区间合并工具Section

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Section

section是一个区间merge工具类，工具类采用泛型+Comparator+递归来实现通用性处理，并预留data merge SPI提供具体的数据merge策略。

Usage

Create section

使用Section提供的工厂方法build来创建对象

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Section<T> build(int startDate, int endDate, T data, Comparator comparator, DataProcessor<T> dataProcessor)

Merge method

merge one to one

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List<Section<T>> merge(Section<T> source, Section<T> target)

merge one to List

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List<Section<T>> merge(Section<T> source, List<Section<T>> target, boolean mergeSelf)

merge List to one

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List<Section<T>> merge(List<Section<T>> source, Section<T> target, boolean mergeSelf)

merge List to List

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List<Section<T>> merge(List<Section<T>> source, List<Section<T>> target)

Comparator

merge对象比较使用，用于判断两个数据是否可以合并，例如：

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public static class SectionComparator implements Comparator<SectionModel> {
        @Override
        public int compare(SectionModel o1, SectionModel o2) {
            return ComparisonChain.start()
                    .compare(o1.day, o2.day)
                    .compare(o1.desc, o2.desc)
                    .result();
        }
    }
```    


### Merge SPI
#### SPI

interface DataProcessor {
T dataMerge(T source, T target);
}

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#### Default Handler

public static class DefaultDataProcessor implements DataProcessor {

    @Override
    public T dataMerge(T source, T target) {
        return target;
    }
}

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## Simple Example
### unit test

@Test
public void buildTest() {

    SectionModel sectionModel = new SectionModel();

    sectionModel.setStartDate(20150101);
    sectionModel.setEndDate(20160101);
    sectionModel.setDay(10);
    sectionModel.setDesc("123");
    Section<SectionModel> section = Section.build(sectionModel);

    SectionModel sectionModel2 = new SectionModel();

    sectionModel2.setStartDate(20151001);
    sectionModel2.setEndDate(20160601);
    sectionModel2.setDay(10);
    sectionModel2.setDesc("1234");
    Section<SectionModel> section2 = Section.build(sectionModel2);

    List<Section<SectionModel>> sectionList =  Section.merge(section,section2);

    System.out.println(sectionList);

}

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### merge result

[Section{startDate=20150101, endDate=20150930, data=SectionModel{startDate=20150101, endDate=20160101, day=10, desc=123}}, Section{startDate=20151001, endDate=20160601, data=SectionModel{startDate=20151001, endDate=20160601, day=10, desc=1234}}]

```