Example usage for org.apache.cassandra.io.util RandomAccessReader readFully

Introduction

In this page you can find the example usage for org.apache.cassandra.io.util RandomAccessReader readFully.

Prototype

@Override
    public void readFully(byte[] b) throws IOException 

Source Link

Usage

From source file:com.fullcontact.cassandra.io.util.BufferedRandomAccessFileTest.java

License:Apache License

@Test
public void testReadAndWrite() throws Exception {
    SequentialWriter w = createTempFile("braf");

    // writting string of data to the file
    byte[] data = "Hello".getBytes();
    w.write(data);//from  w w  w  . j a  v a  2s  . c  o  m
    assertEquals(data.length, w.length());
    assertEquals(data.length, w.getFilePointer());

    w.sync();

    // reading small amount of data from file, this is handled by initial buffer
    RandomAccessReader r = RandomAccessReader.open(w, fs);

    byte[] buffer = new byte[data.length];
    assertEquals(data.length, r.read(buffer));
    assertTrue(Arrays.equals(buffer, data)); // we read exactly what we wrote
    assertEquals(r.read(), -1); // nothing more to read EOF
    assert r.bytesRemaining() == 0 && r.isEOF();

    r.close();

    // writing buffer bigger than page size, which will trigger reBuffer()
    byte[] bigData = new byte[RandomAccessReader.DEFAULT_BUFFER_SIZE + 10];

    for (int i = 0; i < bigData.length; i++)
        bigData[i] = 'd';

    long initialPosition = w.getFilePointer();
    w.write(bigData); // writing data
    assertEquals(w.getFilePointer(), initialPosition + bigData.length);
    assertEquals(w.length(), initialPosition + bigData.length); // file size should equals to last position

    w.sync();

    r = RandomAccessReader.open(w, fs); // re-opening file in read-only mode

    // reading written buffer
    r.seek(initialPosition); // back to initial (before write) position
    data = new byte[bigData.length];
    long sizeRead = 0;
    for (int i = 0; i < data.length; i++) {
        data[i] = (byte) r.read();
        sizeRead++;
    }

    assertEquals(sizeRead, data.length); // read exactly data.length bytes
    assertEquals(r.getFilePointer(), initialPosition + data.length);
    assertEquals(r.length(), initialPosition + bigData.length);
    assertTrue(Arrays.equals(bigData, data));
    assertTrue(r.bytesRemaining() == 0 && r.isEOF()); // we are at the of the file

    // test readBytes(int) method
    r.seek(0);
    ByteBuffer fileContent = r.readBytes((int) w.length());
    assertEquals(fileContent.limit(), w.length());
    assert ByteBufferUtil.string(fileContent).equals("Hello" + new String(bigData));

    // read the same buffer but using readFully(int)
    data = new byte[bigData.length];
    r.seek(initialPosition);
    r.readFully(data);
    assert r.bytesRemaining() == 0 && r.isEOF(); // we should be at EOF
    assertTrue(Arrays.equals(bigData, data));

    // try to read past mark (all methods should return -1)
    data = new byte[10];
    assertEquals(r.read(), -1);
    assertEquals(r.read(data), -1);
    assertEquals(r.read(data, 0, data.length), -1);

    // test read(byte[], int, int)
    r.seek(0);
    data = new byte[20];
    assertEquals(15, r.read(data, 0, 15));
    assertTrue(new String(data).contains("Hellodddddddddd"));
    for (int i = 16; i < data.length; i++) {
        assert data[i] == 0;
    }

    w.close();
    r.close();
}

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