Groovy example source code file (VerifierCodeVisitor.java)

This example Groovy source code file (VerifierCodeVisitor.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Groovy tags/keywords

classnode, codevisitorsupport, identifier, invalid, invalid, must, must, no, runtimeparserexception, runtimeparserexception, string, verifier, verifiercodevisitor, verifiercodevisitor

The Groovy VerifierCodeVisitor.java source code

/*
 * Copyright 2003-2010 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.codehaus.groovy.classgen;

import org.codehaus.groovy.ast.ASTNode;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.CodeVisitorSupport;
import org.codehaus.groovy.ast.stmt.ForStatement;
import org.codehaus.groovy.ast.expr.ConstructorCallExpression;
import org.codehaus.groovy.ast.expr.Expression;
import org.codehaus.groovy.ast.expr.ListExpression;
import org.codehaus.groovy.ast.expr.MapEntryExpression;
import org.codehaus.groovy.ast.expr.FieldExpression;
import org.codehaus.groovy.ast.expr.VariableExpression;
import org.codehaus.groovy.syntax.RuntimeParserException;
import org.objectweb.asm.Opcodes;

/**
 * Performs various checks on code inside methods and constructors
 * including checking for valid field, variables names etc. that
 * would otherwise lead to invalid code.
 *
 * @author <a href="mailto:james@coredevelopers.net">James Strachan
 * @version $Revision: 20213 $
 */
public class VerifierCodeVisitor extends CodeVisitorSupport implements Opcodes {

    private Verifier verifier;

    VerifierCodeVisitor(Verifier verifier) {
        this.verifier = verifier;
    }

    public void visitForLoop(ForStatement expression) {
        assertValidIdentifier(expression.getVariable().getName(), "for loop variable name", expression);
        super.visitForLoop(expression);
    }

    public void visitFieldExpression(FieldExpression expression) {
        if (!expression.getField().isSynthetic()) {
            assertValidIdentifier(expression.getFieldName(), "field name", expression);
        }
        super.visitFieldExpression(expression);
    }

    public void visitVariableExpression(VariableExpression expression) {
        assertValidIdentifier(expression.getName(), "variable name", expression);
        super.visitVariableExpression(expression);
    }

    public void visitListExpression(ListExpression expression) {
        for (Expression element : expression.getExpressions()) {
            if (element instanceof MapEntryExpression) {
                throw new RuntimeParserException("No map entry allowed at this place", element);
            }
        }
        super.visitListExpression(expression);
    }

    public void visitConstructorCallExpression(ConstructorCallExpression call) {
        ClassNode callType = call.getType();
        if (callType.isEnum() && !callType.equals(verifier.getClassNode())) {
            throw new RuntimeParserException("Enum constructor calls are only allowed inside the enum class", call);
        }
    }

    public static void assertValidIdentifier(String name, String message, ASTNode node) {
        int size = name.length();
        if (size <= 0) {
            throw new RuntimeParserException("Invalid " + message + ". Identifier must not be empty", node);
        }
        char firstCh = name.charAt(0);
        if (size == 1 && firstCh == '$') {
            throw new RuntimeParserException("Invalid " + message + ". Must include a letter but only found: " + name, node);
        }
        if (!Character.isJavaIdentifierStart(firstCh)) {
            throw new RuntimeParserException("Invalid " + message + ". Must start with a letter but was: " + name, node);
        }

        for (int i = 1; i < size; i++) {
            char ch = name.charAt(i);
            if (!Character.isJavaIdentifierPart(ch)) {
                throw new RuntimeParserException("Invalid " + message + ". Invalid character at position: " + (i + 1) + " of value:  " + ch + " in name: " + name, node);
            }
        }
    }
}