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27 lines
1.4 KiB
ReStructuredText
27 lines
1.4 KiB
ReStructuredText
Introduction
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============
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.. note:: This tutorial extends the CorDapp built during the :doc:`Hello, World tutorial <hello-world-index>`. You can
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download the final version of the CorDapp produced in that tutorial for
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`Java <https://github.com/joeldudleyr3/tutorials/tree/master/Tut1Java>`_ or
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`Kotlin <https://github.com/joeldudleyr3/tutorials/tree/master/Tut1Kotlin>`_.
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In the Hello, World tutorial, we built a CorDapp allowing us to model IOUs on ledger. Our CorDapp was made up of three
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elements:
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* An ``IOUState``, representing IOUs on the ledger
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* An ``IOUContract``, controlling the evolution of IOUs over time
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* An ``IOUFlow``, orchestrating the process of agreeing the creation of an IOU on-ledger
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However, in our original CorDapp, only the IOU's lender was required to sign transactions issuing IOUs. The borrower
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had no say in whether the issuance of the IOU was a valid ledger update or not.
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In this tutorial, we'll update our code so that the lender requires the borrower's agreement before they can issue an
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IOU onto the ledger. We'll need to make two changes:
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* The ``IOUContract`` will need to be updated so that transactions involving an ``IOUState`` will require the borrower's
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signature (as well as the lender's) to become valid ledger updates
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* The ``IOUFlow`` will need to be updated to allow for the gathering of the borrower's signature
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We'll start by updating the contract.
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