Modify NitfReading classes to support closing / try with resources

Author: svargasConnexta

core-api/src/main/java/org/codice/imaging/nitf/core/common/NitfReader.java

@@ -164,4 +164,12 @@ This is used to ignore some of the file content (e.g. data segments, when only p
         @throws NitfFormatException if something went wrong during parsing (e.g. end of file).
     */
     void skip(final long count) throws NitfFormatException;
+
+    /**
+       Closes the file.
+
+       @throws Exception if there is an error closing the file.
+     */
+
+    void close() throws Exception;
 }

core/src/main/java/org/codice/imaging/nitf/core/common/impl/FileReader.java

@@ -31,7 +31,7 @@
 /**
     NitfReader implementation using a (random access) File.
 */
-public class FileReader extends SharedReader implements NitfReader {
+public class FileReader extends SharedReader implements NitfReader, AutoCloseable {
     // Error Messages
     static final String GENERIC_READ_ERROR_MESSAGE = "Error reading from NITF file: ";
     static final String FILE_NOT_FOUND_EXCEPTION_MESSAGE = "File Not Found Exception opening file:";

core/src/main/java/org/codice/imaging/nitf/core/common/impl/NitfInputStreamReader.java

@@ -25,7 +25,7 @@
 /**
     NitfReader implementation using an InputStream.
 */
-public class NitfInputStreamReader extends SharedReader implements NitfReader {
+public class NitfInputStreamReader extends SharedReader implements NitfReader, AutoCloseable {
 
     private static final Logger LOG = LoggerFactory.getLogger(NitfInputStreamReader.class);
 
@@ -125,4 +125,11 @@ public final void skip(final long count) throws NitfFormatException {
             throw new NitfFormatException(GENERIC_READ_ERROR_MESSAGE + ex.getMessage(), numBytesRead);
         }
     }
+
+    @Override
+    public final void close() throws Exception {
+        if (input != null) {
+            input.close();
+        }
+    }
 }

core/src/main/java/org/codice/imaging/nitf/core/common/impl/SharedReader.java

@@ -21,7 +21,7 @@
 /**
     Shared NitfReader implementation.
 */
-abstract class SharedReader extends NitfReaderDefaultImpl implements NitfReader {
+abstract class SharedReader extends NitfReaderDefaultImpl implements NitfReader, AutoCloseable {
 
     @Override
     public final Integer readBytesAsInteger(final int count) throws NitfFormatException {

core/src/main/java/org/codice/imaging/nitf/core/impl/NitfReaderDefaultImpl.java

@@ -27,7 +27,7 @@
     combination of shared methods and default implementation methods that a concrete
     implementation class can call.
 */
-public abstract class NitfReaderDefaultImpl implements NitfReader {
+public abstract class NitfReaderDefaultImpl implements NitfReader, AutoCloseable {
 
     /**
         The type (version) of NITF file.

core/src/test/java/org/codice/imaging/nitf/core/common/impl/NitfInputStreamReaderTest.java

@@ -53,4 +53,33 @@ public void testEndOfFileException() throws IOException, NitfFormatException {
         NitfReader reader = new NitfInputStreamReader(mockInputStream);
         reader.readBytes(100);
     }
+
+    @Test(expected = NitfFormatException.class)
+    public void testIOExceptionReadingFromClosedStream() throws Exception {
+        InputStream mockInputStream = new InputStream() {
+            boolean closed = false;
+            @Override public int read() throws IOException {
+                throwIOExceptionIfClosed();
+                return 100;
+            }
+            @Override public int read(byte[] buff, int offset, int len) throws IOException {
+                throwIOExceptionIfClosed();
+                return 100;
+            }
+            public void close() throws IOException {
+                throwIOExceptionIfClosed();
+                closed = true;
+            }
+            private void throwIOExceptionIfClosed() throws IOException {
+                if (closed) {
+                    throw new IOException("Stream already closed");
+                }
+            }
+        };
+
+        // IOException is rethrown as NitfFormatException
+        NitfReader reader = new NitfInputStreamReader(mockInputStream);
+        reader.close();
+        reader.readBytes(100);
+    }
 }

fluent/src/main/java/org/codice/imaging/nitf/fluent/impl/NitfParserParsingFlowImpl.java

@@ -39,7 +39,7 @@
 /**
  * A builder class that handles parsing.
  */
-public class NitfParserParsingFlowImpl implements NitfParserParsingFlow {
+public class NitfParserParsingFlowImpl implements NitfParserParsingFlow, AutoCloseable {
     private final NitfReader reader;
 
     private HeapStrategy<ImageInputStream> imageDataStrategy =
@@ -128,4 +128,9 @@ public final NitfSegmentsFlow build(final ParseStrategy parseStrategy)
         NitfParser.parse(reader, parseStrategy);
         return new NitfSegmentsFlowImpl(parseStrategy.getDataSource(), imageDataStrategy::cleanUp);
     }
+
+    @Override
+    public final void close() throws Exception {
+        this.reader.close();
+    }
 }