Refactor to InputStream instead of URL

InputStream is the common denominator and contains enough information to
construct the ThreadBuffer (and thus the Reader).

Author: Matthew L Daniel

src/main/java/com/maxmind/db/Reader.java

@@ -3,8 +3,8 @@
 import java.io.Closeable;
 import java.io.File;
 import java.io.IOException;
+import java.io.InputStream;
 import java.net.InetAddress;
-import java.net.URL;
 import java.nio.ByteBuffer;
 
 import com.fasterxml.jackson.databind.JsonNode;
@@ -56,12 +56,12 @@ public Reader(File database) throws IOException {
     /**
      * Constructs a Reader as if in mode {@link FileMode#MEMORY}, without using
      * a <code>File</code> instance.
-     * @param source the URL that points to the MaxMind DB file.
+     * @param source the InputStream that contains the MaxMind DB file.
      * @throws IOException
-     *             if there is an error opening or reading from the file.
+     *             if there is an error reading from the Stream.
      */
-    public Reader(URL source) throws IOException {
-        this(ThreadBuffer.newInstance(source), source.getFile());
+    public Reader(InputStream source) throws IOException {
+        this(ThreadBuffer.newInstance(source), "an InputStream");
     }
 
     /**

src/main/java/com/maxmind/db/ThreadBuffer.java

@@ -1,50 +1,37 @@
 package com.maxmind.db;
 
+import java.io.ByteArrayOutputStream;
 import java.io.Closeable;
 import java.io.File;
 import java.io.InputStream;
 import java.io.IOException;
 import java.io.RandomAccessFile;
-import java.net.URL;
-import java.net.URLConnection;
 import java.nio.ByteBuffer;
-import java.nio.channels.Channels;
 import java.nio.channels.FileChannel;
 import java.nio.channels.FileChannel.MapMode;
-import java.nio.channels.ReadableByteChannel;
 
 import com.maxmind.db.Reader.FileMode;
 
 final class ThreadBuffer extends ThreadLocal<ByteBuffer> implements Closeable {
     /**
      * Construct a ThreadBuffer from the provided URL.
-     * @param source the URL that I will read in and use as the source of my
-     *               bytes.
+     * @param stream the source of my bytes.
      * @return a newly constructed instance based on the contents of your URL.
-     * @throws IOException if unable to read from your source, or if your
-     * source does not return all of its contents (short read).
+     * @throws IOException if unable to read from your source.
+     * @throws NullPointerException if you provide a NULL InputStream
      */
-    public static ThreadBuffer newInstance(URL source) throws IOException {
-        final URLConnection conn = source.openConnection();
-        conn.connect();
-
-        final InputStream stream = conn.getInputStream();
-        final int length = conn.getContentLength();
-        final ByteBuffer buffer = ByteBuffer.allocate(length);
-        final ReadableByteChannel channel = Channels.newChannel(stream);
-        int bytesRead = 0;
-        while (true) {
-            final int br = channel.read(buffer);
-            if (-1 == br) {
-                throw new IOException(String.format(
-                        "Short read from %s, wanted %d got %d", source, length, bytesRead));
-            }
-            bytesRead += br;
-            if (length == bytesRead) {
-                break;
-            }
+    public static ThreadBuffer newInstance(InputStream stream) throws IOException {
+        if (null == stream) {
+            throw new NullPointerException("Unable to use a NULL InputStream");
+        }
+        final ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        final byte[] buffer = new byte[16 * 1024];
+        int br;
+        while (-1 != (br = stream.read(buffer))) {
+            baos.write(buffer, 0, br);
         }
-        return new ThreadBuffer(buffer);
+        final ByteBuffer bBuffer = ByteBuffer.wrap(baos.toByteArray());
+        return new ThreadBuffer(bBuffer);
     }
 
     // DO NOT PASS THESE OUTSIDE THIS CLASS. Doing so will remove thread

src/test/java/com/maxmind/db/ReaderTest.java

@@ -8,10 +8,10 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.io.InputStream;
 import java.math.BigInteger;
 import java.net.InetAddress;
 import java.net.URI;
-import java.net.URL;
 import java.net.URISyntaxException;
 import java.net.UnknownHostException;
 import java.util.HashMap;
@@ -63,9 +63,10 @@ public void testNoIpV4SearchTreeFile() throws IOException, URISyntaxException {
     }
     @Test
     public void testNoIpV4SearchTreeURL() throws IOException, URISyntaxException {
-        URL resource = ReaderTest.class.getResource(
-                "/maxmind-db/test-data/MaxMind-DB-no-ipv4-search-tree.mmdb");
-        Reader reader = new Reader(resource);
+        InputStream stream = ReaderTest.class.getResource(
+                "/maxmind-db/test-data/MaxMind-DB-no-ipv4-search-tree.mmdb")
+                .openStream();
+        Reader reader = new Reader(stream);
         testNoIpV4SearchTree(reader);
     }
     private void testNoIpV4SearchTree(Reader reader) throws IOException, URISyntaxException {
@@ -87,10 +88,11 @@ public void testDecodingTypesFile() throws URISyntaxException, IOException {
     }
     @Test
     public void testDecodingTypesURL() throws URISyntaxException, IOException {
-        URL resource = ReaderTest.class.getResource(
-                "/maxmind-db/test-data/MaxMind-DB-test-decoder.mmdb");
+        InputStream stream = ReaderTest.class.getResource(
+                "/maxmind-db/test-data/MaxMind-DB-test-decoder.mmdb")
+                .openStream();
 
-        Reader reader = new Reader(resource);
+        Reader reader = new Reader(stream);
         testDecodingTypes(reader);
     }
     private void testDecodingTypes(Reader reader) throws URISyntaxException, IOException {
@@ -146,10 +148,11 @@ public void testZerosFile() throws URISyntaxException, IOException {
     }
     @Test
     public void testZerosURL() throws URISyntaxException, IOException {
-        URL resource = ReaderTest.class.getResource(
-                "/maxmind-db/test-data/MaxMind-DB-test-decoder.mmdb");
+        InputStream stream = ReaderTest.class.getResource(
+                "/maxmind-db/test-data/MaxMind-DB-test-decoder.mmdb")
+                .openStream();
 
-        Reader reader = new Reader(resource);
+        Reader reader = new Reader(stream);
         testZeros(reader);
     }
     private void testZeros(Reader reader) throws URISyntaxException, IOException {
@@ -191,11 +194,12 @@ public void testBrokenDatabaseFile() throws URISyntaxException, IOException {
     }
     @Test
     public void testBrokenDatabaseURL() throws URISyntaxException, IOException {
-        URL resource = ReaderTest.class
+        InputStream stream = ReaderTest.class
                 .getResource(
-                        "/maxmind-db/test-data/GeoIP2-City-Test-Broken-Double-Format.mmdb");
+                        "/maxmind-db/test-data/GeoIP2-City-Test-Broken-Double-Format.mmdb")
+                .openStream();
 
-        Reader reader = new Reader(resource);
+        Reader reader = new Reader(stream);
         testBrokenDatabase(reader);
     }
     private void testBrokenDatabase(Reader reader) throws URISyntaxException, IOException {
@@ -221,11 +225,12 @@ public void testBrokenSearchTreePointerFile() throws URISyntaxException,
     @Test
     public void testBrokenSearchTreePointerURL() throws URISyntaxException,
             IOException {
-        URL resource = ReaderTest.class
+        InputStream stream = ReaderTest.class
                 .getResource(
-                        "/maxmind-db/test-data/MaxMind-DB-test-broken-pointers-24.mmdb");
+                        "/maxmind-db/test-data/MaxMind-DB-test-broken-pointers-24.mmdb")
+                .openStream();
 
-        Reader reader = new Reader(resource);
+        Reader reader = new Reader(stream);
         testBrokenSearchTreePointer(reader);
     }
     private void testBrokenSearchTreePointer(Reader reader) throws URISyntaxException,
@@ -252,11 +257,12 @@ public void testBrokenDataPointerFile() throws UnknownHostException,
     @Test
     public void testBrokenDataPointerURL() throws UnknownHostException,
             IOException, URISyntaxException {
-        URL resource = ReaderTest.class
+        InputStream stream = ReaderTest.class
                 .getResource(
-                        "/maxmind-db/test-data/MaxMind-DB-test-broken-pointers-24.mmdb");
+                    "/maxmind-db/test-data/MaxMind-DB-test-broken-pointers-24.mmdb")
+                .openStream();
 
-        Reader reader = new Reader(resource);
+        Reader reader = new Reader(stream);
         testBrokenDataPointer(reader);
     }
     private void testBrokenDataPointer(Reader reader) throws UnknownHostException,