Checksummer (JHOVE - JSTOR/Harvard Object Validation Environment 1.16.0 API)

java.lang.Object
- edu.harvard.hul.ois.jhove.Checksummer

All Implemented Interfaces:

Checksum
```
public class Checksummer
extends Object
implements Checksum
```
The Checksummer class encapsulates the calculation of the CRC32, MD5, and SHA-1 checksums.

Field Summary

Fields
Modifier and Type Field and Description

protected long _nByte
Byte count.

Fields
Modifier and Type	Field and Description
`protected long`	`_nByte` Byte count.

Constructor Summary

Constructors
Constructor and Description

Checksummer()
Creates a Checksummer, with instances of each of CRC32, MD5 MessageDigest, and SHA-1 MessageDigest.

Constructors
Constructor and Description
`Checksummer()` Creates a Checksummer, with instances of each of CRC32, MD5 MessageDigest, and SHA-1 MessageDigest.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`String`	`getCRC32()` Returns the value of the CRC32 as a hex string.
`String`	`getMD5()` Returns the value of the MD5 digest as a hex string.
`String`	`getSHA1()` Returns the value of the SHA-1 digest as a hex string.
`long`	`getValue()` getValue is required by the Checksum interface, but we can return only one of the three values.
`void`	`reset()` Resets all checksums and the byte count to their initial values.
`void`	`update(byte b)` Updates the checksum with the argument.
`void`	`update(byte[] b)` Updates the checksum with the argument.
`void`	`update(byte[] b, int off, int len)` Updates the checksum with the argument.
`void`	`update(int b)` Updates the checksum with the argument.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - _nByte
```
protected long _nByte
```
    Byte count.
- Constructor Detail
  - Checksummer
```
public Checksummer()
```
    Creates a Checksummer, with instances of each of CRC32, MD5 MessageDigest, and SHA-1 MessageDigest. If one or both of the MessageDigests aren't supported on the current platform, they are left as null.
    
    See Also:
    
    CRC32, MessageDigest
- Method Detail
  - reset
```
public void reset()
```
    Resets all checksums and the byte count to their initial values.
    
    Specified by:
    
    reset in interface Checksum
  - getValue
```
public long getValue()
```
    getValue is required by the Checksum interface, but we can return only one of the three values. We return the CRC32 value, since that's the one which is guaranteed to be available.
    
    Specified by:
    
    getValue in interface Checksum
  - update
```
public void update(byte b)
```
    Updates the checksum with the argument. Called when a signed byte is available.
  - update
```
public void update(int b)
```
    Updates the checksum with the argument. Called when an unsigned byte is available.
    
    Specified by:
    
    update in interface Checksum
  - update
```
public void update(byte[] b)
```
    Updates the checksum with the argument. Called when a byte array is available.
  - update
```
public void update(byte[] b,
                   int off,
                   int len)
```
    Updates the checksum with the argument. Called when a byte array is available.
    
    Specified by:
    
    update in interface Checksum
  - getCRC32
```
public String getCRC32()
```
    Returns the value of the CRC32 as a hex string.
  - getMD5
```
public String getMD5()
```
    Returns the value of the MD5 digest as a hex string. Returns null if the digest is not available.
  - getSHA1
```
public String getSHA1()
```
    Returns the value of the SHA-1 digest as a hex string. Returns null if the digest is not available.

Class Checksummer

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

_nByte

Constructor Detail

Checksummer

Method Detail

reset

getValue

update

update

update

update

getCRC32

getMD5

getSHA1