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AsymmetricFingerprintDialog / src / com.example.android.asymmetricfingerprintdialog / server /

Transaction.java

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/*
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 * Copyright (C) 2015 The Android Open Source Project
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 *
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 * Licensed under the Apache License, Version 2.0 (the "License");
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 * you may not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *
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 *      http://www.apache.org/licenses/LICENSE-2.0
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 *
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an "AS IS" BASIS,
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License
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 */
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package com.example.android.asymmetricfingerprintdialog.server;
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import java.io.ByteArrayOutputStream;
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import java.io.DataOutputStream;
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import java.io.IOException;
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import java.util.Objects;
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/**
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 * An entity that represents a single transaction (purchase) of an item.
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 */
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public class Transaction {
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    /** The unique ID of the item of the purchase */
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    private final Long mItemId;
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    /** The unique user ID who made the transaction */
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    private final String mUserId;
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    /**
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     * The random long value that will be also signed by the private key and verified in the server
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     * that the same nonce can't be reused to prevent replay attacks.
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     */
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    private final Long mClientNonce;
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    public Transaction(String userId, long itemId, long clientNonce) {
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        mItemId = itemId;
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        mUserId = userId;
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        mClientNonce = clientNonce;
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    }
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    public String getUserId() {
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        return mUserId;
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    }
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    public byte[] toByteArray() {
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        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
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        DataOutputStream dataOutputStream = null;
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        try {
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            dataOutputStream = new DataOutputStream(byteArrayOutputStream);
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            dataOutputStream.writeLong(mItemId);
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            dataOutputStream.writeUTF(mUserId);
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            dataOutputStream.writeLong(mClientNonce);
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            return byteArrayOutputStream.toByteArray();
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        } catch (IOException e) {
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            throw new RuntimeException(e);
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        } finally {
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            try {
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                if (dataOutputStream != null) {
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                    dataOutputStream.close();
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                }
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            } catch (IOException ignore) {
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            }
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            try {
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                byteArrayOutputStream.close();
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            } catch (IOException ignore) {
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            }
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        }
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    }
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    @Override
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    public boolean equals(Object o) {
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        if (this == o) {
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            return true;
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        }
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        if (o == null || getClass() != o.getClass()) {
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            return false;
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        }
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        Transaction that = (Transaction) o;
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        return Objects.equals(mItemId, that.mItemId) && Objects.equals(mUserId, that.mUserId) &&
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                Objects.equals(mClientNonce, that.mClientNonce);
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    }
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    @Override
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    public int hashCode() {
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        return Objects.hash(mItemId, mUserId, mClientNonce);
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    }
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}
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