Only allow a single interpreter to be built

Renamed Environment to RuntimeEnvironment

src/environment/RuntimeEnvironment.java

@@ -2,11 +2,11 @@ package environment;
 
 import java.io.*;
 
-public class Environment {
+public class RuntimeEnvironment {
 
-    private static Environment uniqueInstance = new Environment();
+    private static RuntimeEnvironment uniqueInstance = new RuntimeEnvironment();
 
-    public static Environment getInstance() {
+    public static RuntimeEnvironment getInstance() {
         return uniqueInstance;
     }
 
@@ -16,7 +16,7 @@ public class Environment {
     private Runnable terminationFunction;
     private Runnable errorTerminationFunction;
 
-    private Environment() {}
+    private RuntimeEnvironment() {}
 
     public void setInput(InputStream input) {
         this.input = input;

src/error/ErrorManager.java

@@ -2,7 +2,7 @@ package error;
 
 import java.text.MessageFormat;
 
-import environment.Environment;
+import environment.RuntimeEnvironment;
 
 /**
  * Prints error messages and potentially terminates the application.
@@ -15,10 +15,10 @@ public class ErrorManager {
     private static final String ANSI_RED = "\u001B[31m";
     private static final String ANSI_PURPLE = "\u001B[35m";
 
-    private Environment environment;
+    private RuntimeEnvironment environment;
 
     public ErrorManager() {
-        this.environment = Environment.getInstance();
+        this.environment = RuntimeEnvironment.getInstance();
     }
 
     public void generateError(LispException lispException) {

src/function/builtin/EXIT.java

@@ -1,18 +1,18 @@
 package function.builtin;
 
-import environment.Environment;
+import environment.RuntimeEnvironment;
 import function.*;
 import sexpression.*;
 
 public class EXIT extends LispFunction {
 
     private ArgumentValidator argumentValidator;
-    private Environment environment;
+    private RuntimeEnvironment environment;
 
     public EXIT() {
         this.argumentValidator = new ArgumentValidator("EXIT");
         this.argumentValidator.setMaximumNumberOfArguments(0);
-        this.environment = Environment.getInstance();
+        this.environment = RuntimeEnvironment.getInstance();
     }
 
     public SExpression call(Cons argumentList) {

src/function/builtin/LOAD.java

@@ -3,7 +3,7 @@ package function.builtin;
 import java.io.*;
 import java.text.MessageFormat;
 
-import environment.Environment;
+import environment.RuntimeEnvironment;
 import function.*;
 import parser.LispParser;
 import sexpression.*;
@@ -11,13 +11,13 @@ import sexpression.*;
 public class LOAD extends LispFunction {
 
     private ArgumentValidator argumentValidator;
-    private Environment environment;
+    private RuntimeEnvironment environment;
 
     public LOAD() {
         this.argumentValidator = new ArgumentValidator("LOAD");
         this.argumentValidator.setExactNumberOfArguments(1);
         this.argumentValidator.setEveryArgumentExpectedType(LispString.class);
-        this.environment = Environment.getInstance();
+        this.environment = RuntimeEnvironment.getInstance();
     }
 
     public SExpression call(Cons argumentList) {

src/function/builtin/PRINT.java

@@ -1,18 +1,18 @@
 package function.builtin;
 
-import environment.Environment;
+import environment.RuntimeEnvironment;
 import function.*;
 import sexpression.*;
 
 public class PRINT extends LispFunction {
 
     private ArgumentValidator argumentValidator;
-    private Environment environment;
+    private RuntimeEnvironment environment;
 
     public PRINT() {
         this.argumentValidator = new ArgumentValidator("PRINT");
         this.argumentValidator.setExactNumberOfArguments(1);
-        this.environment = Environment.getInstance();
+        this.environment = RuntimeEnvironment.getInstance();
     }
 
     public SExpression call(Cons argumentList) {

src/function/builtin/special/DEFUN.java

@@ -2,7 +2,7 @@ package function.builtin.special;
 
 import java.text.MessageFormat;
 
-import environment.Environment;
+import environment.RuntimeEnvironment;
 import function.*;
 import function.builtin.cons.LIST;
 import sexpression.*;
@@ -13,7 +13,7 @@ public class DEFUN extends LispFunction {
     private ArgumentValidator argumentValidator;
     private ArgumentValidator lambdaListIsListValidator;
     private ArgumentValidator lambdaListValidator;
-    private Environment environment;
+    private RuntimeEnvironment environment;
 
     public DEFUN() {
         this.argumentValidator = new ArgumentValidator("DEFUN");
@@ -26,7 +26,7 @@ public class DEFUN extends LispFunction {
         this.lambdaListValidator = new ArgumentValidator("DEFUN|parameter|");
         this.lambdaListValidator.setEveryArgumentExpectedType(Symbol.class);
 
-        this.environment = Environment.getInstance();
+        this.environment = RuntimeEnvironment.getInstance();
     }
 
     public SExpression call(Cons argumentList) {

src/interpreter/LispInterpreter.java

@@ -3,7 +3,7 @@ package interpreter;
 import java.io.*;
 import java.text.MessageFormat;
 
-import environment.Environment;
+import environment.RuntimeEnvironment;
 import error.*;
 import function.builtin.EVAL;
 import parser.LispParser;
@@ -16,16 +16,16 @@ public class LispInterpreter {
 
     private LispParser parser;
     private ErrorManager errorManager;
-    protected Environment environment;
+    protected RuntimeEnvironment environment;
 
     public LispInterpreter() {
-        this.environment = Environment.getInstance();
+        this.environment = RuntimeEnvironment.getInstance();
         this.errorManager = new ErrorManager();
         this.parser = new LispParser(this.environment.getInput(), this.environment.getInputName());
     }
 
     public LispInterpreter(String fileName) {
-        this.environment = Environment.getInstance();
+        this.environment = RuntimeEnvironment.getInstance();
         this.errorManager = new ErrorManager();
 
         try {

src/interpreter/LispInterpreterBuilderImpl.java

@@ -2,47 +2,60 @@ package interpreter;
 
 import java.io.*;
 
-import environment.Environment;
+import environment.RuntimeEnvironment;
+import error.*;
 
 public class LispInterpreterBuilderImpl implements LispInterpreterBuilder {
     
-    private Environment environment;
+    private static LispInterpreterBuilder uniqueInstance = new LispInterpreterBuilderImpl();
+    
+    public static LispInterpreterBuilder getInstance() {
+        return uniqueInstance;
+    }
+
+    private InputStream inputStream;
+    private PrintStream outputStream;
+    private PrintStream errorOutputStream;
+    private Runnable terminationFunction;
+    private Runnable errorTerminationFunction;
+    private RuntimeEnvironment environment;
     private String fileName;
     private boolean isInteractive;
+    private boolean isBuilt;
 
-    public LispInterpreterBuilderImpl() {
-        this.environment = Environment.getInstance();
+    private LispInterpreterBuilderImpl() {
+        this.environment = RuntimeEnvironment.getInstance();
         this.fileName = "";
         this.isInteractive = true;
+        this.isBuilt = false;
     }
 
     @Override
     public void setInput(InputStream inputStream) {
-        this.environment.setInput(inputStream);
+        this.inputStream = inputStream;
     }
 
     @Override
     public void setOutput(PrintStream outputStream) {
-        this.environment.setOutput(outputStream);
+        this.outputStream = outputStream;
 
     }
 
     @Override
     public void setErrorOutput(PrintStream errorOutputStream) {
-        this.environment.setErrorOutput(errorOutputStream);
+        this.errorOutputStream = errorOutputStream;
     }
 
     @Override
     public void setTerminationFunction(Runnable terminationFunction) {
-        this.environment.setTerminationFunction(terminationFunction);
+        this.terminationFunction = terminationFunction;
     }
 
     @Override
     public void setErrorTerminationFunction(Runnable errorTerminationFunction) {
-        this.environment.setErrorTerminationFunction(errorTerminationFunction);
+        this.errorTerminationFunction = errorTerminationFunction;
     }
 
-
     @Override
     public void useFile(String fileName) {
         this.fileName = fileName;
@@ -51,10 +64,40 @@ public class LispInterpreterBuilderImpl implements LispInterpreterBuilder {
 
     @Override
     public LispInterpreter build() {
-        if (isInteractive)
-            return new InteractiveLispInterpreter();
+        if (!isBuilt)
+            return buildInterpreter();
         else
-            return new LispInterpreter(fileName);
+            throw new InterpreterAlreadyBuiltException();
+    }
+
+    private LispInterpreter buildInterpreter() {
+        environment.setInput(inputStream);
+        environment.setOutput(outputStream);
+        environment.setErrorOutput(errorOutputStream);
+        environment.setTerminationFunction(terminationFunction);
+        environment.setErrorTerminationFunction(errorTerminationFunction);
+
+        LispInterpreter lispInterpreter = isInteractive ? new InteractiveLispInterpreter()
+                                                        : new LispInterpreter(fileName);
+
+        isBuilt = true;
+
+        return lispInterpreter;
+    }
+
+    public class InterpreterAlreadyBuiltException extends LispException {
+
+        private static final long serialVersionUID = 1L;
+        
+        @Override
+        public int getSeverity() {
+            return ErrorManager.CRITICAL_LEVEL;
+        }
+
+        @Override
+        public String getMessage() {
+            return "Refusing to build more than one interpreter.";
+        }
     }
 
 }

src/main/LispMain.java

@@ -12,7 +12,7 @@ public class LispMain {
     }
 
     private static LispInterpreter buildInterpreter(String[] args) {
-        LispInterpreterBuilder builder = new LispInterpreterBuilderImpl();
+        LispInterpreterBuilder builder = LispInterpreterBuilderImpl.getInstance();
         builder.setInput(System.in);
         builder.setOutput(System.out);
         builder.setErrorOutput(System.err);

test/error/ErrorManagerTester.java

@@ -7,7 +7,7 @@ import java.util.*;
 
 import org.junit.*;
 
-import environment.Environment;
+import environment.RuntimeEnvironment;
 
 public class ErrorManagerTester {
 
@@ -18,8 +18,8 @@ public class ErrorManagerTester {
     private ByteArrayOutputStream outputStream;
 
     private ErrorManager createErrorManagerWithIndicators() {
-        Environment.getInstance().setErrorTerminationFunction(() -> indicatorSet.add(TERMINATED));
-        Environment.getInstance().setErrorOutput(new PrintStream(outputStream));
+        RuntimeEnvironment.getInstance().setErrorTerminationFunction(() -> indicatorSet.add(TERMINATED));
+        RuntimeEnvironment.getInstance().setErrorOutput(new PrintStream(outputStream));
 
         return new ErrorManager();
     }

test/function/builtin/EXITTester.java

@@ -7,7 +7,7 @@ import java.util.*;
 
 import org.junit.*;
 
-import environment.Environment;
+import environment.RuntimeEnvironment;
 import function.ArgumentValidator.TooManyArgumentsException;
 
 public class EXITTester {
@@ -26,7 +26,7 @@ public class EXITTester {
     @Before
     public void setUp() {
         indicatorSet = new HashSet<>();
-        Environment.getInstance().setTerminationFunction(() -> indicatorSet.add(TERMINATED));
+        RuntimeEnvironment.getInstance().setTerminationFunction(() -> indicatorSet.add(TERMINATED));
     }
 
     @Test

test/function/builtin/LOADTester.java

@@ -7,7 +7,7 @@ import java.io.*;
 
 import org.junit.*;
 
-import environment.Environment;
+import environment.RuntimeEnvironment;
 import function.ArgumentValidator.*;
 import sexpression.*;
 
@@ -26,7 +26,7 @@ public class LOADTester {
     @Before
     public void setUp() {
         this.outputStream = new ByteArrayOutputStream();
-        Environment.getInstance().setErrorOutput(new PrintStream(outputStream));
+        RuntimeEnvironment.getInstance().setErrorOutput(new PrintStream(outputStream));
     }
 
     @Test

test/function/builtin/PRINTTester.java

@@ -8,7 +8,7 @@ import java.text.MessageFormat;
 
 import org.junit.*;
 
-import environment.Environment;
+import environment.RuntimeEnvironment;
 import function.ArgumentValidator.*;
 
 public class PRINTTester {
@@ -22,7 +22,7 @@ public class PRINTTester {
     @Before
     public void setUp() {
         this.outputStream = new ByteArrayOutputStream();
-        Environment.getInstance().setOutput(new PrintStream(outputStream));
+        RuntimeEnvironment.getInstance().setOutput(new PrintStream(outputStream));
     }
 
     @Test

test/function/builtin/special/DEFUNTester.java

@@ -7,7 +7,7 @@ import java.io.*;
 
 import org.junit.*;
 
-import environment.Environment;
+import environment.RuntimeEnvironment;
 import function.ArgumentValidator.*;
 import table.FunctionTable;
 
@@ -22,7 +22,7 @@ public class DEFUNTester {
     @Before
     public void setUp() {
         this.outputStream = new ByteArrayOutputStream();
-        Environment.getInstance().setOutput(new PrintStream(outputStream));
+        RuntimeEnvironment.getInstance().setOutput(new PrintStream(outputStream));
         FunctionTable.reset();
     }