JavaSyntaxRules.java #1

/*
 * JavaSyntaxRules.java
 *
 * comments here.
 *
 * @author   Michiaki Tatsubori
 * @version  %VERSION% %DATE%
 * @see      java.lang.Object
 *
 * COPYRIGHT 1998 by Michiaki Tatsubori, ALL RIGHTS RESERVED.
 */
package openjava.syntax;


import openjava.mop.Environment;
import openjava.tools.parser.*;
import openjava.ptree.*;
import openjava.ptree.util.*;


/**
 * The class <code>JavaSyntaxRules</code>
 * <p>
 * For example
 * <pre>
 * </pre>
 * <p>
 *
 * @author   Michiaki Tatsubori
 * @version  1.0
 * @since    %SOFTWARE% 1.0
 * @see java.lang.Object
 */
public class JavaSyntaxRules implements TokenID
{
    private JavaSyntaxRules() {}

    private static ParseException lastException = null;
    public static SyntaxException getLastException() {
	return new SyntaxException( lastException );
    }

    private static ParseTree correct( ParseTree ptree, Environment env ) {
	MemberAccessCorrector corrector
	    = new MemberAccessCorrector( env );
	ObjectList holder = new ObjectList( ptree );
	try {
	    ptree.accept( corrector );
	} catch ( ParseTreeException e ) {
	    System.err.println( e.getMessage() );
	}
	return (ParseTree) holder.get( 0 );
    }

    private static void
    adjustTokenSource( TokenSource token_src, Token last_token ) {
	Token token = token_src.getToken( 0 );
	while (token != last_token) {
	    token = token_src.getNextToken();
	}
	return; 
    }    

    /**
     * Consumes a single expression from given token source.
     *
     * @param token_src token source
     * @param env environment
     * @return  null if this fail, otherwise an expression.
     */
    public static final Expression
    consumeExpression( TokenSource token_src, Environment env ) {
	if (env == null)  env = token_src.getEnvironment();
	RestorableTokenSource dummy = new RestorableTokenSource( token_src );
	Parser parser = new Parser( dummy );
	try {
	    Expression ptree = parser.Expression( env );
	    adjustTokenSource( token_src, parser.getToken( 0 ) );
	    return (Expression) correct( ptree, env );
	} catch ( ParseException e ) {
	    lastException = e;
	    return null;
	}
    }
    public static final Expression
    consumeExpression( TokenSource token_src ) {
	return consumeExpression(  token_src, null );
    }

    /**
     * Consumes a statement.
     * This consumes only a pure statement excluding local variable
     * declarations and local class declarations.
     *
     * @param token_src token source
     * @return  null if this fail, otherwise a statement.
     */
    public static final Statement
    consumeStatement( TokenSource token_src, Environment env ) {
	if (env == null)  env = token_src.getEnvironment();
	RestorableTokenSource dummy = new RestorableTokenSource( token_src );
	Parser parser = new Parser( dummy );
	try {
	    Statement ptree = parser.Statement( env );
	    adjustTokenSource( token_src, parser.getToken( 0 ) );
	    return (Statement) correct( ptree, env );
	} catch ( ParseException e ) {
	    lastException = e;
	    return null;
	}
    }
    public static final Statement consumeStatement( TokenSource token_src ) {
	return consumeStatement(  token_src, token_src.getEnvironment() );
    }

    /**
     * Consumes a block.
     *
     * @param token_src token source
     * @return  null if this fail, otherwise a block.
     */
    public static final Block
    consumeBlock( TokenSource token_src, Environment env ) {
	if (env == null)  env = token_src.getEnvironment();
	RestorableTokenSource dummy = new RestorableTokenSource( token_src );
	Parser parser = new Parser( dummy );
	try {
	    Block ptree = parser.Block( env );
	    adjustTokenSource( token_src, parser.getToken( 0 ) );
	    return (Block) correct( ptree, env );
	} catch ( ParseException e ) {
	    lastException = e;
	    return null;
	}
    }
    public static final Block consumeBlock( TokenSource token_src ) {
	return consumeBlock(  token_src, token_src.getEnvironment() );
    }

    /**
     * Consumes a type name.
     * Including primitive type and reference type.
     *
     * @param token_src token source
     * @return  null if this fail, otherwise a block.
     */
    public static final TypeName
    consumeTypeName( TokenSource token_src ) {
	Environment env = token_src.getEnvironment();
	RestorableTokenSource dummy = new RestorableTokenSource( token_src );
	Parser parser = new Parser( dummy );
	try {
	    TypeName ptree = parser.Type( env );
	    adjustTokenSource( token_src, parser.getToken( 0 ) );
	    return (TypeName) correct( ptree, env );
	} catch ( ParseException e ) {
	    lastException = e;
	    return null;
	}
    }

}