added loader that works from memory

pebble/src/main/java/io/pebbletemplates/pebble/loader/MemoryLoader.java

@@ -0,0 +1,95 @@
+package io.pebbletemplates.pebble.loader;
+
+import java.io.Reader;
+import java.io.StringReader;
+import java.util.ArrayList;
+import java.util.Hashtable;
+import com.mitchellbosecke.pebble.error.LoaderException;
+
+public class MemoryLoader implements Loader<String> {
+    private String prefix;
+
+    private String suffix;
+
+    private String charset = "UTF-8";
+
+    ArrayList<Hashtable<String, String>> fileTable = new ArrayList<>();
+
+    public Reader getReader(String templateName)
+    {
+        String content = "";
+        for (Hashtable<String, String> hashtable : fileTable)
+        {
+            if(hashtable.containsKey("templateName"))
+            {
+                if(hashtable.get("templateName").equals(templateName))
+                {
+                    content = hashtable.get("content");
+                    break;
+                }
+            }
+        }
+
+        if(content.isEmpty())
+        {
+            throw new LoaderException(null, "Could not find template \"" + templateName + "\""); //XSS?
+        }
+
+        return new StringReader(content);
+    }
+
+    public void addFile(String templateName, String content)
+    {
+        Hashtable<String, String> table = new Hashtable<>();
+        table.put("templateName", templateName);
+        table.put("content", content);
+        fileTable.add(table);
+    }
+
+    public String getSuffix() {
+        return this.suffix;
+    }
+
+    public void setSuffix(String suffix) {
+        this.suffix = suffix;
+    }
+
+    public String getPrefix() {
+        return this.prefix;
+    }
+
+    public void setPrefix(String prefix) {
+        this.prefix = prefix;
+    }
+
+    public String getCharset() {
+        return this.charset;
+    }
+
+    public void setCharset(String charset) {
+        this.charset = charset;
+    }
+
+    public String resolveRelativePath(String relativePath, String anchorPath) {
+        return relativePath; // hierarchy is flat
+    }
+
+    public String createCacheKey(String templateName) {
+        return templateName;
+    }
+
+    public boolean resourceExists(String templateName)
+    {
+        for (Hashtable<String, String> hashtable : fileTable)
+        {
+            if(hashtable.containsKey("templateName"))
+            {
+                if(hashtable.get("templateName").equals(templateName))
+                {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+}

pebble/src/test/java/io/pebbletemplates/pebble/LoaderTest.java

@@ -17,17 +17,14 @@
 import io.pebbletemplates.pebble.loader.StringLoader;
 import io.pebbletemplates.pebble.template.PebbleTemplate;
 
+import org.apache.commons.io.FileUtils;
 import org.junit.jupiter.api.Test;
 
-import java.io.File;
-import java.io.IOException;
-import java.io.Reader;
-import java.io.StringReader;
-import java.io.StringWriter;
-import java.io.Writer;
+import java.io.*;
 import java.net.URISyntaxException;
 import java.net.URL;
 import java.net.URLClassLoader;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -108,6 +105,22 @@ void testDelegatingLoader() throws PebbleException, IOException {
     assertEquals("LOADER ONE", writer.toString());
   }
 
+  @Test
+  void testMemoryLoader() throws PebbleException, IOException, URISyntaxException {
+    MemoryLoader loader = new MemoryLoader();
+    loader.setSuffix(".suffix");
+    PebbleEngine engine = new PebbleEngine.Builder().loader(loader).strictVariables(false).build();
+    URL url = this.getClass().getResource("/templates/template.loaderTest.peb");
+    String content = FileUtils.readFileToString(new File(url.toURI()), StandardCharsets.UTF_8);
+
+    loader.addFile("main", content);
+    PebbleTemplate template1 = engine.getTemplate("main");
+    Writer writer1 = new StringWriter();
+    template1.evaluate(writer1);
+    assertEquals("SUCCESS", writer1.toString());
+
+  }
+
   @Test
   void testGetLiteralTemplate() throws IOException {
     PebbleEngine engine = new PebbleEngine.Builder().build();