add PromptTemplate

Author: dzlab

llm4j-api/pom.xml

@@ -21,6 +21,15 @@
 
   <properties>
     <module-name>org.llm4j</module-name>
+    <commons-text.version>1.10.0</commons-text.version>
   </properties>
 
+  <dependencies>
+    <dependency>
+      <groupId>org.apache.commons</groupId>
+      <artifactId>commons-text</artifactId>
+      <version>${commons-text.version}</version>
+    </dependency>
+  </dependencies>
+
 </project>

llm4j-api/src/main/java/org/llm4j/api/PromptTemplate.java

@@ -0,0 +1,42 @@
+package org.llm4j.api;
+
+import org.apache.commons.text.StringSubstitutor;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.HashMap;
+import java.util.Map;
+
+public class PromptTemplate {
+    String template = "";
+    Map<String, Object> params = new HashMap<>();
+
+    String prefix = "{";
+    String suffix = "}";
+
+    public PromptTemplate withFile(String fileName) {
+        template = "";
+        try {
+            ClassLoader classloader = getClass().getClassLoader();
+            Path path = Paths.get(classloader.getResource(fileName).toURI());
+            for(String line: Files.readAllLines(path)) {
+                template += "\n" + line;
+            }
+            template = template.substring("\n".length());
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+        return this;
+    }
+
+    public PromptTemplate withParam(String key, Object value) {
+        this.params.put(key, value);
+        return this;
+    }
+
+
+    public String render() {
+        return StringSubstitutor.replace(template, params, prefix, suffix);
+    }
+}