Cat command implementation

Author: geektimus

filesystem/src/main/scala/com/codingmaniacs/scala/exercises/fs/commands/Cat.scala

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2019 Geektimus
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package com.codingmaniacs.scala.exercises.fs.commands
+
+import com.codingmaniacs.scala.exercises.fs.State
+
+class Cat(filename: String) extends Command {
+  override def apply(state: State): State = {
+    val wd = state.workingDir
+    val dirEntry = wd.findEntry(filename)
+    if (dirEntry == null || !dirEntry.isFile) {
+      state.setMessage(s"$filename: No such file")
+    } else {
+      state.setMessage(dirEntry.asFile.contents)
+    }
+  }
+}

filesystem/src/main/scala/com/codingmaniacs/scala/exercises/fs/commands/Command.scala

@@ -36,6 +36,7 @@ object Command {
   val CD = "cd"
   val RM = "rm"
   val ECHO = "echo"
+  val CAT = "cat"
 
   def emptyCommand: Command = new Command {
     override def apply(state: State): State = state
@@ -84,6 +85,12 @@ object Command {
       } else {
         new Echo(tokens.tail)
       }
+    } else if (CAT.equals(tokens(0))) {
+      if (tokens.length < 2) {
+        incompleteCommand(CAT)
+      } else {
+        new Cat(tokens(1))
+      }
     } else {
       new UnknownCommand
     }