Refactoring all markets related code

src/main/java/collectors/HousingMarketStats.java

@@ -2,6 +2,10 @@
 
 import housing.*;
 
+import markets.HouseBuyerRecord;
+import markets.HouseSaleRecord;
+import markets.HousingMarket;
+import markets.HousingMarketRecord;
 import org.apache.commons.math3.stat.descriptive.DescriptiveStatistics;
 
 /**************************************************************************************************
@@ -18,7 +22,7 @@ public class HousingMarketStats extends CollectorBase {
 	//------------------//
 
 	// General fields
-	private HousingMarket           market; // Declared HousingMarket so that it can accommodate both sale and rental markets
+	private HousingMarket market; // Declared HousingMarket so that it can accommodate both sale and rental markets
 	private Config                  config = Model.config; // Passes the Model's configuration parameters object to a private field
 
 	// Variables computed at initialisation
@@ -169,15 +173,15 @@ public void preClearingRecord() {
         bidPrices = new double[nBuyers];
 
 
-        // Record bid prices and their average
+        // Record submitBid prices and their average
         int i = 0;
         for(HouseBuyerRecord bid : market.getBids()) {
             sumBidPrices += bid.getPrice();
             bidPrices[i] = bid.getPrice();
             ++i;
         }
 
-        // Record offer prices, their average, and the number of empty and new houses
+        // Record submitOffer prices, their average, and the number of empty and new houses
         i = 0;
         for(HousingMarketRecord sale : market.getOffersPQ()) {
             sumOfferPrices += sale.getPrice();

src/main/java/collectors/MicroDataRecorder.java

@@ -1,6 +1,10 @@
 package collectors;
 
 import housing.*;
+import markets.HouseBuyerRecord;
+import markets.HouseSaleMarket;
+import markets.HouseSaleRecord;
+import markets.HousingMarket;
 
 import java.io.FileNotFoundException;
 import java.io.PrintWriter;

src/main/java/collectors/RentalMarketStats.java

@@ -1,6 +1,8 @@
 package collectors;
 
 import housing.*;
+import markets.HouseRentalMarket;
+import markets.HouseSaleRecord;
 
 import java.util.Arrays;
 

src/main/java/housing/Config.java

@@ -36,7 +36,7 @@ public class Config {
     public int N_QUALITY;                   // Number of quality bands for houses
 
     // Housing market parameters
-    int DAYS_UNDER_OFFER;                       // Time (in days) that a house remains under offer
+    int DAYS_UNDER_OFFER;                       // Time (in days) that a house remains under submitOffer
     double BIDUP;                               // Smallest proportional increase in price that can cause a gazump
     public double MARKET_AVERAGE_PRICE_DECAY;   // Decay constant for the exponential moving average of sale prices
     public double INITIAL_HPI;                  // Initial housing price index
@@ -172,7 +172,7 @@ public class Config {
     public class DerivedParams {
         // Housing market parameters
         public int HPI_RECORD_LENGTH;   // Number of months to record HPI (to compute price growth at different time scales)
-        double MONTHS_UNDER_OFFER;      // Time (in months) that a house remains under offer
+        double MONTHS_UNDER_OFFER;      // Time (in months) that a house remains under submitOffer
         double T;                       // Characteristic number of data-points over which to average market statistics
         public double E;                // Decay constant for averaging days on market (in transactions)
         public double G;                // Decay constant for averageListPrice averaging (in transactions)

src/main/java/housing/Construction.java

@@ -1,5 +1,6 @@
 package housing;
 
+import markets.HouseSaleRecord;
 import org.apache.commons.math3.random.MersenneTwister;
 
 import java.io.Serializable;
@@ -41,6 +42,7 @@ public void init() {
 	public void step() {
         // Initialise to zero the number of houses built this month
         nNewBuild = 0;
+
         // First update prices of properties put on the market on previous time steps and still unsold
         for(House h : onMarket) {
             Model.houseSaleMarket.updateOffer(h.getSaleRecord(), h.getSaleRecord().getPrice()*0.95);
@@ -66,7 +68,7 @@ public void step() {
             newHouse = new House((int)(rand.nextDouble()*config.N_QUALITY));
             newHouse.owner = this;
             // ...put the house for sale in the house sale market at the reference price for that quality
-            Model.houseSaleMarket.offer(newHouse,
+            Model.houseSaleMarket.submitOffer(newHouse,
                     Model.housingMarketStats.getReferencePriceForQuality(newHouse.getQuality()));
             // ...add the house to the portfolio of construction sector properties
             onMarket.add(newHouse);

src/main/java/housing/House.java

@@ -1,5 +1,7 @@
 package housing;
 
+import markets.HouseSaleRecord;
+
 import java.io.Serializable;
 
 /**************************************************************************************************
@@ -21,7 +23,7 @@ public class House implements Comparable<House>, Serializable {
     public Household    resident;
     public int          id;
 
-    HouseSaleRecord     saleRecord;
+    HouseSaleRecord saleRecord;
     HouseSaleRecord     rentalRecord;
 
     private int         quality;
@@ -53,6 +55,7 @@ public House(int quality) {
 	HouseSaleRecord getRentalRecord() { return rentalRecord; }
 
 	boolean isOnRentalMarket() { return rentalRecord != null; }
+
     void putForSale(HouseSaleRecord saleRecord) { this.saleRecord = saleRecord; }
 
 	void resetSaleRecord() { saleRecord = null; }

src/main/java/housing/Household.java

@@ -6,6 +6,7 @@
 import java.util.Map.Entry;
 import java.util.TreeMap;
 
+import markets.HouseSaleRecord;
 import org.apache.commons.math3.random.MersenneTwister;
 
 /**************************************************************************************************
@@ -161,7 +162,7 @@ public double getMonthlyGrossTotalIncome() {
     /**
      * Decide what to do with a house h owned by the household:
      * - if the household lives in the house, decide whether to sell it or not
-     * - if the house is up for sale, rethink its offer price, and possibly put it up for rent instead (only BTL investors)
+     * - if the house is up for sale, rethink its submitOffer price, and possibly put it up for rent instead (only BTL investors)
      * - if the house is up for rent, rethink the rent demanded
      *
      * @param house A house owned by the household
@@ -176,14 +177,14 @@ private void manageHouse(House house) {
             if(newPrice > mortgageFor(house).principal) {
                 Model.houseSaleMarket.updateOffer(forSale, newPrice);
             } else {
-                Model.houseSaleMarket.removeOffer(forSale);
+                Model.houseSaleMarket.cancelOffer(forSale);
                 // TODO: First condition is redundant!
                 if(house  != home && house.resident == null) {
-                    Model.houseRentalMarket.offer(house, buyToLetRent(house));
+                    Model.houseRentalMarket.submitOffer(house, buyToLetRent(house));
                 }
             }
         } else if(decideToSellHouse(house)) { // put house on market?
-            if(house.isOnRentalMarket()) Model.houseRentalMarket.removeOffer(house.getRentalRecord());
+            if(house.isOnRentalMarket()) Model.houseRentalMarket.cancelOffer(house.getRentalRecord());
             putHouseForSale(house);
         }
 
@@ -207,7 +208,7 @@ private void putHouseForSale(House h) {
         } else {
             principal = 0.0;
         }
-        Model.houseSaleMarket.offer(h, behaviour.getInitialSalePrice(h.getQuality(), principal));
+        Model.houseSaleMarket.submitOffer(h, behaviour.getInitialSalePrice(h.getQuality(), principal));
     }
 
     /////////////////////////////////////////////////////////
@@ -251,7 +252,7 @@ void completeHousePurchase(HouseSaleRecord sale) {
                 home = sale.house;
                 sale.house.resident = this;
             } else if (sale.house.resident == null) { // put empty buy-to-let house on rental market
-                Model.houseRentalMarket.offer(sale.house, buyToLetRent(sale.house));
+                Model.houseRentalMarket.submitOffer(sale.house, buyToLetRent(sale.house));
             }
             isFirstTimeBuyer = false;
         }
@@ -265,7 +266,7 @@ public void completeHouseSale(HouseSaleRecord sale) {
         bankBalance += sale.getPrice();
         bankBalance -= mortgage.payoff(bankBalance);
         if(sale.house.isOnRentalMarket()) {
-            Model.houseRentalMarket.removeOffer(sale);
+            Model.houseRentalMarket.cancelOffer(sale);
         }
         // TODO: Warning, if bankBalance is not enough to pay mortgage back, then the house stays in housePayments, consequences to be checked!
         if(mortgage.nPayments == 0) {
@@ -299,7 +300,7 @@ public void endOfLettingAgreement(House h, PaymentAgreement contract) {
 //        if(h.resident != null) System.out.println("Strange: renting out a house that has a resident");        
 //        if(h.resident != null && h.resident == h.owner) System.out.println("Strange: renting out a house that belongs to a homeowner");        
         if(h.isOnRentalMarket()) System.out.println("Strange: got endOfLettingAgreement on house on rental market");
-        if(!h.isOnMarket()) Model.houseRentalMarket.offer(h, buyToLetRent(h));
+        if(!h.isOnMarket()) Model.houseRentalMarket.submitOffer(h, buyToLetRent(h));
     }
 
     /**********************************************************
@@ -356,7 +357,7 @@ void completeHouseRental(HouseSaleRecord sale) {
 
 
     /********************************************************
-     * Make the decision whether to bid on the housing market or rental market.
+     * Make the decision whether to submitBid on the housing market or rental market.
      * This is an "intensity of choice" decision (sigma function)
      * on the cost of renting compared to the cost of owning, with
      * COST_OF_RENTING being an intrinsic psychological cost of not
@@ -369,11 +370,11 @@ private void bidForAHome() {
         price = Math.min(price, Model.bank.getMaxMortgage(this, true));
         // Compare costs to decide whether to buy or rent...
         if(behaviour.decideRentOrPurchase(this, price)) {
-            // ... if buying, bid in the house sale market for the capped desired price
-            Model.houseSaleMarket.bid(this, price);
+            // ... if buying, submitBid in the house sale market for the capped desired price
+            Model.houseSaleMarket.submitBid(this, price);
         } else {
-            // ... if renting, bid in the house rental market for the desired rent price
-            Model.houseRentalMarket.bid(this, behaviour.desiredRent(this, monthlyGrossEmploymentIncome));
+            // ... if renting, submitBid in the house rental market for the desired rent price
+            Model.houseRentalMarket.submitBid(this, behaviour.desiredRent(this, monthlyGrossEmploymentIncome));
         }
     }
 
@@ -398,7 +399,7 @@ private boolean decideToSellHouse(House h) {
     @Override
     public void completeHouseLet(HouseSaleRecord sale) {
         if(sale.house.isOnMarket()) {
-            Model.houseSaleMarket.removeOffer(sale.house.getSaleRecord());
+            Model.houseSaleMarket.cancelOffer(sale.house.getSaleRecord());
         }
         monthlyGrossRentalIncome += sale.getPrice();
     }
@@ -439,8 +440,8 @@ void transferAllWealthTo(Household beneficiary) {
                 isHome = false;
             }
             if(h.owner == this) {
-                if(h.isOnRentalMarket()) Model.houseRentalMarket.removeOffer(h.getRentalRecord());
-                if(h.isOnMarket()) Model.houseSaleMarket.removeOffer(h.getSaleRecord());
+                if(h.isOnRentalMarket()) Model.houseRentalMarket.cancelOffer(h.getRentalRecord());
+                if(h.isOnMarket()) Model.houseSaleMarket.cancelOffer(h.getSaleRecord());
                 if(h.resident != null) h.resident.getEvicted();
                 beneficiary.inheritHouse(h, isHome);
             } else {
@@ -485,7 +486,7 @@ private void inheritHouse(House h, boolean wasHome) {
             if(decideToSellHouse(h)) {
                 putHouseForSale(h);
             } else if(h.resident == null) {
-                Model.houseRentalMarket.offer(h, buyToLetRent(h));
+                Model.houseRentalMarket.submitOffer(h, buyToLetRent(h));
             }
         } else {
             // I'm an owner-occupier

src/main/java/housing/HouseholdBehaviour.java

@@ -2,6 +2,7 @@
 
 import java.io.Serializable;
 
+import markets.HouseSaleRecord;
 import org.apache.commons.math3.distribution.LogNormalDistribution;
 import org.apache.commons.math3.random.MersenneTwister;
 
@@ -96,7 +97,7 @@ public class HouseholdBehaviour implements Serializable {
     //----- Owner-Occupier behaviour -----//
 
 	/**
-     * Desired purchase price used to decide whether to buy a house and how much to bid for it
+     * Desired purchase price used to decide whether to buy a house and how much to submitBid for it
      *
 	 * @param monthlyIncome Monthly income of the household
 	 */
@@ -223,7 +224,7 @@ public boolean decideRentOrPurchase(Household me, double desiredPurchasePrice) {
     }
 
 	/********************************************************
-	 * Decide how much to bid on the rental market
+	 * Decide how much to submitBid on the rental market
 	 * Source: Zoopla rental prices 2008-2009 (at Bank of England)
 	 ********************************************************/
 	double desiredRent(Household me, double monthlyIncome) {

src/main/java/housing/IHouseOwner.java

@@ -1,5 +1,7 @@
 package housing;
 
+import markets.HouseSaleRecord;
+
 /***************************************************
  * Common interface for agents who enter the sale
  * market as sellers and, thus, house owners. This

src/main/java/housing/Model.java

@@ -8,6 +8,8 @@
 
 import collectors.*;
 
+import markets.HouseRentalMarket;
+import markets.HouseSaleMarket;
 import org.apache.commons.math3.random.MersenneTwister;
 import org.apache.commons.cli.*;
 import org.apache.commons.io.FileUtils;
@@ -129,7 +131,7 @@ public static void main(String[] args) {
             // For each simulation, run config.N_STEPS time steps
 			for (t = 0; t <= config.N_STEPS; t += 1) {
 
-                // Steps model and stores sale and rental markets bid and offer prices, and their averages, into their
+                // Steps model and stores sale and rental markets submitBid and submitOffer prices, and their averages, into their
                 // respective variables
                 modelStep();
 
@@ -183,13 +185,13 @@ private static void modelStep() {
         construction.step();
         // Updates regional households consumption, housing decisions, and corresponding regional bids and offers
 		for(Household h : households) h.step();
-        // Stores sale market bid and offer prices and averages before bids are matched by clearing the market
+        // Stores sale market submitBid and submitOffer prices and averages before bids are matched by clearing the market
         housingMarketStats.preClearingRecord();
         // Clears sale market and updates the HPI
         houseSaleMarket.clearMarket();
         // Computes and stores several housing market statistics after bids are matched by clearing the market (such as HPI, HPA)
         housingMarketStats.postClearingRecord();
-        // Stores rental market bid and offer prices and averages before bids are matched by clearing the market
+        // Stores rental market submitBid and submitOffer prices and averages before bids are matched by clearing the market
         rentalMarketStats.preClearingRecord();
         // Clears rental market
         houseRentalMarket.clearMarket();

src/main/java/markets/AltHousingMarket.java

@@ -0,0 +1,68 @@
+package markets;
+
+
+import org.apache.commons.math3.random.MersenneTwister;
+
+import java.util.*;
+
+public class AltHousingMarket {
+
+    private MersenneTwister prng;
+    private List<HouseBuyerRecord> buyerRecords;
+    private HashSet<HouseSaleRecord> sellerRecords;
+    private HashMap<HouseSaleRecord, List<HouseBuyerRecord>> potentialMatchedRecords;
+
+    AltHousingMarket(MersenneTwister prng) {
+        this.prng = prng;
+        buyerRecords = new ArrayList<>();
+        sellerRecords = new HashSet<>();
+        potentialMatchedRecords = new HashMap<>();
+    }
+
+    public void submitBid(Bid bid) {
+        HouseBuyerRecord record = HouseBuyerRecord.from(bid);
+        buyerRecords.add(record);
+    }
+
+    public void submitOffer(Offer offer) {
+        HouseSaleRecord record = HouseSaleRecord.from(offer);
+        sellerRecords.add(record);
+    }
+
+    private void findPotentialMatches() {
+        for (HouseBuyerRecord buyerRecord : buyerRecords) {
+            HashSet<HouseSaleRecord> affordableListings = new HashSet<>();
+            for (HouseSaleRecord sellerRecord : sellerRecords) {
+                if (sellerRecord.getPrice() <= buyerRecord.getPrice()) {
+                    affordableListings.add(sellerRecord);
+                }
+            }
+            HouseSaleRecord highestQualityAffordableListing = Collections.max(affordableListings, ???);
+            HashSet<HouseBuyerRecord> existingMatchedRecords = potentialMatchedRecords.getOrDefault(highestQualityAffordableListing, new HashSet<>());
+            existingMatchedRecords.add(buyerRecord);
+        }
+    }
+
+    private HashMap<HouseBuyerRecord, HouseSaleRecord> finalizePotentialMatches() {
+        HashMap<HouseBuyerRecord, HouseSaleRecord> finalizedMatchedRecords = new HashMap<>();
+        for (HouseSaleRecord sellerRecord : sellerRecords) {
+            List<HouseBuyerRecord> potentialBuyers = potentialMatchedRecords.getOrDefault(sellerRecord, new ArrayList<>());
+            if (potentialBuyers.isEmpty()) {
+                sellerRecords.remove(sellerRecord);  // TODO is this the correct behavior if seller has no potential buyers?
+            } else if (potentialBuyers.size() == 1) {
+                HouseBuyerRecord matchedBuyerRecord = potentialBuyers.remove(0);
+                finalizedMatchedRecords.put(matchedBuyerRecord, sellerRecord);
+                buyerRecords.remove(matchedBuyerRecord);
+                sellerRecords.remove(sellerRecord);
+            } else {
+                int idx = prng.nextInt(potentialBuyers.size());
+                HouseBuyerRecord matchedBuyerRecord = potentialBuyers.remove(idx);
+                finalizedMatchedRecords.put(matchedBuyerRecord, sellerRecord);
+                buyerRecords.remove(matchedBuyerRecord);
+                sellerRecords.remove(sellerRecord);
+            }
+        }
+        return finalizedMatchedRecords;
+    }
+
+}

src/main/java/housing/BTLBuyerRecord.java → src/main/java/markets/BTLBuyerRecord.java

@@ -1,4 +1,7 @@
-package housing;
+package markets;
+
+import housing.Household;
+import markets.HouseBuyerRecord;
 
 public class BTLBuyerRecord extends HouseBuyerRecord {
 	private static final long serialVersionUID = 5314886568148212605L;