net.dankito.utils.filesystem.FileSystemWalker.kt Maven / Gradle / Ivy

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Some basic utils needed in many projects
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package net.dankito.utils.filesystem

import org.slf4j.LoggerFactory
import java.io.IOException
import java.nio.file.FileVisitResult
import java.nio.file.FileVisitor
import java.nio.file.Files
import java.nio.file.Path
import java.nio.file.attribute.BasicFileAttributes


open class FileSystemWalker : IFileSystemWalker {

	companion object {
		private val log = LoggerFactory.getLogger(FileSystemWalker::class.java)
	}


	override fun listFiles(startDir: Path): List {
		val discoveredFiles = mutableListOf()

		walk(startDir) { discoveredFile: Path ->
			discoveredFiles.add(discoveredFile)
		}

		return discoveredFiles
	}

	override fun listFilesAndFolders(startDir: Path): FileSystemWalkResult {
		val discoveredFiles = mutableListOf()
		val discoveredFolders = mutableListOf()

		listAllFilesAndFoldersWalk(startDir, { discoveredFolders.add(it) }, { discoveredFiles.add(it) })

		return FileSystemWalkResult(discoveredFiles, discoveredFolders)
	}


	override fun walk(startDir: Path, discoveredFileCallback: (Path) -> Unit) {

		detailedWalk(startDir) { visitedFile: VisitedFile ->
			visitedFile.path?.let { discoveredFile ->
				discoveredFileCallback(discoveredFile)

				FileVisitResult.CONTINUE
			}
		}
	}

	override fun listAllFilesAndFoldersWalk(startDir: Path, preVisitDirectory: ((directory: VisitedFile) -> Unit)?,
											visitedFileCallback: (VisitedFile) -> Unit) {

		detailedWalk(startDir, false, {
			preVisitDirectory?.invoke(it)
			null
		}, null, {
			visitedFileCallback.invoke(it)
			null
		})
	}


	override fun detailedWalk(startDir: Path, abortOnError: Boolean,
							  preVisitDirectory: ((directory: VisitedFile) -> FileVisitResult?)?,
							  postVisitDirectory: ((directory: VisitedFile) -> FileVisitResult?)?,
							  visitedFileCallback: (VisitedFile) -> FileVisitResult?) {

		Files.walkFileTree(startDir, object : FileVisitor {

			// files:

			override fun visitFile(file: Path?, attributes: BasicFileAttributes?): FileVisitResult {
				return visitedFileCallback(VisitedFile(file, attributes)) ?: FileVisitResult.CONTINUE
			}

			override fun visitFileFailed(file: Path?, exception: IOException?): FileVisitResult {
				log.error("Could not visit file '$file'", exception)

				visitedFileCallback(VisitedFile(file, null, exception))

				return if (abortOnError) FileVisitResult.TERMINATE else  FileVisitResult.CONTINUE
			}


			// directories:

			override fun preVisitDirectory(directory: Path?, attributes: BasicFileAttributes?): FileVisitResult {
				return preVisitDirectory?.invoke(VisitedFile(directory, attributes))
						?: FileVisitResult.CONTINUE
			}

			override fun postVisitDirectory(directory: Path?, exception: IOException?): FileVisitResult {
				return postVisitDirectory?.invoke(VisitedFile(directory, null, exception))
						?: FileVisitResult.CONTINUE
			}

		})
	}

}