Change initialization of JinjavaInterpreter to instantiation

src/main/java/com/hubspot/jinjava/Jinjava.java

@@ -194,7 +194,7 @@ public RenderResult renderForResult(String template, Map<String, ?> bindings, Ji
       renderConfig = parentInterpreter.getConfig();
     }
 
-    JinjavaInterpreter interpreter = new JinjavaInterpreter(this, context, renderConfig);
+    JinjavaInterpreter interpreter = globalConfig.getInterpreterFactory().newInstance(this, context, renderConfig);
     JinjavaInterpreter.pushCurrent(interpreter);
 
     try {
@@ -224,7 +224,7 @@ public RenderResult renderForResult(String template, Map<String, ?> bindings, Ji
    * @return a new interpreter instance
    */
   public JinjavaInterpreter newInterpreter() {
-    return new JinjavaInterpreter(this, this.getGlobalContext(), this.getGlobalConfig());
+    return globalConfig.getInterpreterFactory().newInstance(this, this.getGlobalContext(), this.getGlobalConfig());
   }
 
 }

src/main/java/com/hubspot/jinjava/JinjavaConfig.java

@@ -26,6 +26,8 @@
 
 import com.hubspot.jinjava.interpret.Context;
 import com.hubspot.jinjava.interpret.Context.Library;
+import com.hubspot.jinjava.interpret.InterpreterFactory;
+import com.hubspot.jinjava.interpret.JinjavaInterpreterFactory;
 import com.hubspot.jinjava.random.RandomNumberGeneratorStrategy;
 
 public class JinjavaConfig {
@@ -49,17 +51,22 @@ public class JinjavaConfig {
   private final RandomNumberGeneratorStrategy randomNumberGenerator;
   private final boolean validationMode;
   private final long maxStringLength;
+  private InterpreterFactory interpreterFactory;
 
   public static Builder newBuilder() {
     return new Builder();
   }
 
   public JinjavaConfig() {
-    this(StandardCharsets.UTF_8, Locale.ENGLISH, ZoneOffset.UTC, 10, new HashMap<>(), false, false, true, false, 0, false, 0, true, RandomNumberGeneratorStrategy.THREAD_LOCAL, false, 0);
+    this(new JinjavaInterpreterFactory());
+  }
+
+  public JinjavaConfig(InterpreterFactory interpreterFactory) {
+    this(StandardCharsets.UTF_8, Locale.ENGLISH, ZoneOffset.UTC, 10, new HashMap<>(), false, false, true, false, 0, false, 0, true, RandomNumberGeneratorStrategy.THREAD_LOCAL, false, 0, interpreterFactory);
   }
 
   public JinjavaConfig(Charset charset, Locale locale, ZoneId timeZone, int maxRenderDepth) {
-    this(charset, locale, timeZone, maxRenderDepth, new HashMap<>(), false, false, true, false, 0, false, 0, true, RandomNumberGeneratorStrategy.THREAD_LOCAL, false, 0);
+    this(charset, locale, timeZone, maxRenderDepth, new HashMap<>(), false, false, true, false, 0, false, 0, true, RandomNumberGeneratorStrategy.THREAD_LOCAL, false, 0, new JinjavaInterpreterFactory());
   }
 
   private JinjavaConfig(Charset charset,
@@ -77,7 +84,8 @@ private JinjavaConfig(Charset charset,
                         boolean nestedInterpretationEnabled,
                         RandomNumberGeneratorStrategy randomNumberGenerator,
                         boolean validationMode,
-                        long maxStringLength) {
+                        long maxStringLength,
+                        InterpreterFactory interpreterFactory) {
     this.charset = charset;
     this.locale = locale;
     this.timeZone = timeZone;
@@ -94,6 +102,7 @@ private JinjavaConfig(Charset charset,
     this.randomNumberGenerator = randomNumberGenerator;
     this.validationMode = validationMode;
     this.maxStringLength = maxStringLength;
+    this.interpreterFactory = interpreterFactory;
   }
 
   public Charset getCharset() {
@@ -160,6 +169,10 @@ public long getMaxStringLength() {
     return maxStringLength;
   }
 
+  public InterpreterFactory getInterpreterFactory() {
+    return interpreterFactory;
+  }
+
   public static class Builder {
     private Charset charset = StandardCharsets.UTF_8;
     private Locale locale = Locale.ENGLISH;
@@ -179,6 +192,7 @@ public static class Builder {
     private RandomNumberGeneratorStrategy randomNumberGeneratorStrategy = RandomNumberGeneratorStrategy.THREAD_LOCAL;
     private boolean validationMode = false;
     private long maxStringLength = 0;
+    private InterpreterFactory interpreterFactory = new JinjavaInterpreterFactory();
 
     private Builder() {}
 
@@ -263,6 +277,11 @@ public Builder withMaxStringLength(long maxStringLength) {
       return this;
     }
 
+    public Builder withInterperterFactory(InterpreterFactory interperterFactory) {
+      this.interpreterFactory = interperterFactory;
+      return this;
+    }
+
     public JinjavaConfig build() {
       return new JinjavaConfig(charset,
           locale,
@@ -279,7 +298,8 @@ public JinjavaConfig build() {
           nestedInterpretationEnabled,
           randomNumberGeneratorStrategy,
           validationMode,
-          maxStringLength);
+          maxStringLength,
+          interpreterFactory);
     }
 
   }

src/main/java/com/hubspot/jinjava/interpret/InterpreterFactory.java

@@ -0,0 +1,9 @@
+package com.hubspot.jinjava.interpret;
+
+import com.hubspot.jinjava.Jinjava;
+import com.hubspot.jinjava.JinjavaConfig;
+
+public interface InterpreterFactory {
+    JinjavaInterpreter newInstance(JinjavaInterpreter orig);
+    JinjavaInterpreter newInstance(Jinjava application, Context context, JinjavaConfig renderConfig);
+}

src/main/java/com/hubspot/jinjava/interpret/JinjavaInterpreterFactory.java

@@ -0,0 +1,17 @@
+package com.hubspot.jinjava.interpret;
+
+import com.hubspot.jinjava.Jinjava;
+import com.hubspot.jinjava.JinjavaConfig;
+
+public class JinjavaInterpreterFactory implements InterpreterFactory {
+    @Override
+    public JinjavaInterpreter newInstance(JinjavaInterpreter orig) {
+        return new JinjavaInterpreter(orig);
+    }
+
+    @Override
+    public JinjavaInterpreter newInstance(Jinjava application, Context context, JinjavaConfig renderConfig) {
+        return new JinjavaInterpreter(application, context, renderConfig);
+    }
+}
+

src/main/java/com/hubspot/jinjava/lib/tag/FromTag.java

@@ -96,7 +96,7 @@ public String interpret(TagNode tagNode, JinjavaInterpreter interpreter) {
         String template = interpreter.getResource(templateFile);
         Node node = interpreter.parse(template);
 
-        JinjavaInterpreter child = new JinjavaInterpreter(interpreter);
+        JinjavaInterpreter child = interpreter.getConfig().getInterpreterFactory().newInstance(interpreter);
         child.getContext().put(Context.IMPORT_RESOURCE_PATH_KEY, templateFile);
         JinjavaInterpreter.pushCurrent(child);
         try {

src/main/java/com/hubspot/jinjava/lib/tag/ImportTag.java

@@ -97,7 +97,7 @@ public String interpret(TagNode tagNode, JinjavaInterpreter interpreter) {
       String template = interpreter.getResource(templateFile);
       Node node = interpreter.parse(template);
 
-      JinjavaInterpreter child = new JinjavaInterpreter(interpreter);
+      JinjavaInterpreter child = interpreter.getConfig().getInterpreterFactory().newInstance(interpreter);
       child.getContext().put(Context.IMPORT_RESOURCE_PATH_KEY, templateFile);
       JinjavaInterpreter.pushCurrent(child);