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Provided Code

public class Gizmo
{
    public String getMaker() { /* not shown */ }
    public boolean isElectronic() { /* not shown */ }
    public boolean equals(Object other) { /* not shown */ }
}

public class OnlinePurchaseManager
{
    private ArrayList purchases;
    /** Returns count of electronic Gizmos from the given maker. */
        public int countElectronicsByMaker(String maker) {
        /* part (a) */
    }
    /** Returns true if any two adjacent Gizmos in purchases are equivalent. */
        public boolean hasAdjacentEqualPair() {
        /* part (b) */
    }
}

Part A — 4 Points

Write countElectronicsByMaker: examine purchases and return the number of Gizmo objects that are both electronic (isElectronic() is true) and manufactured by maker.

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public int countElectronicsByMaker(String maker)
{
    int count = 0;
    for (Gizmo g : purchases)
    {
        if (g.isElectronic() && g.getMaker().equals(maker))
        {
            count++;
        }
    }
    return count;
}

Part B — 4 Points

Write hasAdjacentEqualPair: return true if any two adjacent Gizmo objects in purchases are equivalent (using the equals method of Gizmo). Return false if no adjacent equal pair exists or if purchases has fewer than 2 elements.

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public boolean hasAdjacentEqualPair()
{
    for (int i = 0; i < purchases.size() - 1; i++)
    {
        if (purchases.get(i).equals(purchases.get(i + 1)))
        {
            return true;
        }
    }
    return false;
}

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