Package convex.core

Class Belief

java.lang.Object

convex.core.data.AObject

convex.core.data.ACell

convex.core.data.ACountable<E>

convex.core.data.ADataStructure<MapEntry<K,V>>

convex.core.data.AMap<Keyword,ACell>

convex.core.data.ARecord

convex.core.Belief

All Implemented Interfaces:

IValidated, IWriteable, Map<Keyword,ACell>

public class Belief
extends ARecord

Class representing a Peer's view of the overall network consensus state. Belief is immutable, and is designed to be independent of any particular Peer so that it can be efficiently merged towards consensus. Belief can be merged with other Beliefs from the perspective of a Peer. This property is fundamental to the Convex consensus algorithm. "Sorry to be a wet blanket. Writing a description for this thing for general audiences is bloody hard. There's nothing to relate it to." – Satoshi Nakamoto

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K extends Object,V extends Object>

Field Summary

Fields inherited from class convex.core.data.ARecord

DEFAULT_VALUE, format

Fields inherited from class convex.core.data.ADataStructure

count

Fields inherited from class convex.core.data.ACell

cachedRef, EMPTY_ARRAY

Fields inherited from class convex.core.data.AObject

encoding

Method Summary

Modifier and Type	Method	Description
static <V> double	computeVote(HashMap<V,Double> m)	Computes the total vote for all entries in a HashMap
static AVector<Block>	computeWinningOrder(HashMap<Order,Double> stakedOrders, long consensusPoint, double initialTotalStake)	Compute the new winning Order for this Peer, including any new blocks encountered
static Belief	create(AKeyPair kp, Order order)	Create a Belief with a single order signed by the given key pair, using initial timestamp.
static Belief	createSingleOrder(AKeyPair kp)	Create a Belief with a single empty order.
int	encode(byte[] bs, int pos)	Writes this Cell's encoding to a byte array, including a tag byte which will be written first
boolean	equals(Belief a)	Tests if this Belief is equal to another
boolean	equals(AMap<Keyword,ACell> a)	Checks this map for equality with another map.
int	estimatedEncodingSize()	Estimate the encoded data size for this Cell.
ACell	get(ACell k)	Gets the record field content for a given key, or null if not found.
Order	getOrder(AccountKey address)	Gets the current Order for a given Address within this Belief.
BlobMap<AccountKey,SignedData<Order>>	getOrders()	Get the map of orders for this Belief
byte	getTag()	Gets the tag byte for this record type.
long	getTimestamp()	Returns the timestamp of this Belief.
static Belief	initial()	Gets an empty Belief
Belief	merge(MergeContext mc, Belief... beliefs)	The Belief merge function
static double	prepareStakedOrders(AMap<AccountKey,SignedData<Order>> peerOrders, HashMap<AccountKey,Double> peerStakes, HashMap<Order,Double> dest)	Compute the total stake for every distinct Order seen.
static Belief	read(ByteBuffer bb)	Read a Belief from a ByteBuffer.
protected Belief	updateAll(ACell[] newVals)	Updates all values in this record, in declared field order.
void	validateCell()	Validates the local structure and invariants of this cell.
Belief	withOrders(BlobMap<AccountKey,SignedData<Order>> newOrders)	Updates this Belief with a new set of Chains for each peer address

Methods inherited from class convex.core.data.ARecord

accumulateEntrySet, accumulateKeySet, accumulateValues, assoc, assocEntry, containsKey, containsValue, dissoc, dissoc, empty, encodeRaw, entryAt, entrySet, equalsKeys, forEach, get, getEntry, getEntryByHash, getFormat, getKeyRefEntry, getKeys, getRef, getRefCount, getType, getValuesArray, isCanonical, isCVMValue, keySet, print, reduceEntries, reduceValues, toCanonical, toHashMap, updateRefs, values

Methods inherited from class convex.core.data.AMap

clear, conj, containsKey, containsKeyRef, entryVector, equals, filterValues, get, get, getElementRef, put, putAll, remove

Methods inherited from class convex.core.data.ADataStructure

conjAll, count, isEmpty, size

Methods inherited from class convex.core.data.ACell

announce, announce, attachMemorySize, attachRef, cachedEncoding, cachedHash, calcMemorySize, createAnnounced, createEncoding, createPersisted, createPersisted, createRef, equals, getChildRefs, getEncoding, getEncodingLength, getHash, getMemorySize, getRef, hashCode, isEmbedded, toString, validate, write

Methods inherited from class convex.core.data.AObject

attachEncoding, print

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, equals, getOrDefault, hashCode, isEmpty, merge, putIfAbsent, remove, replace, replace, replaceAll, size

Method Details

get

public ACell get(ACell k)

Description copied from class: ARecord

Gets the record field content for a given key, or null if not found.

Specified by:

get in class ARecord

Parameters:

k - Key to look up in this record

Returns:

Field value for the given key

updateAll

protected Belief updateAll(ACell[] newVals)

Description copied from class: ARecord

Updates all values in this record, in declared field order. Returns this if all values are identical.

Specified by:

updateAll in class ARecord

Parameters:

newVals - New values to replace current

Returns:

Updated Record

initial

public static Belief initial()

Gets an empty Belief

Returns:

Empty Belief

create

public static Belief create(AKeyPair kp,
 Order order)

Create a Belief with a single order signed by the given key pair, using initial timestamp.

Parameters:

kp - Peer Key pair with which to sign the order.

order - Order of blocks that the Peer is proposing

Returns:

new Belief representing the isolated belief of a single Peer.

createSingleOrder

public static Belief createSingleOrder(AKeyPair kp)

Create a Belief with a single empty order. USeful for Peer startup.

Parameters:

kp - Keypair for Peer

Returns:

New Belief

merge

public Belief merge(MergeContext mc,
 Belief... beliefs)
             throws BadSignatureException,
InvalidDataException

The Belief merge function

Parameters:

mc - MergeContext for Belief Merge

beliefs - An array of Beliefs. May contain nulls, which will be ignored.

Returns:

The updated merged belief, or the same Belief if there is no change.

Throws:

BadSignatureException - In case of a bad signature

InvalidDataException - In case of invalid data

computeWinningOrder

public static AVector<Block> computeWinningOrder(HashMap<Order,Double> stakedOrders,
 long consensusPoint,
 double initialTotalStake)

Compute the new winning Order for this Peer, including any new blocks encountered

Parameters:

stakedOrders - Amount of stake on each distinct Order

consensusPoint - Current consensus point

initialTotalStake - Total stake under consideration

Returns:

Vector of Blocks in wiing Order

computeVote

public static <V> double computeVote(HashMap<V,Double> m)

Computes the total vote for all entries in a HashMap

Type Parameters:

V - The type of values used as keys in the HashMap

Parameters:

m - A map of values to votes

Returns:

The total voting stake

prepareStakedOrders

public static double prepareStakedOrders(AMap<AccountKey,SignedData<Order>> peerOrders,
 HashMap<AccountKey,Double> peerStakes,
 HashMap<Order,Double> dest)

Compute the total stake for every distinct Order seen. Stores results in a map of Orders to staked value.

Parameters:

peerOrders - A map of peer addresses to signed proposed Orders

peerStakes - A map of peers addresses to weighted stakes for each peer

dest - Destination hashmap to store the stakes for each Order

Returns:

The total stake of all chains among peers under consideration

withOrders

public Belief withOrders(BlobMap<AccountKey,SignedData<Order>> newOrders)

Updates this Belief with a new set of Chains for each peer address

Parameters:

newOrders - New map of peer keys to Orders

Returns:

The updated belief, or the same Belief if no change.

encode

public int encode(byte[] bs,
 int pos)

Description copied from class: ACell

Writes this Cell's encoding to a byte array, including a tag byte which will be written first

Specified by:

encode in interface IWriteable

Specified by:

encode in class ACell

Parameters:

bs - A byte array to which to write the encoding

pos - The offset into the byte array

Returns:

New position after writing

estimatedEncodingSize

public int estimatedEncodingSize()

Description copied from interface: IWriteable

Estimate the encoded data size for this Cell. Used for quickly sizing buffers. Implementations should try to return a size that is likely to contain the entire object when represented in binary format, including the tag byte.

Specified by:

estimatedEncodingSize in interface IWriteable

Overrides:

estimatedEncodingSize in class ARecord

Returns:

The estimated size for the binary representation of this object.

read

public static Belief read(ByteBuffer bb)
                   throws BadFormatException

Read a Belief from a ByteBuffer. Assumes tag already read.

Parameters:

bb - ByteBuffer to read from

Returns:

Belief instance

Throws:

BadFormatException - If encoding is invalid

getTag

public byte getTag()

Description copied from class: ARecord

Gets the tag byte for this record type. The Tag is the byte used to identify the record in the binary encoding.

Specified by:

getTag in class ARecord

Returns:

Record tag byte

getOrder

public Order getOrder(AccountKey address)

Gets the current Order for a given Address within this Belief.

Parameters:

address - Address of peer

Returns:

The chain for the peer within this Belief, or null if noy found.

getOrders

public BlobMap<AccountKey,SignedData<Order>> getOrders()

Get the map of orders for this Belief

Returns:

Orders map

validateCell

public void validateCell()
                  throws InvalidDataException

Description copied from class: ACell

Validates the local structure and invariants of this cell. Called by validate() super implementation. Should validate directly contained data, but should not validate all other structure of this cell. In particular, should not traverse potentially missing child Refs.

Specified by:

validateCell in class ACell

Throws:

InvalidDataException - If the Cell is invalid

getTimestamp

public long getTimestamp()

Returns the timestamp of this Belief. A Belief should have a new timestamp if and only if the Peer incorporates new information.

Returns:

Timestamp of belief

equals

public boolean equals(AMap<Keyword,ACell> a)

Description copied from class: AMap

Checks this map for equality with another map. In general, maps should be considered equal if they have the same canonical representation, i.e. the same hash value. Subclasses may override this this they have a more efficient equals implementation or a more specific definition of equality.

Specified by:

equals in class AMap<Keyword,ACell>

Parameters:

a - Map to compare with

Returns:

true if maps are equal, false otherwise.

equals

public boolean equals(Belief a)

Tests if this Belief is equal to another

Parameters:

a - Belief to compare with

Returns:

true if equal, false otherwise