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Java example source code file (Ser.java)

This example Java source code file (Ser.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

big_money, bigdecimal, biginteger, bigmoney, currency_unit, currencyunit, deserialization, invalidobjectexception, ioexception, math, money, object, override, ser, streamcorruptedexception

The Ser.java Java example source code

/*
 *  Copyright 2009-present, Stephen Colebourne
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.joda.money;

import java.io.Externalizable;
import java.io.IOException;
import java.io.InvalidClassException;
import java.io.InvalidObjectException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.io.StreamCorruptedException;
import java.math.BigDecimal;
import java.math.BigInteger;

/**
 * A package scoped class used to manage serialization efficiently.
 * <p>
 * This class is mutable and intended for use by a single thread.
 */
final class Ser implements Externalizable {

    /** Type for BigMoney. */
    static final byte BIG_MONEY = 'B';
    /** Type for Money. */
    static final byte MONEY = 'M';
    /** Type for CurrencyUnit. */
    static final byte CURRENCY_UNIT = 'C';  // not in use yet

    /** The type. */
    private byte type;
    /** The data object. */
    private Object object;

    /**
     * Constructor for serialization.
     */
    public Ser() {
    }

    /**
     * Constructor for package.
     * 
     * @param type  the type
     * @param object  the object
     */
    Ser(byte type, Object object) {
        this.type = type;
        this.object = object;
    }

    //-----------------------------------------------------------------------
    /**
     * Outputs the data.
     *
     * @serialData One byte type code, then data specific to the type.
     * @param out  the output stream
     * @throws IOException if an error occurs
     */
    @Override
    public void writeExternal(ObjectOutput out) throws IOException {
        out.writeByte(type);
        switch (type) {
            case BIG_MONEY: {
                BigMoney obj = (BigMoney) object;
                writeBigMoney(out, obj);
                return;
            }
            case MONEY: {
                Money obj = (Money) object;
                writeBigMoney(out, obj.toBigMoney());
                return;
            }
            case CURRENCY_UNIT: {
                CurrencyUnit obj = (CurrencyUnit) object;
                writeCurrency(out, obj);
                return;
            }
        }
        throw new InvalidClassException("Joda-Money bug: Serialization broken");
    }

    private void writeBigMoney(ObjectOutput out, BigMoney obj) throws IOException {
        writeCurrency(out, obj.getCurrencyUnit());
        byte[] bytes = obj.getAmount().unscaledValue().toByteArray();
        out.writeInt(bytes.length);
        out.write(bytes);
        out.writeInt(obj.getScale());
    }

    private void writeCurrency(ObjectOutput out, CurrencyUnit obj) throws IOException {
        out.writeUTF(obj.getCode());
        out.writeShort(obj.getNumericCode());
        out.writeShort(obj.getDefaultFractionDigits());
    }

    /**
     * Outputs the data.
     *
     * @param in  the input stream
     * @throws IOException if an error occurs
     */
    @Override
    public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
        type = in.readByte();
        switch (type) {
            case BIG_MONEY: {
                object = readBigMoney(in);
                return;
            }
            case MONEY: {
                object = new Money(readBigMoney(in));
                return;
            }
            case CURRENCY_UNIT: {
                object = readCurrency(in);
                return;
            }
        }
        throw new StreamCorruptedException("Serialization input has invalid type");
    }

    private BigMoney readBigMoney(ObjectInput in) throws IOException {
        CurrencyUnit currency = readCurrency(in);
        byte[] bytes = new byte[in.readInt()];
        in.readFully(bytes);
        BigDecimal bd = new BigDecimal(new BigInteger(bytes), in.readInt());
        BigMoney bigMoney = new BigMoney(currency, bd);
        return bigMoney;
    }

    private CurrencyUnit readCurrency(ObjectInput in) throws IOException {
        String code = in.readUTF();
        CurrencyUnit singletonCurrency = CurrencyUnit.of(code);
        if (singletonCurrency.getNumericCode() != in.readShort()) {
            throw new InvalidObjectException("Deserialization found a mismatch in the numeric code for currency " + code);
        }
        if (singletonCurrency.getDefaultFractionDigits() != in.readShort()) {
            throw new InvalidObjectException("Deserialization found a mismatch in the decimal places for currency " + code);
        }
        return singletonCurrency;
    }

    /**
     * Returns the object that will replace this one.
     * 
     * @return the read object, should never be null
     */
    private Object readResolve() {
        return object;
    }

}

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