/*
* Copyright 2002-2006 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
*
* 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 org.springframework.core;
/**
* Interface defining a generic contract for attaching and accessing metadata
* to/from arbitrary objects.
*
* @author Rob Harrop
* @since 2.0
*/
public interface AttributeAccessor {
/**
* Set the attribute defined by <code>name</code> to the supplied <code>value</code>.
* If <code>value</code> is <code>null</code>, the attribute is {@link #removeAttribute removed}.
* <p>In general, users should take care to prevent overlaps with other
* metadata attributes by using fully-qualified names, perhaps using
* class or package names as prefix.
* @param name the unique attribute key
* @param value the attribute value to be attached
*/
void setAttribute(String name, Object value);
/**
* Get the value of the attribute identified by <code>name</code>.
* Return <code>null</code> if the attribute doesn't exist.
* @param name the unique attribute key
* @return the current value of the attribute, if any
*/
Object getAttribute(String name);
/**
* Remove the attribute identified by <code>name</code> and return its value.
* Return <code>null</code> if no attribute under <code>name</code> is found.
* @param name the unique attribute key
* @return the last value of the attribute, if any
*/
Object removeAttribute(String name);
/**
* Return <code>true</code> if the attribute identified by <code>name</code> exists.
* Otherwise return <code>false</code>.
* @param name the unique attribute key
*/
boolean hasAttribute(String name);
/**
* Return the names of all attributes.
*/
String[] attributeNames();
}
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