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Guava: Range 开闭区间

Guava: Range 开闭区间

作者: kexue | 来源:发表于2016-06-06 18:12 被阅读376次
    package com.wdxxl.guava.model.range;
    
    import java.util.Set;
    
    import com.google.common.collect.ContiguousSet;
    import com.google.common.collect.DiscreteDomain;
    import com.google.common.collect.Range;
    /**
     * http://docs.guava-libraries.googlecode.com/git-history/v12.0/javadoc/com/google/common/collect/Range.html
     * 
     * Notation Definition  Factory method
     * (a..b)  {x | a < x < b}     open
     * [a..b]  {x | a <= x <= b}   closed
     * (a..b]  {x | a < x <= b}    openClosed
     * [a..b)  {x | a <= x < b}    closedOpen
     * (a..+∞) {x | x > a}         greaterThan
     * [a..+∞) {x | x >= a}        atLeast
     * (-∞..b) {x | x < b}         lessThan
     * (-∞..b] {x | x <= b}        atMost
     * (-∞..+∞)    {x}             all
     */
    public class RangeTest {
    
        public static void main(String[] args) {
            Range<Integer> range = Range.closed(20, 30);
            print("closed", ContiguousSet.create(range, DiscreteDomain.integers()));
    
            range = Range.open(20, 30);
            print("open", ContiguousSet.create(range, DiscreteDomain.integers()));
    
            range = Range.openClosed(20, 30);
            print("openClosed", ContiguousSet.create(range, DiscreteDomain.integers()));
    
            range = Range.closedOpen(20, 30);
            print("closedOpen", ContiguousSet.create(range, DiscreteDomain.integers()));
    
            range = Range.greaterThan(20);
            System.out.println("greaterThan: "
                    + ContiguousSet.create(range, DiscreteDomain.integers()).toString());
    
            range = Range.atLeast(20);
            System.out.println(
                    "atLeast: " + ContiguousSet.create(range, DiscreteDomain.integers()).toString());
    
            range = Range.lessThan(30);
            System.out.println(
                    "lessThan: " + ContiguousSet.create(range, DiscreteDomain.integers()).toString());
    
            range = Range.atMost(30);
            System.out.println(
                    "atMost: " + ContiguousSet.create(range, DiscreteDomain.integers()).toString());
    
            range = Range.all();
            System.out.println(
                    "all: " + ContiguousSet.create(range, DiscreteDomain.integers()).toString());
        }
    
        public static void print(String type, Set<Integer> ranges) {
            boolean isFirst = true;
            System.out.print(type + ": ");
            for (Integer i : ranges) {
                System.out.print(isFirst ? i : "," + i);
                isFirst = false;
            }
            System.out.println();
        }
        /**
         * closed: 20,21,22,23,24,25,26,27,28,29,30
         * open: 21,22,23,24,25,26,27,28,29
         * openClosed: 21,22,23,24,25,26,27,28,29,30
         * closedOpen: 20,21,22,23,24,25,26,27,28,29
         * greaterThan: [21‥2147483647]
         * atLeast: [20‥2147483647]
         * lessThan: [-2147483648‥29]
         * atMost: [-2147483648‥30]
         * all: [-2147483648‥2147483647]
         */
    }
    

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