luni/src/test/java/libcore/java/nio/channels/FileChannelTest.java

/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package libcore.java.nio.channels;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import libcore.io.IoUtils;

public class FileChannelTest extends junit.framework.TestCase {
    public void testReadOnlyByteArrays() throws Exception {
        ByteBuffer readOnly = ByteBuffer.allocate(1).asReadOnlyBuffer();
        File tmp = File.createTempFile("FileChannelTest", "tmp");

        // You can't read into a read-only buffer...
        FileChannel fc = new FileInputStream(tmp).getChannel();
        try {
            fc.read(readOnly);
            fail();
        } catch (IllegalArgumentException expected) {
        }
        try {
            fc.read(new ByteBuffer[] { readOnly });
            fail();
        } catch (IllegalArgumentException expected) {
        }
        try {
            fc.read(new ByteBuffer[] { readOnly }, 0, 1);
            fail();
        } catch (IllegalArgumentException expected) {
        }
        try {
            fc.read(readOnly, 0L);
            fail();
        } catch (IllegalArgumentException expected) {
        }
        fc.close();


        // But you can write from a read-only buffer...
        fc = new FileOutputStream(tmp).getChannel();
        fc.write(readOnly);
        fc.write(new ByteBuffer[] { readOnly });
        fc.write(new ByteBuffer[] { readOnly }, 0, 1);
        fc.write(readOnly, 0L);
        fc.close();
    }

    public void test_readv() throws Exception {
        File tmp = File.createTempFile("FileChannelTest", "tmp");
        FileChannel fc = new FileOutputStream(tmp).getChannel();
        fc.write(ByteBuffer.wrap("abcdABCD".getBytes("US-ASCII")));
        fc.close();
        // Check that both direct and non-direct buffers work.
        fc = new FileInputStream(tmp).getChannel();
        ByteBuffer[] buffers = new ByteBuffer[] { ByteBuffer.allocateDirect(4), ByteBuffer.allocate(4) };
        assertEquals(8, fc.read(buffers));
        fc.close();
        assertEquals(8, buffers[0].limit() + buffers[1].limit());
        byte[] bytes = new byte[4];
        buffers[0].flip();
        buffers[0].get(bytes);
        assertEquals("abcd", new String(bytes, "US-ASCII"));
        buffers[1].flip();
        buffers[1].get(bytes);
        assertEquals("ABCD", new String(bytes, "US-ASCII"));
    }

    public void test_writev() throws Exception {
        File tmp = File.createTempFile("FileChannelTest", "tmp");
        FileChannel fc = new FileOutputStream(tmp).getChannel();
        // Check that both direct and non-direct buffers work.
        ByteBuffer[] buffers = new ByteBuffer[] { ByteBuffer.allocateDirect(4), ByteBuffer.allocate(4) };
        buffers[0].put("abcd".getBytes("US-ASCII")).flip();
        buffers[1].put("ABCD".getBytes("US-ASCII")).flip();
        assertEquals(8, fc.write(buffers));
        fc.close();
        assertEquals(8, tmp.length());
        assertEquals("abcdABCD", new String(IoUtils.readFileAsString(tmp.getPath())));
    }

    public void test_append() throws Exception {
        File tmp = File.createTempFile("FileChannelTest", "tmp");
        FileOutputStream fos = new FileOutputStream(tmp, true);
        FileChannel fc = fos.getChannel();

        fc.write(ByteBuffer.wrap("hello".getBytes("US-ASCII")));
        fc.position(0);
        // The RI reports whatever position you set...
        assertEquals(0, fc.position());
        // ...but writes to the end of the file.
        fc.write(ByteBuffer.wrap(" world".getBytes("US-ASCII")));
        fos.close();

        assertEquals("hello world", new String(IoUtils.readFileAsString(tmp.getPath())));
    }
}