manjuraj · February 19, 2019 03:49 · Jun 29, 2014 · Jun 29, 2014 · Mar 19, 2014 · Mar 19, 2014
diff --git a/gistfile1.scala b/gistfile1.scala
@@ -1,8 +1,9 @@
 // Purpose:
 // - Ensures that a resource is deterministically disposed of once it goes out of scope
 // - Use this pattern when working with resources that should be closed or managed after use
+//
 // The benefit of this pattern is that it frees the developer from the responsibility of
-// explicitly managing a resources
+// explicitly managing resources
 
 import scala.io.Source
 import java.io._

diff --git a/gistfile1.scala b/gistfile1.scala
@@ -1,5 +1,8 @@
 // Purpose:
-// - Ensure that a resource is deterministically disposed of once it goes out of scope
+// - Ensures that a resource is deterministically disposed of once it goes out of scope
+// - Use this pattern when working with resources that should be closed or managed after use
+// The benefit of this pattern is that it frees the developer from the responsibility of
+// explicitly managing a resources
 
 import scala.io.Source
 import java.io._
@@ -44,4 +47,11 @@ def withPrintWriter[A](name: String, append: Boolean = true)(func: PrintWriter =
 
 withPrintWriter("greetings.txt") { writer =>
   writer.println("hello world!")
-}
+}
+
+
+// Flattening a Loan Pattern
+//
+// When loaning several objects, one often ends up with nested functions which can
+// be flattened using the pattern here: 
+// http://www.casualmiracles.com/2012/04/18/flattening-the-loan-pattern/
diff --git a/gistfile1.scala b/gistfile1.scala
@@ -2,8 +2,8 @@
 // - Ensure that a resource is deterministically disposed of once it goes out of scope
 
 import scala.io.Source
-import java.io.{FileWriter, PrintWriter, BufferedWriter}
-
+import java.io._
+ 
 def withFileIterator[A](name: String, encoding: String = "UTF-8")(func: Iterator[String] => A): A = {
   val source = Source.fromFile(name, "UTF-8")
   val lines = source.getLines()
@@ -18,6 +18,21 @@ withFileIterator("greetings.txt") { lines =>
   lines.length
 }
 
+def withFileLine[A](name: String, encoding: String = "UTF-8")(func: String => A): Unit = {
+  val in = new BufferedReader(new InputStreamReader(new FileInputStream(name), encoding))
+  try {
+    var line = in.readLine
+    while (line != null) {
+      func(line)
+      line = in.readLine
+    }
+  } finally {
+    in.close
+  }
+}
+
+withFileLine("greetings.txt")(println)
+
 def withPrintWriter[A](name: String, append: Boolean = true)(func: PrintWriter => A): A = {
   val writer = new PrintWriter(new BufferedWriter(new FileWriter(name, append)))
   try {

diff --git a/gistfile1.scala b/gistfile1.scala
@@ -4,7 +4,7 @@
 import scala.io.Source
 import java.io.{FileWriter, PrintWriter, BufferedWriter}
 
-def withFileIterator[A](name: String, encoding: String = "UTF-8")(func: Iterator[String] => A) = {
+def withFileIterator[A](name: String, encoding: String = "UTF-8")(func: Iterator[String] => A): A = {
   val source = Source.fromFile(name, "UTF-8")
   val lines = source.getLines()
   try {
@@ -18,7 +18,7 @@ withFileIterator("greetings.txt") { lines =>
   lines.length
 }
 
-def withPrintWriter[A](name: String, append: Boolean = true)(func: PrintWriter => A) = {
+def withPrintWriter[A](name: String, append: Boolean = true)(func: PrintWriter => A): A = {
   val writer = new PrintWriter(new BufferedWriter(new FileWriter(name, append)))
   try {
     func(writer)

diff --git a/gistfile1.scala b/gistfile1.scala
@@ -0,0 +1,32 @@
+// Purpose:
+// - Ensure that a resource is deterministically disposed of once it goes out of scope
+
+import scala.io.Source
+import java.io.{FileWriter, PrintWriter, BufferedWriter}
+
+def withFileIterator[A](name: String, encoding: String = "UTF-8")(func: Iterator[String] => A) = {
+  val source = Source.fromFile(name, "UTF-8")
+  val lines = source.getLines()
+  try {
+    func(lines)
+  } finally {
+    source.close()
+  }
+}
+
+withFileIterator("greetings.txt") { lines => 
+  lines.length
+}
+
+def withPrintWriter[A](name: String, append: Boolean = true)(func: PrintWriter => A) = {
+  val writer = new PrintWriter(new BufferedWriter(new FileWriter(name, append)))
+  try {
+    func(writer)
+  } finally {
+    writer.close()
+  }
+}
+
+withPrintWriter("greetings.txt") { writer =>
+  writer.println("hello world!")
+}