Added the MemFileChannel to enable working with dbs completely in memory

git-svn-id: https://svn.code.sf.net/p/jackcess/code/jackcess/trunk@642 f203690c-595d-4dc9-a70b-905162fa7fd2

3 files changed, 191 insertions, 7 deletions

diff --git a/test/src/java/com/healthmarketscience/jackcess/DatabaseTest.java b/test/src/java/com/healthmarketscience/jackcess/DatabaseTest.java
index 51c7efd..1c0c2eb 100644
--- a/test/src/java/com/healthmarketscience/jackcess/DatabaseTest.java
+++ b/test/src/java/com/healthmarketscience/jackcess/DatabaseTest.java
@@ -37,6 +37,7 @@ import java.io.OutputStream;
 import java.io.PrintWriter;
 import java.math.BigDecimal;
 import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
 import java.sql.Types;
 import java.text.DateFormat;
 import java.text.SimpleDateFormat;
@@ -78,8 +79,17 @@ public class DatabaseTest extends TestCase {
   public static Database open(FileFormat fileFormat, File file) 
     throws Exception 
   {
+    return open(fileFormat, file, false);
+  }
+
+  private static Database open(FileFormat fileFormat, File file, 
+                               boolean inMem) 
+    throws Exception 
+  {
+    FileChannel channel = (inMem ? MemFileChannel.newChannel(file, "r") 
+                           : null);
     final Database db = new DatabaseBuilder(file).setReadOnly(true)
-      .setAutoSync(_autoSync).open();
+      .setAutoSync(_autoSync).setChannel(channel).open();
     assertEquals("Wrong JetFormat.", fileFormat.getJetFormat(), 
                  db.getFormat());
     assertEquals("Wrong FileFormat.", fileFormat, db.getFileFormat());
@@ -90,6 +100,10 @@ public class DatabaseTest extends TestCase {
     return open(testDB.getExpectedFileFormat(), testDB.getFile());
   }
 
+  public static Database openMem(TestDB testDB) throws Exception {
+    return open(testDB.getExpectedFileFormat(), testDB.getFile(), true);
+  }
+
   public static Database create(FileFormat fileFormat) throws Exception {
     return create(fileFormat, false);
   }
@@ -97,8 +111,20 @@ public class DatabaseTest extends TestCase {
   public static Database create(FileFormat fileFormat, boolean keep) 
     throws Exception 
   {
+    return create(fileFormat, keep, false);
+  }
+
+  public static Database createMem(FileFormat fileFormat) throws Exception {
+    return create(fileFormat, false, true);
+  }
+
+  private static Database create(FileFormat fileFormat, boolean keep, 
+                                 boolean inMem) 
+    throws Exception 
+  {
+    FileChannel channel = (inMem ? MemFileChannel.newChannel() : null);
     return new DatabaseBuilder(createTempFile(keep)).setFileFormat(fileFormat)
-      .setAutoSync(_autoSync).create();
+      .setAutoSync(_autoSync).setChannel(channel).create();
   }
 
 
@@ -301,6 +327,20 @@ public class DatabaseTest extends TestCase {
   public void testWriteAndRead() throws Exception {
     for (final FileFormat fileFormat : SUPPORTED_FILEFORMATS) {
       Database db = create(fileFormat);
+      doTestWriteAndRead(db);
+      db.close();
+    }
+  }
+  
+  public void testWriteAndReadInMem() throws Exception {
+    for (final FileFormat fileFormat : SUPPORTED_FILEFORMATS) {
+      Database db = createMem(fileFormat);
+      doTestWriteAndRead(db);
+      db.close();
+    }
+  }
+  
+  private static void doTestWriteAndRead(Database db) throws Exception {
       createTestTable(db);
       Object[] row = createTestRow();
       row[3] = null;
@@ -320,11 +360,8 @@ public class DatabaseTest extends TestCase {
         assertEquals(row[6], readRow.get("G"));
         assertEquals(row[7], readRow.get("H"));
       }
-
-      db.close();
-    }
   }
-  
+
   public void testWriteAndReadInBatch() throws Exception {
     for (final FileFormat fileFormat : SUPPORTED_FILEFORMATS) {
       Database db = create(fileFormat);
diff --git a/test/src/java/com/healthmarketscience/jackcess/IndexCodesTest.java b/test/src/java/com/healthmarketscience/jackcess/IndexCodesTest.java
index a479038..ed71ebe 100644
--- a/test/src/java/com/healthmarketscience/jackcess/IndexCodesTest.java
+++ b/test/src/java/com/healthmarketscience/jackcess/IndexCodesTest.java
@@ -68,7 +68,7 @@ public class IndexCodesTest extends TestCase {
   public void testIndexCodes() throws Exception
   {
     for (final TestDB testDB : TestDB.getSupportedForBasename(Basename.INDEX_CODES)) {
-      Database db = open(testDB);
+      Database db = openMem(testDB);
 
       for(Table t : db) {
         for(Index index : t.getIndexes()) {
diff --git a/test/src/java/com/healthmarketscience/jackcess/MemFileChannelTest.java b/test/src/java/com/healthmarketscience/jackcess/MemFileChannelTest.java
new file mode 100644
index 0000000..6fa0425
--- /dev/null
+++ b/test/src/java/com/healthmarketscience/jackcess/MemFileChannelTest.java
@@ -0,0 +1,147 @@
+/*
+Copyright (c) 2012 James Ahlborn
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
+USA
+*/
+
+package com.healthmarketscience.jackcess;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
+import java.nio.channels.NonWritableChannelException;
+import java.util.Arrays;
+
+import junit.framework.TestCase;
+
+/**
+ *
+ * @author James Ahlborn
+ */
+public class MemFileChannelTest extends TestCase 
+{
+
+  public MemFileChannelTest(String name) {
+    super(name);
+  }
+
+  public void testReadOnlyChannel() throws Exception
+  {
+    File testFile = new File("test/data/V1997/compIndexTestV1997.mdb");
+    MemFileChannel ch = MemFileChannel.newChannel(testFile, "r");
+    assertEquals(testFile.length(), ch.size());
+    assertEquals(0L, ch.position());
+
+    try {
+      ByteBuffer bb = ByteBuffer.allocate(1024);
+      ch.write(bb);
+      fail("NonWritableChannelException should have been thrown");
+    } catch(NonWritableChannelException ignored) {
+      // success
+    }
+    
+    try {
+      ch.truncate(0L);
+      fail("NonWritableChannelException should have been thrown");
+    } catch(NonWritableChannelException ignored) {
+      // success
+    }
+    
+    try {
+      ch.transferFrom(null, 0L, 10L);
+      fail("NonWritableChannelException should have been thrown");
+    } catch(NonWritableChannelException ignored) {
+      // success
+    }
+
+    assertEquals(testFile.length(), ch.size());
+    assertEquals(0L, ch.position());
+
+    ch.close();
+  }
+
+  public void testChannel() throws Exception
+  {
+    ByteBuffer bb = ByteBuffer.allocate(1024);
+
+    MemFileChannel ch = MemFileChannel.newChannel();
+    assertTrue(ch.isOpen());
+    assertEquals(0L, ch.size());
+    assertEquals(0L, ch.position());
+    assertEquals(-1, ch.read(bb));
+    
+    ch.close();
+
+    assertFalse(ch.isOpen());
+
+    File testFile = new File("test/data/V1997/compIndexTestV1997.mdb");
+    ch = MemFileChannel.newChannel(testFile, "r");
+    assertEquals(testFile.length(), ch.size());
+    assertEquals(0L, ch.position());
+
+    MemFileChannel ch2 = MemFileChannel.newChannel();
+    ch.transferTo(ch2);
+    ch2.force(true);
+    assertEquals(testFile.length(), ch2.size());
+    assertEquals(testFile.length(), ch2.position());
+
+    long trucSize = ch2.size()/3;
+    ch2.truncate(trucSize);
+    assertEquals(trucSize, ch2.size());
+    assertEquals(trucSize, ch2.position());
+    ch2.position(0L);
+    copy(ch, ch2, bb);
+
+    File tmpFile = File.createTempFile("chtest_", ".dat");
+    tmpFile.deleteOnExit();
+    FileChannel fc = new RandomAccessFile(tmpFile, "rw").getChannel();
+
+    copy(ch2, fc, bb);
+
+    fc.close();
+
+    assertEquals(testFile.length(), tmpFile.length());
+
+    assertTrue(Arrays.equals(DatabaseTest.toByteArray(testFile),
+                             DatabaseTest.toByteArray(tmpFile)));
+
+    ch2.truncate(0L);
+    assertTrue(ch2.isOpen());
+    assertEquals(0L, ch2.size());
+    assertEquals(0L, ch2.position());
+    assertEquals(-1, ch2.read(bb));
+
+    ch2.close();
+    assertFalse(ch2.isOpen());
+  }
+
+  private static void copy(FileChannel src, FileChannel dst, ByteBuffer bb)
+    throws IOException
+  {
+    src.position(0L);
+    while(true) {
+      bb.clear();
+      if(src.read(bb) < 0) {
+        break;
+      }
+      bb.flip();
+      dst.write(bb);
+    }
+  }
+
+}