org.springframework.core.enums.LabeledEnum Maven / Gradle / Ivy
/*
* 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.enums;
import java.io.Serializable;
import java.util.Comparator;
import org.springframework.util.comparator.CompoundComparator;
import org.springframework.util.comparator.NullSafeComparator;
/**
* A interface for objects that represent a labled enumeration.
* Each such enum instance has the following characteristics:
*
*
* - A type that identifies the enum's class.
* For example:
com.mycompany.util.FileFormat
.
*
* - A code that uniquely identifies the enum within the context of its type.
* For example: "CSV". Different classes of codes are possible
* (Character, Integer, String).
*
*
- A descriptive label. For example: "the CSV File Format".
*
*
* @author Keith Donald
* @since 1.2.2
*/
public interface LabeledEnum extends Comparable, Serializable {
/**
* Return this enumeration's type.
*/
Class getType();
/**
* Return this enumeration's code.
* Each code should be unique within enumeration's of the same type.
*/
Comparable getCode();
/**
* Return a descriptive, optional label.
*/
String getLabel();
// Constants for standard enum ordering (Comparator implementations)
/**
* Shared Comparator instance that sorts enumerations by CODE_ORDER
.
*/
Comparator CODE_ORDER = new Comparator() {
public int compare(Object o1, Object o2) {
Comparable c1 = ((LabeledEnum) o1).getCode();
Comparable c2 = ((LabeledEnum) o2).getCode();
return c1.compareTo(c2);
}
};
/**
* Shared Comparator instance that sorts enumerations by LABEL_ORDER
.
*/
Comparator LABEL_ORDER = new Comparator() {
public int compare(Object o1, Object o2) {
LabeledEnum e1 = (LabeledEnum) o1;
LabeledEnum e2 = (LabeledEnum) o2;
Comparator comp = new NullSafeComparator(String.CASE_INSENSITIVE_ORDER, true);
return comp.compare(e1.getLabel(), e2.getLabel());
}
};
/**
* Shared Comparator instance that sorts enumerations by LABEL_ORDER
,
* then CODE_ORDER
.
*/
Comparator DEFAULT_ORDER =
new CompoundComparator(new Comparator[] { LABEL_ORDER, CODE_ORDER });
}