⌛⌛ Text search inside a 7z file¶

Place the pom.xml file in the round7/sevenzipsearch directory of your local repository and create to this directory the src/main/java subdirectory. You may name freely your classes freely, but they must belong to the fi.tuni.prog3.sevenzipsearch package. Therefore, your files must be in the round7/sevenzipsearch/src/main/java/fi/tuni/prog3/sevenzipsearch directory and the files must have the package fi.tuni.prog3.sevenzipsearch; statement at the very beginning of the class.

NetBeans creates the pom.xml file and the directory structure for this task automatically, provided that you enter correct values, while creating a Maven project. Please, see below the values for the groupId-, artifactId- ja ``version``elements.

There are test material available in the round7/sevenzipsearch directory of the remote material repository.

In this task, you will try handling files compressed with 7z compression by using the Apache Commons Compress library. You will actually need the following two libraries as dependencies:

• Apache Commons Compress

  • Info page from Maven Central: https://search.maven.org/artifact/org.apache.commons/commons-compress/1.21/jar

  • Documentation: https://commons.apache.org/proper/commons-compress/examples.html

• XZ

  • Info page from Maven Central: https://search.maven.org/artifact/org.tukaani/xz/1.9/jar

  • Note! This dependency is needed only indirectly: Apache Commons Compress library uses it internally. Your code does not need to refer to this library anywhere. It is enough that you add the dependency definition into the pom.xml file.

7z files (Wikipedia article) are similar to zip files but they use a more efficient compression algorithm.

Your task is to implement a program that searches for occurrences of a given search word in the text files contained in a given 7z file. To be more precise, the program must work as follows:

• The prints the prompt File:, after which the file name is read from the user. Next the prompt Query: is printed and the word to be searched is read. Afterwards one empty line is printed.

• The program scans the files in the given 7z file and performs a word search in each found text file.

  • A file is recognized as a text file based on its ending: the search is performed if and only if the file ending is .txt”.

  • At the beginning of each search the name of the file is printed out.

  • At the end of each search one extra new line is printed.

• Performing the word search:

  • The file is read one line at a time and all occurrences of the search word are searched from each line, ignoring character case.

  • If at least one occurrence is found, the line in question is printed out in the form “line number: line”, where line number is the number of the line in question (the first line in the file has number 1), and line is the line in question formatted in such a way that all occurrences of the search word have been changed to use upper case letters.

The example outputs clarify the format.

The automatic tests, and the ones given below, assume that you make the following definitions in your pom.xml project file:

• The value of groupId is fi.tuni.prog3.

• The value of artifactId is sevenzipsearch.

• The value of version is 1.0.

• The values of the maven.compiler.source and maven.compiler.target elements are 17 or lower. The grader uses Java 17, so any newer versions won’t work.

• A Onejar plugin definition where the value of mainClass element refers to the main class of your program, which you can name freely in this task. For example, if your main class is named SevenZipSearch, the element value is fi.tuni.prog3.sevenzipsearch.SevenZipSearch.

Hint: Heikki Hyyrö’s coding demonstration video in Chapter 7.2.

NB: Do NOT create several Scanner instances reading the standard input (System.in). Only create one and use the same one for the whole program. Only the first Scanner attached to System.in will receive input. The same holds true if you use another class like InputStreamReader to read the user input.