#42 - Fixed stream issues.

vzurauskas · Jul 29, 2020 · 41ac18b · 41ac18b
1 parent f8b5863
commit 41ac18b
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Showing 7 changed files with 100 additions and 8 deletions.
diff --git a/src/main/java/com/vzurauskas/nereides/javax/AutoResetInputStream.java b/src/main/java/com/vzurauskas/nereides/javax/AutoResetInputStream.java
@@ -0,0 +1,26 @@
+package com.vzurauskas.nereides.javax;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+public final class AutoResetInputStream extends InputStream {
+
+    private final InputStream origin;
+
+    public AutoResetInputStream(InputStream origin) {
+        super();
+        origin.mark(1 << 24);
+        this.origin = origin;
+    }
+
+    @Override
+    public void close() throws IOException {
+        super.close();
+        origin.reset();
+    }
+
+    @Override
+    public int read() throws IOException {
+        return origin.read();
+    }
+}
diff --git a/src/main/java/com/vzurauskas/nereides/javax/ByteArray.java b/src/main/java/com/vzurauskas/nereides/javax/ByteArray.java
@@ -20,6 +20,7 @@ final class ByteArray {
             while (true) {
                 int size = stream.read(data, 0, data.length);
                 if (size == -1) {
+                    stream.close();
                     break;
                 }
                 output.write(data, 0, size);

diff --git a/src/main/java/com/vzurauskas/nereides/javax/Cached.java b/src/main/java/com/vzurauskas/nereides/javax/Cached.java
@@ -0,0 +1,19 @@
+package com.vzurauskas.nereides.javax;
+
+import java.util.function.Supplier;
+
+final class Cached<T> {
+    private final Supplier<T> scalar;
+    private T value;
+
+    Cached(Supplier<T> scalar) {
+        this.scalar = scalar;
+    }
+
+    public T value() {
+        if (value == null) {
+            value = scalar.get();
+        }
+        return value;
+    }
+}
diff --git a/src/main/java/com/vzurauskas/nereides/javax/Json.java b/src/main/java/com/vzurauskas/nereides/javax/Json.java
@@ -92,7 +92,11 @@ public Of(String string) {
          * @param bytes JSON represented by an array of bytes.
          */
         public Of(byte[] bytes) {
-            this(new ByteArrayInputStream(bytes));
+            this(
+                new AutoResetInputStream(
+                    new ByteArrayInputStream(bytes)
+                )
+            );
         }
 
         /**
@@ -110,12 +114,20 @@ public Of(InputStream stream) {
          */
         public Of(Path path) {
             this(
-                () -> new Unchecked<>(
-                    () -> new ByteArrayInputStream(Files.readAllBytes(path))
-                ).value()
+                new Cached<>(
+                    () -> new Unchecked<>(
+                        () -> new AutoResetInputStream(
+                            new ByteArrayInputStream(Files.readAllBytes(path))
+                        )
+                    ).value()
+                )
             );
         }
 
+        private Of(Cached<InputStream> cached) {
+            this(cached::value);
+        }
+
         private Of(Json json) {
             this.origin = json;
         }

diff --git a/src/main/java/com/vzurauskas/nereides/javax/SmartJson.java b/src/main/java/com/vzurauskas/nereides/javax/SmartJson.java
@@ -32,7 +32,7 @@
 public final class SmartJson implements Json {
 
     private final Json origin;
-    private final Unchecked<JsonStructure> structure;
+    private final Cached<JsonStructure> structure;
 
     /**
      * Constructor.
@@ -41,13 +41,15 @@ public final class SmartJson implements Json {
     public SmartJson(Json origin) {
         this(
             origin,
-            new Unchecked<>(
-                () -> javax.json.Json.createReader(origin.bytes()).read()
+            new Cached<>(
+                () -> new Unchecked<>(
+                    () -> javax.json.Json.createReader(origin.bytes()).read()
+                ).value()
             )
         );
     }
 
-    private SmartJson(Json origin, Unchecked<JsonStructure> structure) {
+    private SmartJson(Json origin, Cached<JsonStructure> structure) {
         this.origin = origin;
         this.structure = structure;
     }

diff --git a/src/test/java/com/vzurauskas/nereides/javax/JsonOfTest.java b/src/test/java/com/vzurauskas/nereides/javax/JsonOfTest.java
@@ -4,7 +4,9 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
+import java.io.File;
 import java.io.IOException;
+import java.io.PrintStream;
 import java.net.URISyntaxException;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -95,4 +97,25 @@ void toStringWorksEvenIfMalformed() {
             new Json.Of("malformed").toString()
         );
     }
+
+    @Test
+    void canReadTwice() {
+        String string = "{\"number\": 12}";
+        Json json = new Json.Of(string);
+        assertArrayEquals(string.getBytes(), new ByteArray(json).value());
+        assertArrayEquals(string.getBytes(), new ByteArray(json).value());
+    }
+
+    @Test
+    void doesntReadFileEachTimeJsonIsAccessed() throws IOException {
+        String string = "{\"number\": 12}";
+        File file = File.createTempFile("whatever", "whatever");
+        try (PrintStream ps = new PrintStream(file)) {
+            ps.print(string);
+        }
+        Json json = new Json.Of(file.toPath());
+        assertArrayEquals(string.getBytes(), new ByteArray(json).value());
+        file.delete();
+        assertArrayEquals(string.getBytes(), new ByteArray(json).value());
+    }
 }
diff --git a/src/test/java/com/vzurauskas/nereides/javax/SmartJsonTest.java b/src/test/java/com/vzurauskas/nereides/javax/SmartJsonTest.java
@@ -173,4 +173,13 @@ void toStringWorksOfMalformed() {
             new SmartJson(new Json.Of("malformed")).toString()
         );
     }
+
+    @Test
+    void canReadTwice() {
+        SmartJson json = new SmartJson(
+            new Json.Of("{\"field1\":\"value1\",\"field2\":\"value2\"}")
+        );
+        assertEquals("value1", json.leaf("field1"));
+        assertEquals("value1", json.leaf("field1"));
+    }
 }