com.github.mathiewz.blockchain

Class Block<T extends Serializable>

java.lang.Object

com.github.mathiewz.blockchain.Block<T>

Type Parameters:

T - The class of the data.

All Implemented Interfaces:

Serializable, Comparable<Block<T>>, Iterable<Block<T>>

public class Block<T extends Serializable>
extends Object
implements Iterable<Block<T>>, Comparable<Block<T>>, Serializable

A block containing some data. The data is stored in an object T It is chained with other blocks.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
Block(T data) Create the first block of the chain.
Block(T data, Block<T> previous) Create a new block in the chain.

Method Summary

Modifier and Type	Method and Description
static <T extends Serializable> int	compare(Block<T> firstChain, Block<T> secondChain) Compare two blocks and return the best one.
int	compareTo(Block<T> o)
boolean	equals(Object obj)
T	getData() Return the data contained in the block.
Block<T>	getPrevious() Return the previous block in the chain.
int	hashCode()
boolean	isValid() Check if the block is valid
boolean	isWholeChainValid() Check if the whole chain is valid
Iterator<Block<T>>	iterator()
java.util.stream.Stream<Block<T>>	stream() Returns a sequential Stream with this blockchain as its source.
String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

Block

public Block(T data)

Create the first block of the chain.

Parameters:

data - The data contained in the block.

Block

public Block(T data,
             Block<T> previous)

Create a new block in the chain.

Parameters:

data - The data contained in the block.

previous - The previous block in the chain.

Method Detail

getData

public T getData()

Return the data contained in the block.

Returns:

getPrevious

public Block<T> getPrevious()

Return the previous block in the chain. If the current block is the first, it return itself.

Returns:

isValid

public boolean isValid()

Check if the block is valid

Returns:

true if the data in the block are not altered

stream

public java.util.stream.Stream<Block<T>> stream()

Returns a sequential Stream with this blockchain as its source.

Returns:

a sequential Stream with this blockchain as its source.

isWholeChainValid

public boolean isWholeChainValid()

Check if the whole chain is valid

Returns:

true if all the previous block to the index 0 are valid

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

iterator

public Iterator<Block<T>> iterator()

Specified by:

iterator in interface Iterable<Block<T extends Serializable>>

toString

public String toString()

Overrides:

toString in class Object

compareTo

public int compareTo(Block<T> o)

Specified by:

compareTo in interface Comparable<Block<T extends Serializable>>

compare

public static <T extends Serializable> int compare(Block<T> firstChain,
                                                   Block<T> secondChain)

Compare two blocks and return the best one. A block is better if it is valid and the bigger its index is.

Parameters:

firstChain - the first blockchain to compare

secondChain - the second blockchain to compare

Returns:

a negative value secondChain is better, a positive value if the firstChain is better, and 0 if it's not possible to determine which is the better chain.