Aave Java SDK

prerequisite

• add JDK 'azul-16' as the project sdk
• have maven installed
• get an infura goerli or kovan test node
• have a goerli or kovan testnet wallet (can easily be gotten from metamask)
• and load with some test eth.
• look in the test to understand how to use.

Installation

just clone and mvn install from the terminal to add the web3j dependency then run the main in app.java

Look in the pom.xml to understand the dependency and the plugin.

###Todo

• get the solidity contracts of aave into the project
• get web3j plugin to work
• if you run the command mvn web3j:generate-sources in the terminal you'll get an error that's the plugin, it needs to be fixed for the following to work.

[

• use web3j convert the .sol contracts to .java wrapper classes
• get secret keys for aave if any and access deployed contract methods

] ###Current

• gotten the aave rpc node
• web3j dependency can connect to the aave rpc node
• The error in number three above has been resolved we left with finding a way to get the solidity contracts and create the wrapper classes.

##Known AAVE RPC nodes

https://eth-mainnet.alchemyapi.io/v2/demo just get a testnet address from infura and you are good to go. #Update

• wrapper classes have been created using the v2 .sol contracts.

• attempting to deposit on lending pool.

• we require an approve method for deposit to go through still finding away around that. ###lending pool contract

• deposit(String reserve,BigInteger amount,String onBehalfOf,BigInteger referralCode)

• please once again look in the test to understand how to use.

How to use

Lending Pool V2

• deposit
• borrow
• repay
• withdraw
• swapBorrowRateMode
• setUsageAsCollateral
• liquidationCall
• swapCollateral
• repayWithCollateral

Lending Pool V2

Object that contains all the necessary methods to create Aave V2 lending pool transactions

deposit

Deposits the underlying asset into the reserve. For every token that is deposited, a corresponding amount of aTokens is minted

Sample Code

/*
- @param `assetAddress` The ethereum address of the reserve asset
- @param `lendingPoolAddressProvider` lending pool address provider 
- @param `amount` The amount to be deposited, in human readable units as strings (e.g. 25000000000 ETH) 
- @param `interestRateMode`//Whether the borrow will incur a stable (InterestRate.Stable) or variable (InterestRate.Variable) interest rate
- @param `onBehalfOf` The ethereum address for which user is depositing.
*/
class LendingPoolTest {
    //check that you are on the right network 
    //NB kovan and other test nets are deprecated use Goerli
    String nodeUrl 
        = "https://goerli.infura.io/v3/<replace with your infura key>";
    String privateKey 
        = "<replace with your private key to your wallet>";
    
    private AaveConnect connection = new AaveConnect(privateKey, nodeUrl);
    
    private LendingPool lendingPool = new LendingPool(connection, lendingPoolAddressProvider, gasFee, gasLimit);

    /* rest of your code... constructor...*/

    void lendingPoolDeposit() {
        Erc20 erc20 = new Erc20(connection, amount, assetAddress);

        try {
            erc20.approve(amount);
            TransactionReceipt depositReceipt = lendingPool.deposit(amount, assetAddress, onBehalfOf);
        } catch (Exception e) {
            e.printStackTrace();
        }
       
    }
}

borrow

Borrow an amount of reserve asset.

User must have a collaterised position (i.e. aTokens in their wallet)

Sample Code

/*
- @param `assetAddress` The ethereum address of the reserve asset 
- @param `amount` The amount to be borrowed, in human readable units as strings (e.g. 25000000000 ETH) 
- @param `interestRateMode`//Whether the borrow will incur a stable (InterestRate.Stable) or variable (InterestRate.Variable) interest rate
- @param `lendingPoolAddressProvider` lending pool address provider 
- @param `onBehalfOf` The ethereum address for which user is borrowing. It will default to the user address 
*/

class LendingPoolTest {
    String nodeUrl
        = "https://goerli.infura.io/v3/<replace with your infura key>";
    String privateKey
        = "<replace with your private key to your wallet>";

    private AaveConnect connection = new AaveConnect(privateKey, nodeUrl);

    private LendingPool lendingPool = new LendingPool(connection, lendingPoolAddressProvider, gasFee, gasLimit);

    /* rest of your code... constructor...*/
    
    void lendingPoolWithdraw() {

        try {
            TransactionReceipt borrowReceipt =  lendingPool.borrow(amount, assetAddress, onBehalfOf);
        } catch (Exception e) {
            e.printStackTrace();
        }
     }
}

repay

Repays a borrow on the specific reserve, for the specified amount (or for the whole amount, if (-1) is specified). the target user is defined by onBehalfOf. If there is no repayment on behalf of another account, onBehalfOf must be equal to user

If the user is not approved, an approval transaction will also be returned

Sample Code

/*
- @param `assetAddress` The ethereum address of the reserve asset 
- @param `amount` The amount to be borrowed, in human readable units as strings (e.g. 25000000000 ETH) 
- @param `interestRateMode`//Whether the borrow will incur a stable (InterestRate.Stable) or variable (InterestRate.Variable) interest rate
- @param `lendingPoolAddressProvider` lending pool address provider 
- @param `onBehalfOf` The ethereum address for which user is borrowing. It will default to the user address 
*/

class LendingPoolTest {
    String nodeUrl
        = "https://goerli.infura.io/v3/<replace with your infura key>";
    String privateKey
        = "<replace with your private key to your wallet>";

    private AaveConnect connection = new AaveConnect(privateKey, nodeUrl);

    private LendingPool lendingPool = new LendingPool(connection, lendingPoolAddressProvider, gasFee, gasLimit);

    /* rest of your code... constructor...*/
    
    void lendingPoolWithdraw() {

        try {
            TransactionReceipt repayReceipt =  lendingPool.repay(amount, assetAddress, onBehalfOf);
        } catch (Exception e) {
            e.printStackTrace();
        }
     }
}

withdraw

Withdraws the underlying asset of an aToken asset.

Sample Code

/*
- @param `assetAddress` The ethereum address of the reserve asset 
- @param `amount` The amount to be withdrawn, in human readable units as strings (e.g. 25000000000 ETH) 
- @param `interestRateMode`//Whether the borrow will incur a stable (InterestRate.Stable) or variable (InterestRate.Variable) interest rate
- @param `lendingPoolAddressProvider` lending pool address provider 
- @param `toAddress` The ethereum address for which user is borrowing. It will default to the user address 
*/

class LendingPoolTest {
    String nodeUrl
        = "https://goerli.infura.io/v3/<replace with your infura key>";
    String privateKey
        = "<replace with your private key to your wallet>";

    private AaveConnect connection = new AaveConnect(privateKey, nodeUrl);

    private LendingPool lendingPool = new LendingPool(connection, lendingPoolAddressProvider, gasFee, gasLimit);

    /* rest of your code... constructor...*/

    void lendingPoolWithdraw() {

        try {
            TransactionReceipt withDrawReceipt =  lendingPool.withdraw(amount, assetAddress, toAdderess);
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}

swapBorrowRateMode

Borrowers can use this function to swap between stable and variable borrow rate modes.

Sample Code

/*
- @param `assetAddress` The address of the reserve on which the user borrowed 
- @param `mode` //Whether the borrow will incur a stable (InterestRate.Stable) or variable (InterestRate.Variable) interest rate which is either "1" for stable or "2" for variable
*/
class LendingPoolTest {
    String nodeUrl
        = "https://goerli.infura.io/v3/<replace with your infura key>";
    String privateKey
        = "<replace with your private key to your wallet>";

    private AaveConnect connection = new AaveConnect(privateKey, nodeUrl);

    private LendingPool lendingPool = new LendingPool(connection, lendingPoolAddressProvider, gasFee, gasLimit);

    /* rest of your code... constructor...*/

    void swapBorrowRate() {
        try {
            TransactionReceipt swapBorrowRateReceipt =  lendingPool.swapBorrowRate(assetAddress, mode);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}