Examples with STRING_TYPE org.codehaus.groovy.ast.ClassHelper.STRING_TYPE used on opensource projects

Example 1 with STRING_TYPE

use of org.codehaus.groovy.ast.ClassHelper.STRING_TYPE in project groovy by apache.

the class StaticTypeCheckingSupport method evaluateExpression.

/**
 * A helper method that can be used to evaluate expressions as found in annotation
 * parameters. For example, it will evaluate a constant, be it referenced directly as
 * an integer or as a reference to a field.
 * <p>
 * If this method throws an exception, then the expression cannot be evaluated on its own.
 *
 * @param expr   the expression to be evaluated
 * @param config the compiler configuration
 * @return the result of the expression
 */
public static Object evaluateExpression(final Expression expr, final CompilerConfiguration config) {
    Expression ce = expr instanceof CastExpression ? ((CastExpression) expr).getExpression() : expr;
    if (ce instanceof ConstantExpression) {
        if (expr.getType().equals(ce.getType()))
            return ((ConstantExpression) ce).getValue();
    } else if (ce instanceof ListExpression) {
        if (expr.getType().isArray() && expr.getType().getComponentType().equals(STRING_TYPE))
            return ((ListExpression) ce).getExpressions().stream().map(e -> evaluateExpression(e, config)).toArray(String[]::new);
    }
    String className = "Expression$" + UUID.randomUUID().toString().replace('-', '$');
    ClassNode simpleClass = new ClassNode(className, Opcodes.ACC_PUBLIC, OBJECT_TYPE);
    addGeneratedMethod(simpleClass, "eval", Opcodes.ACC_PUBLIC + Opcodes.ACC_STATIC, OBJECT_TYPE, Parameter.EMPTY_ARRAY, ClassNode.EMPTY_ARRAY, new ReturnStatement(expr));
    // adjust configuration so class can be inspected by this JVM
    CompilerConfiguration cc = new CompilerConfiguration(config);
    // unlikely to be required by expression
    cc.setPreviewFeatures(false);
    cc.setTargetBytecode(CompilerConfiguration.DEFAULT.getTargetBytecode());
    CompilationUnit cu = new CompilationUnit(cc);
    try {
        cu.addClassNode(simpleClass);
        cu.compile(Phases.CLASS_GENERATION);
        List<GroovyClass> classes = cu.getClasses();
        Class<?> aClass = cu.getClassLoader().defineClass(className, classes.get(0).getBytes());
        try {
            return aClass.getMethod("eval").invoke(null);
        } catch (ReflectiveOperationException e) {
            throw new GroovyBugError(e);
        }
    } finally {
        closeQuietly(cu.getClassLoader());
    }
}