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/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* License: GNU Lesser General Public License (LGPL), version 2.1 or later.
* See the lgpl.txt file in the root directory or .
*/
package org.hibernate.hql.internal.ast.util;
import java.io.ByteArrayOutputStream;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import org.hibernate.hql.internal.ast.tree.DisplayableNode;
import org.hibernate.internal.util.StringHelper;
import antlr.collections.AST;
/**
* Utility for generating pretty "ASCII art" representations of syntax trees.
*
* This class is threadsafe: reuse instances as needed.
*
* @author Joshua Davis
* @author Steve Ebersole
*/
public class ASTPrinter {
// This is a map: array index is the ANTLR Token ID, array value is the name of that token.
// There might be gaps in the array (null values) but it's generally quite compact.
private final String[] tokenTypeNameCache;
/**
* Constructs a printer. Package protected: use the constants from {TokenPrinters}
* @see TokenPrinters
*
* @param tokenTypeConstants The token types to use during printing; typically the {vocabulary}TokenTypes.java
* interface generated by ANTLR.
*/
ASTPrinter(Class tokenTypeConstants) {
this.tokenTypeNameCache = ASTUtil.generateTokenNameCache( tokenTypeConstants );
}
/**
* Renders the AST into 'ASCII art' form and returns that string representation.
*
* @param ast The AST to display.
* @param header The header for the display.
*
* @return The AST in 'ASCII art' form, as a string.
*/
public String showAsString(AST ast, String header) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
PrintStream ps = new PrintStream( baos );
ps.println( header );
showAst( ast, ps );
ps.flush();
return new String( baos.toByteArray() );
}
/**
* Prints the AST in 'ASCII art' form to the specified print stream.
*
* @param ast The AST to print.
* @param out The print stream to which the AST should be printed.
*/
public void showAst(AST ast, PrintStream out) {
showAst( ast, new PrintWriter( out ) );
}
/**
* Prints the AST in 'ASCII art' tree form to the specified print writer.
*
* @param ast The AST to print.
* @param pw The print writer to which the AST should be written.
*/
public void showAst(AST ast, PrintWriter pw) {
ArrayList parents = new ArrayList();
showAst( parents, pw, ast );
pw.flush();
}
/**
* Returns the token type name for the given token type.
*
* @param type The token type.
*
* @return String - The token type name from the token type constant class,
* or just the integer as a string if none exists.
*/
public String getTokenTypeName(int type) {
String value = tokenTypeNameCache[type];
if ( value == null ) {
value = Integer.toString( type );
}
return value;
}
private void showAst(ArrayList parents, PrintWriter pw, AST ast) {
if ( ast == null ) {
pw.println( "AST is null!" );
return;
}
indentLine( parents, pw );
if ( ast.getNextSibling() == null ) {
pw.print( " \\-" );
}
else {
pw.print( " +-" );
}
showNode( pw, ast );
showNodeProperties( parents, pw, ast );
ArrayList newParents = new ArrayList( parents );
newParents.add( ast );
for ( AST child = ast.getFirstChild(); child != null; child = child.getNextSibling() ) {
showAst( newParents, pw, child );
}
newParents.clear();
}
private void indentLine(List parents, PrintWriter pw) {
for ( AST parent : parents ) {
if ( parent.getNextSibling() == null ) {
pw.print( " " );
}
else {
pw.print( " | " );
}
}
}
private void showNode(PrintWriter pw, AST ast) {
String s = nodeToString( ast );
pw.println( s );
}
public String nodeToString(AST ast) {
if ( ast == null ) {
return "{node:null}";
}
StringBuilder buf = new StringBuilder();
buf.append( "[" ).append( getTokenTypeName( ast.getType() ) ).append( "] " );
buf.append( StringHelper.unqualify( ast.getClass().getName() ) ).append( ": " );
buf.append( "'" );
String text = ast.getText();
if ( text == null ) {
text = "{text:null}";
}
appendEscapedMultibyteChars( text, buf );
buf.append( "'" );
if ( ast instanceof DisplayableNode ) {
DisplayableNode displayableNode = (DisplayableNode) ast;
// Add a space before the display text.
buf.append( " " ).append( displayableNode.getDisplayText() );
}
return buf.toString();
}
private void showNodeProperties(ArrayList parents, PrintWriter pw, AST ast) {
Map nodeProperties = createNodeProperties( ast );
ArrayList parentsAndNode = new ArrayList<>( parents );
parentsAndNode.add( ast );
for ( String propertyName : nodeProperties.keySet() ) {
indentLine( parentsAndNode, pw );
pw.println( propertyToString( propertyName, nodeProperties.get( propertyName ), ast ) );
}
}
public LinkedHashMap createNodeProperties(AST ast) {
return new LinkedHashMap<>();
}
public String propertyToString(String label, Object value, AST ast) {
return String.format( "%s: %s", label, value );
}
public static void appendEscapedMultibyteChars(String text, StringBuilder buf) {
char[] chars = text.toCharArray();
for ( char aChar : chars ) {
if ( aChar > 256 ) {
buf.append( "\\u" );
buf.append( Integer.toHexString( aChar ) );
}
else {
buf.append( aChar );
}
}
}
public static String escapeMultibyteChars(String text) {
StringBuilder buf = new StringBuilder();
appendEscapedMultibyteChars( text, buf );
return buf.toString();
}
}