3: Add FileProvider

src/main/java/com/bartek/esa/di/DependencyInjector.java

@@ -3,11 +3,13 @@ package com.bartek.esa.di;
 import com.bartek.esa.EsaMain;
 import com.bartek.esa.cli.di.CliModule;
 import com.bartek.esa.dispatcher.di.DispatcherModule;
+import com.bartek.esa.file.di.FileModule;
 import dagger.Component;
 
 @Component(modules = {
         CliModule.class,
-        DispatcherModule.class
+        DispatcherModule.class,
+        FileModule.class
 })
 public interface DependencyInjector {
     EsaMain esa();

src/main/java/com/bartek/esa/file/di/FileModule.java

@@ -0,0 +1,14 @@
+package com.bartek.esa.file.di;
+
+import com.bartek.esa.file.provider.FileProvider;
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class FileModule {
+
+    @Provides
+    public FileProvider fileProvider() {
+        return new FileProvider();
+    }
+}

src/main/java/com/bartek/esa/file/provider/FileProvider.java

@@ -0,0 +1,75 @@
+package com.bartek.esa.file.provider;
+
+import com.bartek.esa.error.EsaException;
+import io.vavr.control.Try;
+
+import javax.inject.Inject;
+import java.io.File;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+public class FileProvider {
+
+    @Inject
+    public FileProvider() {
+
+    }
+
+    public String readFile(File file) {
+        StringBuilder content = new StringBuilder();
+        Try.run(() -> Files.lines(file.toPath())
+                .map(line -> line + "\n")
+                .forEach(content::append));
+
+        return content.toString();
+    }
+
+    public Set<File> findFilesRecursively(String path, String globPattern) {
+        return findFilesRecursivelyInSubpath(path, "", globPattern);
+    }
+
+    public Set<File> findFilesRecursivelyInSubpath(String path, String subpath, String globPattern) {
+        return Try.of(() -> Files.walk(Paths.get(path))
+                .filter(p -> p.toString().contains(subpath))
+                .filter(p -> matchesGlobPattern(p.getFileName().toString(), globPattern))
+                .map(Path::toFile)
+                .collect(Collectors.toSet()))
+                .getOrElseThrow(EsaException::new);
+    }
+
+    public boolean matchesGlobPattern(String filename, String globPattern) {
+        return filename.matches(createRegexFromGlob(globPattern));
+    }
+
+    private String createRegexFromGlob(String glob) {
+        StringBuilder out = new StringBuilder("^");
+
+        glob
+                .chars()
+                .mapToObj(i -> (char) i)
+                .map(this::globCharacterToRegexString)
+                .forEach(out::append);
+
+        out.append('$');
+
+        return out.toString();
+    }
+
+    private String globCharacterToRegexString(char character) {
+        switch (character) {
+            case '*':
+                return ".*";
+            case '?':
+                return ".";
+            case '.':
+                return "\\.";
+            case '\\':
+                return "\\\\";
+            default:
+                return String.valueOf(character);
+        }
+    }
+}