E - type of code-based enumerationpublic class OfpCodeBasedCodec<E extends OfpCodeBasedEnum> extends AbstractBitCodec<E>
The type parameter <E> is an enumeration class that implements
the set of code values, derived from OfpCodeBasedEnum. The code
values for the constants described by the enumeration class must be greater
than or equal to 0 and not exceed 31 for this codec to function correctly.
The code associated with the enumeration constant is used to indicate the corresponding position in the encoded bitmap for that constant. A value of 1 in the bitmap in the position determined by the constant code indicates that the flag is present.
For example, an enumeration constant has code value of 2. To determine if this constant is set in the bit map, a value of 1 is shifted left twice (1 << 2). If the bitmap has a 1 in this position, then the flag is present.
Suppose you a have set of codes encoded as bits in a field; in OpenFlow version 1.0:
0 (treated as 1 << 0)1 (treated as 1 << 1)2 (treated as 1 << 2)4 (treated as 1 << 4)5 (treated as 1 << 5)6 (treated as 1 << 6)7 (treated as 1 << 7)
private static final int[] MASKS = {
0x07, // 1.0 (0000 0111)
0x17, // 1.1 (0001 0111)
0x17, // 1.2 (0001 0111)
0xf5, // 1.3 (1111 0101)
};
The code-based enumeration class should be written something like this:
public enum FooBar implements OfpCodeEnum {}
FOO(0),
GOO(1),
ZOO(2),
BAR(4),
BAZ(5),
BOP(6),
BAM(7),
;
private int code;
FooBar(int code) {
this.code = code;
}
private static final int[] MASKS = {
0x07, // 1.0
0x17, // 1.1
0x17, // 1.2
0xf5, // 1.3
}
@Override
public int getCode(ProtocolVersion pv) {
return code;
}
// secret decoder ring
private static final OfpCodeBasedCodec<FooBar> CODEC =
new OfpCodeBasedCodec<FooBar>(MASKS, values);
// (javadocs go here)
public static Set<FooBar> decodeFlags(int bitmap, ProtocolVersion pv) {
return CODEC.decode(bitmap, pv);
}
// (javadocs go here)
public static int encodeFlags(Set<FooBar> flags, ProtocolVersion pv) {
return CODEC.encode(flags, pv);
}
flagSet, masks, NA_CODE| Constructor and Description |
|---|
OfpCodeBasedCodec(int[] masks,
E[] flagSet)
Constructs the codec, which squirrels away the bit masks and flag set
for use during the
AbstractBitCodec.encode(java.util.Set<E>, com.h3c.of.lib.ProtocolVersion) and AbstractBitCodec.decode(int, com.h3c.of.lib.ProtocolVersion) methods. |
| Modifier and Type | Method and Description |
|---|---|
protected boolean |
cannotBeMapped(int value)
This test should return true if the given value (code, or bit) cannot
be mapped into the bitmap; false if it is okay.
|
protected String |
formatValue(int value)
Returns the appropriate formatting of the value for an exception message.
|
protected int |
getBitToMap(E flag,
ProtocolVersion pv)
Given a flag and a protocol version, this method should return the
appropriate bit in the map that represents this flag.
|
protected int |
getValue(E flag,
ProtocolVersion pv)
Returns the value (bit, or code) from the given flag, for the
given version.
|
decode, disposeStorage, encode, initStoragepublic OfpCodeBasedCodec(int[] masks,
E[] flagSet)
AbstractBitCodec.encode(java.util.Set<E>, com.h3c.of.lib.ProtocolVersion) and AbstractBitCodec.decode(int, com.h3c.of.lib.ProtocolVersion) methods.
Note that, most of the time, the flag set should be
EnumClass.values().masks - the "valid bit position" masks; one for each
protocol versionflagSet - the set of flags to iterate over during decodeNullPointerException - if either parameter is nullIllegalArgumentException - if masks does not include a mask for
every protocol version or flagSet is not valid for this codecprotected int getValue(E flag, ProtocolVersion pv)
AbstractBitCodecgetValue in class AbstractBitCodec<E extends OfpCodeBasedEnum>flag - the flagpv - the protocol versionprotected boolean cannotBeMapped(int value)
AbstractBitCodeccannotBeMapped in class AbstractBitCodec<E extends OfpCodeBasedEnum>value - the value to testprotected String formatValue(int value)
AbstractBitCodecformatValue in class AbstractBitCodec<E extends OfpCodeBasedEnum>value - the valueprotected int getBitToMap(E flag, ProtocolVersion pv)
AbstractBitCodecgetBitToMap in class AbstractBitCodec<E extends OfpCodeBasedEnum>flag - the flagpv - the protocol versionCopyright © 2014. All Rights Reserved.