Generate DOT graphs to visualize a Velocity template's AST. To run this program, the following dependencies are needed: velocity-1.6.4.jar/commons-collections-3.2.1.jar/commons-lang-2.5.jar

ASTDotGenerator.java

import static org.apache.commons.lang.StringEscapeUtils.escapeJava;
import static org.apache.commons.lang.StringUtils.isEmpty;

import java.util.HashMap;
import java.util.Map;

import org.apache.velocity.runtime.parser.node.ASTAddNode;
import org.apache.velocity.runtime.parser.node.ASTAndNode;
import org.apache.velocity.runtime.parser.node.ASTAssignment;
import org.apache.velocity.runtime.parser.node.ASTBlock;
import org.apache.velocity.runtime.parser.node.ASTComment;
import org.apache.velocity.runtime.parser.node.ASTDirective;
import org.apache.velocity.runtime.parser.node.ASTDivNode;
import org.apache.velocity.runtime.parser.node.ASTEQNode;
import org.apache.velocity.runtime.parser.node.ASTElseIfStatement;
import org.apache.velocity.runtime.parser.node.ASTElseStatement;
import org.apache.velocity.runtime.parser.node.ASTEscape;
import org.apache.velocity.runtime.parser.node.ASTEscapedDirective;
import org.apache.velocity.runtime.parser.node.ASTExpression;
import org.apache.velocity.runtime.parser.node.ASTFalse;
import org.apache.velocity.runtime.parser.node.ASTFloatingPointLiteral;
import org.apache.velocity.runtime.parser.node.ASTGENode;
import org.apache.velocity.runtime.parser.node.ASTGTNode;
import org.apache.velocity.runtime.parser.node.ASTIdentifier;
import org.apache.velocity.runtime.parser.node.ASTIfStatement;
import org.apache.velocity.runtime.parser.node.ASTIntegerLiteral;
import org.apache.velocity.runtime.parser.node.ASTIntegerRange;
import org.apache.velocity.runtime.parser.node.ASTLENode;
import org.apache.velocity.runtime.parser.node.ASTLTNode;
import org.apache.velocity.runtime.parser.node.ASTMap;
import org.apache.velocity.runtime.parser.node.ASTMethod;
import org.apache.velocity.runtime.parser.node.ASTModNode;
import org.apache.velocity.runtime.parser.node.ASTMulNode;
import org.apache.velocity.runtime.parser.node.ASTNENode;
import org.apache.velocity.runtime.parser.node.ASTNotNode;
import org.apache.velocity.runtime.parser.node.ASTObjectArray;
import org.apache.velocity.runtime.parser.node.ASTOrNode;
import org.apache.velocity.runtime.parser.node.ASTReference;
import org.apache.velocity.runtime.parser.node.ASTSetDirective;
import org.apache.velocity.runtime.parser.node.ASTStop;
import org.apache.velocity.runtime.parser.node.ASTStringLiteral;
import org.apache.velocity.runtime.parser.node.ASTSubtractNode;
import org.apache.velocity.runtime.parser.node.ASTText;
import org.apache.velocity.runtime.parser.node.ASTTrue;
import org.apache.velocity.runtime.parser.node.ASTWord;
import org.apache.velocity.runtime.parser.node.ASTprocess;
import org.apache.velocity.runtime.parser.node.NodeUtils;
import org.apache.velocity.runtime.parser.node.ParserVisitor;
import org.apache.velocity.runtime.parser.node.SimpleNode;

/**
 * Generate DOT graphs to visualize a Velocity template's AST.
 * This class is not thread-safe. DO NOT use share between threads.
 * 
 * @author RednaxelaFX
 * 
 */
public class ASTDotGenerator implements ParserVisitor {
	private StringBuilder output;
	private Map<SimpleNode, String> nodeNames;
	private int nodeCount;

	public String generateDot(SimpleNode node) {
		init();

		output = new StringBuilder();
		output.append("digraph {\n  node [fontsize=12, font=Courier, shape=ellipse]");
		
		// recursively traverse the AST
		node.jjtAccept(this, null);
		
		output.append("}");
		return output.toString();
	}

	private void init() {
		nodeNames = new HashMap<SimpleNode, String>();
		nodeCount = 0;
	}

	private void showNodeCommon(SimpleNode node) {
		// show parent-child relationship
		SimpleNode parent = (SimpleNode) node.jjtGetParent();
		if (parent != null) {
			showRelationship(parent, node);
		}

		// show children
		node.childrenAccept(this, null);
	}

	private String getName(SimpleNode node) {
		String cachedName = nodeNames.get(node);
		if (cachedName != null)
			return cachedName;

		String newName = "node_" + nodeCount++;
		nodeNames.put(node, newName);
		return newName;
	}

	private void declareNode(SimpleNode node, String details) {
		output
			.append("  ")
			.append(getName(node))
			.append(" [label=\"")
			.append(node.getClass().getSimpleName());
		if (isEmpty(details)) {
			output.append("\"]\n");
		} else {
			output.append("\\n[").append(escapeJava(details)).append("]\"]\n");
		}
	}

	private void showRelationship(SimpleNode parent, SimpleNode child) {
		output
			.append("  ")
			.append(getName(parent))
			.append(" -> ")
			.append(getName(child))
			.append("\n");
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.SimpleNode, java.lang.Object)
	 */
	@Override
	public Object visit(SimpleNode node, Object data) {
		// NOTE: ParserVisitor interface is missing a visit(ASTMathNode) method,
		//       so calling ASTMathNode.visit(ParserVisitor, Object) will end up
		//       calling this overload.
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTprocess, java.lang.Object)
	 */
	@Override
	public Object visit(ASTprocess node, Object data) {
		declareNode(node, "templateName=" + node.getTemplateName());
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTEscapedDirective, java.lang.Object)
	 */
	@Override
	public Object visit(ASTEscapedDirective node, Object data) {
		declareNode(node, node.literal());
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTEscape, java.lang.Object)
	 */
	@Override
	public Object visit(ASTEscape node, Object data) {
		declareNode(node, node.val);
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTComment, java.lang.Object)
	 */
	@Override
	public Object visit(ASTComment node, Object data) {
		declareNode(node, node.literal());
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTFloatingPointLiteral, java.lang.Object)
	 */
	@Override
	public Object visit(ASTFloatingPointLiteral node, Object data) {
		declareNode(node, node.value(null).toString());
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTIntegerLiteral, java.lang.Object)
	 */
	@Override
	public Object visit(ASTIntegerLiteral node, Object data) {
		declareNode(node, node.value(null).toString());
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTStringLiteral, java.lang.Object)
	 */
	@Override
	public Object visit(ASTStringLiteral node, Object data) {
		declareNode(node, "\"" + node.literal() + "\"");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTIdentifier, java.lang.Object)
	 */
	@Override
	public Object visit(ASTIdentifier node, Object data) {
		declareNode(node, node.literal());
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTWord, java.lang.Object)
	 */
	@Override
	public Object visit(ASTWord node, Object data) {
		declareNode(node, "keyword=" + node.literal());
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTDirective, java.lang.Object)
	 */
	@Override
	public Object visit(ASTDirective node, Object data) {
		declareNode(node, "directive=" + node.getDirectiveName());
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTBlock, java.lang.Object)
	 */
	@Override
	public Object visit(ASTBlock node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTMap, java.lang.Object)
	 */
	@Override
	public Object visit(ASTMap node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTObjectArray, java.lang.Object)
	 */
	@Override
	public Object visit(ASTObjectArray node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTIntegerRange, java.lang.Object)
	 */
	@Override
	public Object visit(ASTIntegerRange node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTMethod, java.lang.Object)
	 */
	@Override
	public Object visit(ASTMethod node, Object data) {
		declareNode(node, "method=" + node.getMethodName());
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTReference, java.lang.Object)
	 */
	@Override
	public Object visit(ASTReference node, Object data) {
		declareNode(node, "identifier=" + node.getRootString());
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTTrue, java.lang.Object)
	 */
	@Override
	public Object visit(ASTTrue node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTFalse, java.lang.Object)
	 */
	@Override
	public Object visit(ASTFalse node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTText, java.lang.Object)
	 */
	@Override
	public Object visit(ASTText node, Object data) {
		declareNode(node, NodeUtils.tokenLiteral(node.getFirstToken()));
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTIfStatement, java.lang.Object)
	 */
	@Override
	public Object visit(ASTIfStatement node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTElseStatement, java.lang.Object)
	 */
	@Override
	public Object visit(ASTElseStatement node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTElseIfStatement, java.lang.Object)
	 */
	@Override
	public Object visit(ASTElseIfStatement node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTSetDirective, java.lang.Object)
	 */
	@Override
	public Object visit(ASTSetDirective node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTStop, java.lang.Object)
	 */
	@Override
	public Object visit(ASTStop node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTExpression, java.lang.Object)
	 */
	@Override
	public Object visit(ASTExpression node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTAssignment, java.lang.Object)
	 */
	@Override
	public Object visit(ASTAssignment node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTOrNode, java.lang.Object)
	 */
	@Override
	public Object visit(ASTOrNode node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTAndNode, java.lang.Object)
	 */
	@Override
	public Object visit(ASTAndNode node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTEQNode, java.lang.Object)
	 */
	@Override
	public Object visit(ASTEQNode node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTNENode, java.lang.Object)
	 */
	@Override
	public Object visit(ASTNENode node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTLTNode, java.lang.Object)
	 */
	@Override
	public Object visit(ASTLTNode node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTGTNode, java.lang.Object)
	 */
	@Override
	public Object visit(ASTGTNode node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTLENode, java.lang.Object)
	 */
	@Override
	public Object visit(ASTLENode node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTGENode, java.lang.Object)
	 */
	@Override
	public Object visit(ASTGENode node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTAddNode, java.lang.Object)
	 */
	@Override
	public Object visit(ASTAddNode node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTSubtractNode, java.lang.Object)
	 */
	@Override
	public Object visit(ASTSubtractNode node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTMulNode, java.lang.Object)
	 */
	@Override
	public Object visit(ASTMulNode node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTDivNode, java.lang.Object)
	 */
	@Override
	public Object visit(ASTDivNode node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTModNode, java.lang.Object)
	 */
	@Override
	public Object visit(ASTModNode node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.apache.velocity.runtime.parser.node.ParserVisitor#visit(org.apache
	 * .velocity.runtime.parser.node.ASTNotNode, java.lang.Object)
	 */
	@Override
	public Object visit(ASTNotNode node, Object data) {
		declareNode(node, "");
		showNodeCommon(node);
		return null;
	}

}

test1.dot

digraph {
  node [fontsize=12, font=Courier, shape=ellipse]  node_0 [label="ASTprocess\n[templateName=vm/test1.vm]"]
  node_1 [label="ASTText\n[Testing iterative rendering contents:\r\n]"]
  node_0 -> node_1
  node_2 [label="ASTDirective\n[directive=foreach]"]
  node_0 -> node_2
  node_3 [label="ASTReference\n[identifier=i]"]
  node_2 -> node_3
  node_4 [label="ASTWord\n[keyword=in]"]
  node_2 -> node_4
  node_5 [label="ASTIntegerRange"]
  node_2 -> node_5
  node_6 [label="ASTIntegerLiteral\n[0]"]
  node_5 -> node_6
  node_7 [label="ASTIntegerLiteral\n[10]"]
  node_5 -> node_7
  node_8 [label="ASTBlock"]
  node_2 -> node_8
  node_9 [label="ASTSetDirective"]
  node_8 -> node_9
  node_10 [label="ASTReference\n[identifier=a]"]
  node_9 -> node_10
  node_11 [label="ASTExpression"]
  node_9 -> node_11
  node_12 [label="ASTAddNode"]
  node_11 -> node_12
  node_13 [label="ASTReference\n[identifier=i]"]
  node_12 -> node_13
  node_14 [label="ASTIntegerLiteral\n[1]"]
  node_12 -> node_14
  node_15 [label="ASTText\n[  ]"]
  node_8 -> node_15
  node_16 [label="ASTReference\n[identifier=i]"]
  node_8 -> node_16
  node_17 [label="ASTText\n[ is an ]"]
  node_8 -> node_17
  node_18 [label="ASTIfStatement"]
  node_8 -> node_18
  node_19 [label="ASTExpression"]
  node_18 -> node_19
  node_20 [label="ASTEQNode"]
  node_19 -> node_20
  node_21 [label="ASTModNode"]
  node_20 -> node_21
  node_22 [label="ASTReference\n[identifier=i]"]
  node_21 -> node_22
  node_23 [label="ASTIntegerLiteral\n[2]"]
  node_21 -> node_23
  node_24 [label="ASTIntegerLiteral\n[0]"]
  node_20 -> node_24
  node_25 [label="ASTBlock"]
  node_18 -> node_25
  node_26 [label="ASTText\n[even]"]
  node_25 -> node_26
  node_27 [label="ASTElseStatement"]
  node_18 -> node_27
  node_28 [label="ASTBlock"]
  node_27 -> node_28
  node_29 [label="ASTText\n[odd]"]
  node_28 -> node_29
  node_30 [label="ASTText\n[ number.\r\n]"]
  node_8 -> node_30
  node_31 [label="ASTText\n[Done testing\r\n]"]
  node_0 -> node_31
}

test1.vm

Testing iterative rendering contents:
#foreach ($i in [0..10])
  #set ($a = $i + 1)
  $i is an #if ($i % 2 == 0)even#{else}odd#end number.
#end
Done testing

TestDrive.java

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.io.Reader;

import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.Velocity;
import org.apache.velocity.context.InternalContextAdapter;
import org.apache.velocity.context.InternalContextAdapterImpl;
import org.apache.velocity.runtime.RuntimeSingleton;
import org.apache.velocity.runtime.parser.node.SimpleNode;

/**
 * Test ASTDotGenerator with a simple Velocity template.
 * 
 * @author RednaxelaFX
 *
 */
public class TestDrive {
	private static final String TEMPLATE_FILE_PATH = "vm/test1.vm";
	
	public static void main(String[] args) throws Exception {
		initVelocity();
		SimpleNode ast = getInitedAST();
		ASTDotGenerator dotGen = new ASTDotGenerator();
		String dot = dotGen.generateDot(ast);
		System.out.println(dot);
	}
	
	private static void initVelocity() throws Exception {
		Velocity.init();
	}
	
	private static SimpleNode getInitedAST() throws Exception {
		SimpleNode ast = RuntimeSingleton.parse(getTemplateReader(), TEMPLATE_FILE_PATH);
		InternalContextAdapter context = new InternalContextAdapterImpl(new VelocityContext());
		context.pushCurrentTemplateName(TEMPLATE_FILE_PATH);
		ast.init(context, RuntimeSingleton.getRuntimeServices());
		return ast;
	}
	
	private static Reader getTemplateReader() throws Exception {
		return new BufferedReader(new InputStreamReader(new FileInputStream(TEMPLATE_FILE_PATH)));
	}
}