.springframework.ui; import java.util.Collection; import java.util.Map; import org.springframework.lang.Nullable; /** * Java-5-specific interface that defines a holder for model attributes. * Primarily designed for adding attributes to the model. * Allows for accessing the overall model as a {@code java.util.Map}. * * @author Juergen Hoeller * @since 2.5.1 */ public interface Model { /** * Add the supplied attribute under the supplied name. * @param attributeName the name of the model attribute (never {@code null}) * @param attributeValue the model attribute value (can be {@code null}) */ Model addAttribute(String attributeName, @Nullable Object attributeValue); /** * Add the supplied attribute to this {@code Map} using a * {@link org.springframework.core.Conventions#getVariableName generated name}. * <p><i>Note: Empty {@link java.util.Collection Collections} are not added to * the model when using this method because we cannot correctly determine * the true convention name. View code should check for {@code null} rather * than for empty collections as is already done by JSTL tags.</i> * @param attributeValue the model attribute value (never {@code null}) */ Model addAttribute(Object attributeValue); /** * Copy all attributes in the supplied {@code Collection} into this * {@code Map}, using attribute name generation for each element. * @see #addAttribute(Object) */ Model addAllAttributes(Collection<?> attributeValues); /** * Copy all attributes in the supplied {@code Map} into this {@code Map}. * @see #addAttribute(String, Object) */ Model addAllAttributes(Map<String, ?> attributes); /** * Copy all attributes in the supplied {@code Map} into this {@code Map}, * with existing objects of the same name taking precedence (i.e. not getting * replaced). */ Model mergeAttributes(Map<String, ?> attributes); /** * Does this model contain an attribute of the given name? * @param attributeName the name of the model attribute (never {@code null}) * @return whether this model contains a corresponding attribute */ boolean containsAttribute(String attributeName); /** * Return the attribute value for the given name, if any. * @param attributeName the name of the model attribute (never {@code null}) * @return the corresponding attribute value, or {@code null} if none * @since 5.2 */ @Nullable Object getAttribute(String attributeName); /** * Return the current set of model attributes as a Map. */ Map<String, Object> asMap(); }