Simplify config

pom.xml

@@ -24,6 +24,11 @@
             <artifactId>mason</artifactId>
             <version>19</version>
         </dependency>
+        <dependency>
+            <groupId>com.typesafe</groupId>
+            <artifactId>config</artifactId>
+            <version>1.3.1</version>
+        </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-math3</artifactId>

src/main/java/collectors/CreditSupply.java

@@ -8,31 +8,30 @@
 import org.apache.commons.math3.stat.descriptive.DescriptiveStatistics;
 
 public class CreditSupply extends CollectorBase {
-	private static final long serialVersionUID = 1630707025974306844L;
-
-	private Config config = Model.config;	// Passes the Model's configuration parameters object to a private field
-
-	public CreditSupply() {
-		mortgageCounter = 0;
-		ftbCounter = 0;
-		btlCounter = 0;
-		// TODO: This limit in the number of events taken into account to build statistics is not explained in the paper (affects oo_lti, oo_ltv, btl_ltv, btl_icr, downpayments)
-		setArchiveLength(10000);
-	}
+    private static final long serialVersionUID = 1630707025974306844L;
+
+
+    public CreditSupply() {
+        mortgageCounter = 0;
+        ftbCounter = 0;
+        btlCounter = 0;
+        // TODO: This limit in the number of events taken into account to build statistics is not explained in the paper (affects oo_lti, oo_ltv, btl_ltv, btl_icr, downpayments)
+        setArchiveLength(10000);
+    }
 
-	/***
-	 * collect information for this timestep
-	 */
-	public void step() {
+    /***
+     * collect information for this timestep
+     */
+    public void step() {
         double oldTotalCredit = totalOOCredit + totalBTLCredit;
         totalOOCredit = 0.0;
         totalBTLCredit = 0.0;
         for(MortgageAgreement m : Model.bank.mortgages) {
-        	if(m.isBuyToLet) {
-            	totalBTLCredit += m.principal;
-        	} else {
-        		totalOOCredit += m.principal;
-        	}
+            if(m.isBuyToLet) {
+                totalBTLCredit += m.principal;
+            } else {
+                totalOOCredit += m.principal;
+            }
         }
         netCreditGrowth = (totalOOCredit + totalBTLCredit - oldTotalCredit)/oldTotalCredit;
         nApprovedMortgages = mortgageCounter;
@@ -41,55 +40,55 @@ public void step() {
         mortgageCounter = 0;
         ftbCounter = 0;
         btlCounter = 0;
-	}
+    }
 
-	/***
-	 * record information for a newly issued mortgage
-	 * @param h
-	 * @param approval
-	 */
-	public void recordLoan(Household h, MortgageAgreement approval, House house) {
-		double housePrice;
-		if(config.isMortgageDiagnosticsActive()) {
-			housePrice = approval.principal + approval.downPayment;
-			affordability = config.derivedParams.getAffordabilityDecay()*affordability + (1.0-config.derivedParams.getAffordabilityDecay())*approval.monthlyPayment/(h.monthlyEmploymentIncome);
-			if(approval.principal > 1.0) {
-				if(approval.isBuyToLet) {
-					btl_ltv.addValue(100.0*approval.principal/housePrice);
-//					double icr = Model.rentalMarket.getAverageSalePrice(house.getQuality())*12.0/(approval.principal*Model.bank.getBtLStressedMortgageInterestRate());
-					double icr = Model.rentalMarket.averageSoldGrossYield*approval.purchasePrice/(approval.principal*config.getCentralBankBTLStressedInterest());
-					btl_icr.addValue(icr);
-				} else {
-					oo_ltv.addValue(100.0*approval.principal/housePrice);
-					oo_lti.addValue(approval.principal/h.annualEmploymentIncome());
-				}
-				downpayments.addValue(approval.downPayment);
-			}
-//			approved_mortgages[0][approved_mortgages_index] = approval.principal/(h.annualEmploymentIncome());
-//			approved_mortgages[1][approved_mortgages_index] = approval.downPayment/(h.annualEmploymentIncome());
-//			approved_mortgages_index += 1;
-//			if(approved_mortgages_index == ARCHIVE_LEN) approved_mortgages_index = 0;
-			mortgageCounter += 1;
-			if(approval.isFirstTimeBuyer) ftbCounter += 1;
-			if(approval.isBuyToLet) btlCounter += 1;
-		}
-	}
-	
+    /***
+     * record information for a newly issued mortgage
+     * @param h
+     * @param approval
+     */
+    public void recordLoan(Household h, MortgageAgreement approval, House house) {
+        double housePrice;
+        if(config.isMortgageDiagnosticsActive()) {
+            housePrice = approval.principal + approval.downPayment;
+            affordability = config.derivedParams.getAffordabilityDecay()*affordability + (1.0-config.derivedParams.getAffordabilityDecay())*approval.monthlyPayment/(h.monthlyEmploymentIncome);
+            if(approval.principal > 1.0) {
+                if(approval.isBuyToLet) {
+                    btl_ltv.addValue(100.0*approval.principal/housePrice);
+//                    double icr = Model.rentalMarket.getAverageSalePrice(house.getQuality())*12.0/(approval.principal*Model.bank.getBtLStressedMortgageInterestRate());
+                    double icr = Model.rentalMarket.averageSoldGrossYield*approval.purchasePrice/(approval.principal*config.getCentralBankBTLStressedInterest());
+                    btl_icr.addValue(icr);
+                } else {
+                    oo_ltv.addValue(100.0*approval.principal/housePrice);
+                    oo_lti.addValue(approval.principal/h.annualEmploymentIncome());
+                }
+                downpayments.addValue(approval.downPayment);
+            }
+//            approved_mortgages[0][approved_mortgages_index] = approval.principal/(h.annualEmploymentIncome());
+//            approved_mortgages[1][approved_mortgages_index] = approval.downPayment/(h.annualEmploymentIncome());
+//            approved_mortgages_index += 1;
+//            if(approved_mortgages_index == ARCHIVE_LEN) approved_mortgages_index = 0;
+            mortgageCounter += 1;
+            if(approval.isFirstTimeBuyer) ftbCounter += 1;
+            if(approval.isBuyToLet) btlCounter += 1;
+        }
+    }
+    
 
-	// ---- Mason stuff
-	// ----------------
-	public String desLTI() {return("Loan to Income constraint on mortgages");}
-	public String desTHETA_FTB() {return("Loan to Value haircut for first time buyers");}
-	public String desTHETA_HOME() {return("Loan to Value haircut for homeowners");}
-	public String desTHETA_BTL() {return("Loan to Value haircut for buy-to-let investors");}
-	public String desN_PAYMENTS() {return("Number of monthly repayments in a mortgage");}
-	public double getBaseRate() {
-		return Model.bank.getBaseRate();
-	}
-	public void setBaseRate(double rate) {
-		Model.bank.setBaseRate(rate);
-	}
-	
+    // ---- Mason stuff
+    // ----------------
+    public String desLTI() {return("Loan to Income constraint on mortgages");}
+    public String desTHETA_FTB() {return("Loan to Value haircut for first time buyers");}
+    public String desTHETA_HOME() {return("Loan to Value haircut for homeowners");}
+    public String desTHETA_BTL() {return("Loan to Value haircut for buy-to-let investors");}
+    public String desN_PAYMENTS() {return("Number of monthly repayments in a mortgage");}
+    public double getBaseRate() {
+        return Model.bank.getBaseRate();
+    }
+    public void setBaseRate(double rate) {
+        Model.bank.setBaseRate(rate);
+    }
+    
     public double [] getOOLTVDistribution() {return(oo_ltv.getValues());}
     public double [] getOOLTIDistribution() {return(oo_lti.getValues());}
     public double [] getBTLLTVDistribution() {return(btl_ltv.getValues());}
@@ -115,53 +114,53 @@ public void setSaveBTLICRDistribution(boolean doSave) throws FileNotFoundExcepti
 
 
     public int getNRegisteredMortgages() {
-    	return(Model.bank.mortgages.size());
+        return(Model.bank.mortgages.size());
     }
 
-	public int getArchiveLength() {
-		return archiveLength;
-	}
-	
-	public void writeDistributionToFile(double [] vals, String filename) throws FileNotFoundException, UnsupportedEncodingException {
+    public int getArchiveLength() {
+        return archiveLength;
+    }
+    
+    public void writeDistributionToFile(double [] vals, String filename) throws FileNotFoundException, UnsupportedEncodingException {
         PrintWriter dist = new PrintWriter(filename, "UTF-8");
         if(vals.length > 0) {
-        	dist.print(vals[0]);
-        	for(int i=1; i<vals.length; ++i) {
-        		dist.print(", "+vals[i]);
-        	}
+            dist.print(vals[0]);
+            for(int i=1; i<vals.length; ++i) {
+                dist.print(", "+vals[i]);
+            }
         }
         dist.close();
-	}
+    }
 
-	public void setArchiveLength(int archiveLength) {
-		this.archiveLength = archiveLength;
-		oo_lti = new DescriptiveStatistics(archiveLength);
-		oo_ltv = new DescriptiveStatistics(archiveLength);
-		btl_ltv = new DescriptiveStatistics(archiveLength);
-		btl_icr = new DescriptiveStatistics(archiveLength);
-		downpayments = new DescriptiveStatistics(archiveLength);
-	}
+    public void setArchiveLength(int archiveLength) {
+        this.archiveLength = archiveLength;
+        oo_lti = new DescriptiveStatistics(archiveLength);
+        oo_ltv = new DescriptiveStatistics(archiveLength);
+        btl_ltv = new DescriptiveStatistics(archiveLength);
+        btl_icr = new DescriptiveStatistics(archiveLength);
+        downpayments = new DescriptiveStatistics(archiveLength);
+    }
 
 
-	//public double STATS_DECAY = 0.98; 	// Decay constant (per step) for exp averaging of stats
-	//public int 	HISTOGRAM_NBINS = 101;
+    //public double STATS_DECAY = 0.98;     // Decay constant (per step) for exp averaging of stats
+    //public int     HISTOGRAM_NBINS = 101;
 
-	public int archiveLength; // number of mortgage approvals to remember
-	public double affordability = 0.0;
-	public DescriptiveStatistics oo_lti;
-	public DescriptiveStatistics oo_ltv;
-	public DescriptiveStatistics btl_ltv;
-	public DescriptiveStatistics btl_icr;
-	public DescriptiveStatistics downpayments;
-//	public double [][] approved_mortgages = new double [2][ARCHIVE_LEN]; // (loan/income, downpayment/income) pairs
-//	public int approved_mortgages_index;
-	public int mortgageCounter;
-	public int ftbCounter;	
-	public int btlCounter;	
-	public int nApprovedMortgages; // total number of new mortgages
-	public int nFTBMortgages; // number of new first time buyer mortgages given
-	public int nBTLMortgages; // number of new buy to let mortages given
-	public double totalBTLCredit = 0.0; // buy to let mortgage credit
-	public double totalOOCredit = 0.0; // owner-occupier mortgage credit	
-	public double netCreditGrowth; // rate of change of credit per month as percentage
+    public int archiveLength; // number of mortgage approvals to remember
+    public double affordability = 0.0;
+    public DescriptiveStatistics oo_lti;
+    public DescriptiveStatistics oo_ltv;
+    public DescriptiveStatistics btl_ltv;
+    public DescriptiveStatistics btl_icr;
+    public DescriptiveStatistics downpayments;
+//    public double [][] approved_mortgages = new double [2][ARCHIVE_LEN]; // (loan/income, downpayment/income) pairs
+//    public int approved_mortgages_index;
+    public int mortgageCounter;
+    public int ftbCounter;    
+    public int btlCounter;    
+    public int nApprovedMortgages; // total number of new mortgages
+    public int nFTBMortgages; // number of new first time buyer mortgages given
+    public int nBTLMortgages; // number of new buy to let mortages given
+    public double totalBTLCredit = 0.0; // buy to let mortgage credit
+    public double totalOOCredit = 0.0; // owner-occupier mortgage credit    
+    public double netCreditGrowth; // rate of change of credit per month as percentage
 }

src/main/java/configuration/BankConfig.java

@@ -0,0 +1,34 @@
+package configuration;
+
+
+import com.typesafe.config.Config;
+
+
+public class BankConfig {
+
+    private int mortgageDurationYears;
+    private double initialBaseRate;
+    private double creditSupplyTarget;
+
+    BankConfig(Config config) {
+        mortgageDurationYears = config.getInt("mortgage-duration-years");
+        initialBaseRate = config.getDouble("initial=base-rate");
+        creditSupplyTarget = config.getDouble("credit-supply-target");
+    }
+
+    /** Mortgage duration in years. */
+    public int getMortgageDurationYears() {
+        return mortgageDurationYears;
+    }
+
+    /** Bank initial base-rate, which remains currently unchanged. */
+    public double getInitialBaseRate() {
+        return initialBaseRate;
+    }
+
+    /** Bank's target supply of credit per household per month. */
+    public double getCreditSupplyTarget() {
+        return creditSupplyTarget;
+    }
+
+}

src/main/java/configuration/BuyToLetConfig.java

@@ -0,0 +1,60 @@
+package configuration;
+
+import com.typesafe.config.Config;
+
+/** Class encapsulating the parameters for "buy-to-let" investors.
+ *
+ * @author davidrpugh
+ */
+public class BuyToLetConfig {
+
+    private double probabilityInvestor;
+    private double minIncomePercentile;
+    private double fundamentalistCapitalGainCoefficient;
+    private double trendFollowersCapitalGainCoefficient;
+    private double probabilityFundamentalist;
+    private boolean buyToLetYieldScaling;
+
+    BuyToLetConfig(Config config) {
+        probabilityInvestor = config.getDouble("probability-investor");
+        minIncomePercentile = config.getDouble("min-income-percentile");
+        fundamentalistCapitalGainCoefficient = config.getDouble("fundamentalist-capitalGain-coefficient");
+        trendFollowersCapitalGainCoefficient = config.getDouble("trend-followers-capital-gain-coefficient");
+        probabilityFundamentalist = config.getDouble("probability-fundamentalist");
+        buyToLetYieldScaling = config.getBoolean("buy-to-let-yield-scaling");
+    }
+
+    /** Prior probability of being (wanting to be) a BTL investor (double)
+     *
+     * TODO: 6/22/2017 Shouldn't this be 4% according to the article?
+     */
+    public double getProbabilityInvestor() {
+        return probabilityInvestor;
+    }
+
+    /** Minimum income percentile for a household to be a BTL investor. */
+    public double getMinIncomePercentile() {
+        return minIncomePercentile;
+    }
+
+    /** Weight that fundamentalists put on cap gain. */
+    public double getFundamentalistCapitalGainCoefficient() {
+        return fundamentalistCapitalGainCoefficient;
+    }
+
+    /** Weight that trend-followers put on cap gain. */
+    public double getTrendFollowersCapitalGainCoefficient() {
+        return trendFollowersCapitalGainCoefficient;
+    }
+
+    /** Probability that a BTL investor is a fundamentalist versus a trend-follower. */
+    public double getProbabilityFundamentalist() {
+        return probabilityFundamentalist;
+    }
+
+    /** Chooses between two possible equations for BTL investors to make their buy/sell decisions (boolean) */
+    public boolean isBuyToLetYieldScaling() {
+        return buyToLetYieldScaling;
+    }
+
+}