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/*
* Copyright (C) 2012 The Android Open Source Project
*
* 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 android.util;
/**
* A ValueModel is an abstraction for a 'slot' or place in memory in which a value
* may be stored and retrieved. A common implementation of ValueModel is a regular property of
* an object, whose value may be retrieved by calling the appropriate <em>getter</em>
* method and set by calling the corresponding <em>setter</em> method.
*
* @param <T> the value type
*
* @see PropertyValueModel
*/
public abstract class ValueModel<T> {
/**
* The empty model should be used in place of {@code null} to indicate that a
* model has not been set. The empty model has no value and does nothing when it is set.
*/
public static final ValueModel EMPTY = new ValueModel() {
@Override
public Class getType() {
return Object.class;
}
@Override
public Object get() {
return null;
}
@Override
public void set(Object value) {
}
};
protected ValueModel() {
}
/**
* Returns the type of this property.
*
* @return the property type
*/
public abstract Class<T> getType();
/**
* Returns the value of this property.
*
* @return the property value
*/
public abstract T get();
/**
* Sets the value of this property.
*
* @param value the new value for this property
*/
public abstract void set(T value);
}
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