Search through XMLs with Java 8 - search

Question

I need to create a tool in java 8 to search through a list of .xml files that are all in the same folder. Each file contains information of this type:
<id>135719887</id>
<FactValue>
<name>FACT.DOCUMENT.TOTAL_DUE_AMOUNT</name>
<valueString>832.15</valueString>
</FactValue>
<FactValue>
<name>FACT.DOCUMENT.AUTO_PAY</name>
<valueString>false</valueString>
</FactValue>
<FactValue>
<name>FACT.DOCUMENT.CREDIT_CARD_EXPIRED</name>
<valueString>false</valueString>
</FactValue>
<FactValue>
<name>FACT.DOCUMENT.HAS_SEDONA_CHARGES</name>
<valueString>true</valueString>
</FactValue>
what required is a tool which can extract from a single or multiple search/query, the FACT code and its value in the following way:
id type value
---------- -------------------- -------
135719887 TOTAL_DUE_AMOUNT 832.15
135719887 AUTO_PAY false
135719887 CREDIT_CARD_EXPIRED false
135719887 HAS_SEDONA_CHARGES true
The queries would be, for instance:
Which Ids have the CREDIT_CARD_EXPIRED = false, AND, AUTO_PAY = true
Which Ids have the CREDIT_CARD_EXPIRED = true, OR, AUTO_PAY = false
What is the value of TOTAL_DUE_AMOUNT fact of the Id xxxxxxxxx
I am interested in a couple of things:
1- What data structure to use
2- How to iterate all the files
Performance is not as importat as flexibility.
Thanks in advance

Answer 1

Let's suppose that FooDto is the POJO class for your XML content, then you can do something like:
public static void main(String[] args) throws Exception {
JAXBContext jaxbContext = JAXBContext.newInstance(FooDto.class);
Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
FooDto fooDto1 = (FooDto) jaxbUnmarshaller.unmarshal(getInput("/Foo1.xml"));
FooDto fooDto2 = (FooDto) jaxbUnmarshaller.unmarshal(getInput("/Foo2.xml"));
List<String> ids = Stream.of(fooDto1, fooDto2)
.filter(Main::creditCardIsNotExpired)
.map(FooDto::getId)
.collect(Collectors.toList());
}
private static boolean creditCardIsNotExpired(FooDto foo) {
return Arrays.stream(foo.getFactValue())
.anyMatch(fact -> fact.getName().equals("FACT.DOCUMENT.CREDIT_CARD_EXPIRED")
&& fact.getValueString().equals("false"));
}
This example gives you all ids for CREDIT_CARD_EXPIRED == false.
Use a DTO, which can be generated from the XML using IDE plugins or other tools.
Read files in a loop and create a collection of DTOs then apply your filters.