org.springframework.ui.ModelMap Maven / Gradle / Ivy
/*
* Copyright 2002-2023 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.LinkedHashMap;
import java.util.Map;
import org.springframework.core.Conventions;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
/**
* Implementation of {@link java.util.Map} for use when building model data for use
* with UI tools. Supports chained calls and generation of model attribute names.
*
* This class serves as generic model holder for Servlet MVC but is not tied to it.
* Check out the {@link Model} interface for an interface variant.
*
* @author Rob Harrop
* @author Juergen Hoeller
* @since 2.0
* @see Conventions#getVariableName
* @see org.springframework.web.servlet.ModelAndView
*/
@SuppressWarnings("serial")
public class ModelMap extends LinkedHashMap {
/**
* Construct a new, empty {@code ModelMap}.
*/
public ModelMap() {
}
/**
* Construct a new {@code ModelMap} containing the supplied attribute
* under the supplied name.
* @see #addAttribute(String, Object)
*/
public ModelMap(String attributeName, @Nullable Object attributeValue) {
addAttribute(attributeName, attributeValue);
}
/**
* Construct a new {@code ModelMap} containing the supplied attribute.
* Uses attribute name generation to generate the key for the supplied model
* object.
* @see #addAttribute(Object)
*/
public ModelMap(Object attributeValue) {
addAttribute(attributeValue);
}
/**
* 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})
*/
public ModelMap addAttribute(String attributeName, @Nullable Object attributeValue) {
Assert.notNull(attributeName, "Model attribute name must not be null");
put(attributeName, attributeValue);
return this;
}
/**
* Add the supplied attribute to this {@code Map} using a
* {@link org.springframework.core.Conventions#getVariableName generated name}.
* Note: Empty {@link 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.
* @param attributeValue the model attribute value (never {@code null})
*/
public ModelMap addAttribute(Object attributeValue) {
Assert.notNull(attributeValue, "Model object must not be null");
if (attributeValue instanceof Collection collection && collection.isEmpty()) {
return this;
}
return addAttribute(Conventions.getVariableName(attributeValue), attributeValue);
}
/**
* Copy all attributes in the supplied {@code Collection} into this
* {@code Map}, using attribute name generation for each element.
* @see #addAttribute(Object)
*/
public ModelMap addAllAttributes(@Nullable Collection attributeValues) {
if (attributeValues != null) {
for (Object attributeValue : attributeValues) {
addAttribute(attributeValue);
}
}
return this;
}
/**
* Copy all attributes in the supplied {@code Map} into this {@code Map}.
* @see #addAttribute(String, Object)
*/
public ModelMap addAllAttributes(@Nullable Map attributes) {
if (attributes != null) {
putAll(attributes);
}
return this;
}
/**
* 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).
*/
public ModelMap mergeAttributes(@Nullable Map attributes) {
if (attributes != null) {
attributes.forEach((key, value) -> {
if (!containsKey(key)) {
put(key, value);
}
});
}
return this;
}
/**
* 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
*/
public boolean containsAttribute(String attributeName) {
return containsKey(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
public Object getAttribute(String attributeName) {
return get(attributeName);
}
}