/*
 * 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 java.util.Map. 
Author:
Juergen Hoeller
Since:
2.5.1/**
 * 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.
Params:
attributeName – the name of the model attribute (never null)
attributeValue – the model attribute value (can be null)/**
	 * 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 Map using a generated name. 
Note: Empty 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 null rather than for empty collections as is already done by JSTL tags.
Params:
attributeValue – the model attribute value (never null)/**
	 * 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 Collection into this Map, using attribute name generation for each element. 
See Also:
addAttribute(Object)/**
	 * 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 Map into this Map. 
See Also:
addAttribute(String, Object)/**
	 * 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 Map into this Map, with existing objects of the same name taking precedence (i.e. not getting replaced). /**
	 * 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?
Params:
attributeName – the name of the model attribute (never null)
Returns:
whether this model contains a corresponding attribute/**
	 * 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.
Params:
attributeName – the name of the model attribute (never null)
Returns:
the corresponding attribute value, or null if none
Since:
5.2/**
	 * 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.
/**
	 * Return the current set of model attributes as a Map.
	 */
	Map<String, Object> asMap();

}