Java Code Examples for org.apache.commons.jexl3.introspection.JexlMethod#invoke()

/**
 * Prints to output.
 * <p>
 * This will dynamically try to find the best suitable method in the writer through uberspection.
 * Subclassing Writer by adding 'print' methods should be the preferred way to specialize output.
 * </p>
 * @param info the source info
 * @param arg  the argument to print out
 */
private void doPrint(JexlInfo info, Object arg) {
    try {
        if (writer != null) {
            if (arg instanceof CharSequence) {
                writer.write(arg.toString());
            } else if (arg != null) {
                Object[] value = {arg};
                JexlUberspect uber = jexl.getUberspect();
                JexlMethod method = uber.getMethod(writer, "print", value);
                if (method != null) {
                    method.invoke(writer, value);
                } else {
                    writer.write(arg.toString());
                }
            }
        }
    } catch (java.io.IOException xio) {
        throw TemplateEngine.createException(info, "call print", null, xio);
    } catch (java.lang.Exception xany) {
        throw TemplateEngine.createException(info, "invoke print", null, xany);
    }
}
 

/**
 * Calculate the <code>size</code> of various types:
 * Collection, Array, Map, String, and anything that has a int size() method.
 * <p>Note that the result may not be an integer.
 *
 * @param node   the node that gave the value to size
 * @param object the object to get the size of
 * @return the evaluation result
 */
protected Object size(JexlNode node, Object object) {
    if (object == null) {
        return 0;
    }
    Object result = tryOverload(node, JexlOperator.SIZE, object);
    if (result != JexlEngine.TRY_FAILED) {
        return result;
    }
    final JexlArithmetic arithmetic = interpreter.arithmetic;
    result = arithmetic.size(object, null);
    if (result == null) {
        final JexlUberspect uberspect = interpreter.uberspect;
        // check if there is a size method on the object that returns an
        // integer and if so, just use it
        JexlMethod vm = uberspect.getMethod(object, "size", Interpreter.EMPTY_PARAMS);
        if (returnsInteger(vm)) {
            try {
                result = vm.invoke(object, Interpreter.EMPTY_PARAMS);
            } catch (Exception xany) {
                interpreter.operatorError(node, JexlOperator.SIZE, xany);
            }
        }
    }
    return result instanceof Number ? ((Number) result).intValue() : 0;
}
 

/**
 * Attempt to call close() if supported.
 * <p>This is used when dealing with auto-closeable (duck-like) objects
 * @param closeable the object we'd like to close
 */
protected void closeIfSupported(Object closeable) {
    if (closeable != null) {
        JexlMethod mclose = uberspect.getMethod(closeable, "close", EMPTY_PARAMS);
        if (mclose != null) {
            try {
                mclose.invoke(closeable, EMPTY_PARAMS);
            } catch (Exception xignore) {
                logger.warn(xignore);
            }
        }
    }
}
 

@Override
@SuppressWarnings("unchecked")
public Iterator<?> getIterator(Object obj) {
    if (obj instanceof Iterator<?>) {
        return ((Iterator<?>) obj);
    }
    if (obj.getClass().isArray()) {
        return new ArrayIterator(obj);
    }
    if (obj instanceof Map<?, ?>) {
        return ((Map<?, ?>) obj).values().iterator();
    }
    if (obj instanceof Enumeration<?>) {
        return new EnumerationIterator<Object>((Enumeration<Object>) obj);
    }
    if (obj instanceof Iterable<?>) {
        return ((Iterable<?>) obj).iterator();
    }
    try {
        // look for an iterator() method to support the JDK5 Iterable
        // interface or any user tools/DTOs that want to work in
        // foreach without implementing the Collection interface
        JexlMethod it = getMethod(obj, "iterator", (Object[]) null);
        if (it != null && Iterator.class.isAssignableFrom(it.getReturnType())) {
            return (Iterator<Object>) it.invoke(obj, (Object[]) null);
        }
    } catch (Exception xany) {
        if (logger != null && logger.isDebugEnabled()) {
            logger.info("unable to solve iterator()", xany);
        }
    }
    return null;
}
 

/**
 * Attempts to call an operator.
 * <p>
 * This takes care of finding and caching the operator method when appropriate
 * @param node     the syntactic node
 * @param operator the operator
 * @param args     the arguments
 * @return the result of the operator evaluation or TRY_FAILED
 */
protected Object tryOverload(JexlNode node, JexlOperator operator, Object... args) {
    if (operators != null && operators.overloads(operator)) {
        final JexlArithmetic arithmetic = interpreter.arithmetic;
        final boolean cache = interpreter.cache;
        try {
            if (cache) {
                Object cached = node.jjtGetValue();
                if (cached instanceof JexlMethod) {
                    JexlMethod me = (JexlMethod) cached;
                    Object eval = me.tryInvoke(operator.getMethodName(), arithmetic, args);
                    if (!me.tryFailed(eval)) {
                        return eval;
                    }
                }
            }
            JexlMethod vm = operators.getOperator(operator, args);
            if (vm != null && !isArithmetic(vm)) {
                Object result = vm.invoke(arithmetic, args);
                if (cache) {
                    node.jjtSetValue(vm);
                }
                return result;
            }
        } catch (Exception xany) {
            return interpreter.operatorError(node, operator, xany);
        }
    }
    return JexlEngine.TRY_FAILED;
}
 

/**
 * The 'startsWith' operator implementation.
 * @param node     the node
 * @param operator the calling operator, $= or $!
 * @param left     the left operand
 * @param right    the right operand
 * @return true if left starts with right, false otherwise
 */
protected boolean startsWith(JexlNode node, String operator, Object left, Object right) {
    final JexlArithmetic arithmetic = interpreter.arithmetic;
    final JexlUberspect uberspect = interpreter.uberspect;
    try {
        // try operator overload
        Object result = tryOverload(node, JexlOperator.STARTSWITH, left, right);
        if (result instanceof Boolean) {
            return (Boolean) result;
        }
        // use arithmetic / pattern matching ?
        Boolean matched = arithmetic.startsWith(left, right);
        if (matched != null) {
            return matched;
        }
        // try a startsWith method (duck type)
        try {
            Object[] argv = {right};
            JexlMethod vm = uberspect.getMethod(left, "startsWith", argv);
            if (returnsBoolean(vm)) {
                return (Boolean) vm.invoke(left, argv);
            } else if (arithmetic.narrowArguments(argv)) {
                vm = uberspect.getMethod(left, "startsWith", argv);
                if (returnsBoolean(vm)) {
                    return (Boolean) vm.invoke(left, argv);
                }
            }
        } catch (Exception e) {
            throw new JexlException(node, operator + " error", e);
        }
        // defaults to equal
        return arithmetic.equals(left, right) ? Boolean.TRUE : Boolean.FALSE;
    } catch (ArithmeticException xrt) {
        throw new JexlException(node, operator + " error", xrt);
    }
}
 

/**
 * The 'endsWith' operator implementation.
 * @param node     the node
 * @param operator the calling operator, ^= or ^!
 * @param left     the left operand
 * @param right    the right operand
 * @return true if left ends with right, false otherwise
 */
protected boolean endsWith(JexlNode node, String operator, Object left, Object right) {
    final JexlArithmetic arithmetic = interpreter.arithmetic;
    final JexlUberspect uberspect = interpreter.uberspect;
    try {
        // try operator overload
        Object result = tryOverload(node, JexlOperator.ENDSWITH, left, right);
        if (result instanceof Boolean) {
            return (Boolean) result;
        }
        // use arithmetic / pattern matching ?
        Boolean matched = arithmetic.endsWith(left, right);
        if (matched != null) {
            return matched;
        }
        // try a endsWith method (duck type)
        try {
            Object[] argv = {right};
            JexlMethod vm = uberspect.getMethod(left, "endsWith", argv);
            if (returnsBoolean(vm)) {
                return (Boolean) vm.invoke(left, argv);
            } else if (arithmetic.narrowArguments(argv)) {
                vm = uberspect.getMethod(left, "endsWith", argv);
                if (returnsBoolean(vm)) {
                    return (Boolean) vm.invoke(left, argv);
                }
            }
        } catch (Exception e) {
            throw new JexlException(node, operator + " error", e);
        }
        // defaults to equal
        return arithmetic.equals(left, right) ? Boolean.TRUE : Boolean.FALSE;
    } catch (ArithmeticException xrt) {
        throw new JexlException(node, operator + " error", xrt);
    }
}
 

/**
 * The 'match'/'in' operator implementation.
 * <p>
 * Note that 'x in y' or 'x matches y' means 'y contains x' ;
 * the JEXL operator arguments order syntax is the reverse of this method call.
 * </p>
 * @param node  the node
 * @param op    the calling operator, =~ or !~
 * @param right the left operand
 * @param left  the right operand
 * @return true if left matches right, false otherwise
 */
protected boolean contains(JexlNode node, String op, Object left, Object right) {
    final JexlArithmetic arithmetic = interpreter.arithmetic;
    final JexlUberspect uberspect = interpreter.uberspect;
    try {
        // try operator overload
        Object result = tryOverload(node, JexlOperator.CONTAINS, left, right);
        if (result instanceof Boolean) {
            return (Boolean) result;
        }
        // use arithmetic / pattern matching ?
        Boolean matched = arithmetic.contains(left, right);
        if (matched != null) {
            return matched;
        }
        // try a contains method (duck type set)
        try {
            Object[] argv = {right};
            JexlMethod vm = uberspect.getMethod(left, "contains", argv);
            if (returnsBoolean(vm)) {
                return (Boolean) vm.invoke(left, argv);
            } else if (arithmetic.narrowArguments(argv)) {
                vm = uberspect.getMethod(left, "contains", argv);
                if (returnsBoolean(vm)) {
                    return (Boolean) vm.invoke(left, argv);
                }
            }
        } catch (Exception e) {
            throw new JexlException(node, op + " error", e);
        }
        // defaults to equal
        return arithmetic.equals(left, right);
    } catch (ArithmeticException xrt) {
        throw new JexlException(node, op + " error", xrt);
    }
}
 

/**
 * Check for emptyness of various types: Collection, Array, Map, String, and anything that has a boolean isEmpty()
 * method.
 * <p>Note that the result may not be a boolean.
 *
 * @param node   the node holding the object
 * @param object the object to check the emptyness of
 * @return the evaluation result
 */
protected Object empty(JexlNode node, Object object) {
    if (object == null) {
        return true;
    }
    Object result = tryOverload(node, JexlOperator.EMPTY, object);
    if (result != JexlEngine.TRY_FAILED) {
        return result;
    }
    final JexlArithmetic arithmetic = interpreter.arithmetic;
    result = arithmetic.isEmpty(object, null);
    if (result == null) {
        final JexlUberspect uberspect = interpreter.uberspect;
        result = false;
        // check if there is an isEmpty method on the object that returns a
        // boolean and if so, just use it
        JexlMethod vm = uberspect.getMethod(object, "isEmpty", Interpreter.EMPTY_PARAMS);
        if (returnsBoolean(vm)) {
            try {
                result = vm.invoke(object, Interpreter.EMPTY_PARAMS);
            } catch (Exception xany) {
                interpreter.operatorError(node, JexlOperator.EMPTY, xany);
            }
        }
    }
    return result instanceof Boolean ? (Boolean) result : true;
}
 

/**
 * Resolves a namespace, eventually allocating an instance using context as constructor argument.
 * <p>
 * The lifetime of such instances span the current expression or script evaluation.</p>
 * @param prefix the prefix name (may be null for global namespace)
 * @param node   the AST node
 * @return the namespace instance
 */
protected Object resolveNamespace(String prefix, JexlNode node) {
    Object namespace;
    // check whether this namespace is a functor
    synchronized (this) {
        if (functors != null) {
            namespace = functors.get(prefix);
            if (namespace != null) {
                return namespace;
            }
        }
    }
    // check if namespace is a resolver
    namespace = ns.resolveNamespace(prefix);
    if (namespace == null) {
        namespace = functions.get(prefix);
        if (prefix != null && namespace == null) {
            throw new JexlException(node, "no such function namespace " + prefix, null);
        }
    }
    // shortcut if ns is known to be not-a-functor
    final boolean cacheable = cache;
    Object cached = cacheable ? node.jjtGetValue() : null;
    if (cached != JexlContext.NamespaceFunctor.class) {
        // allow namespace to instantiate a functor with context if possible, not an error otherwise
        Object functor = null;
        if (namespace instanceof JexlContext.NamespaceFunctor) {
            functor = ((JexlContext.NamespaceFunctor) namespace).createFunctor(context);
        } else if (namespace instanceof Class<?> || namespace instanceof String) {
            // attempt to reuse last ctor cached in volatile JexlNode.value
            if (cached instanceof JexlMethod) {
                try {
                    Object eval = ((JexlMethod) cached).tryInvoke(null, context);
                    if (JexlEngine.TRY_FAILED != eval) {
                        functor = eval;
                    }
                } catch (JexlException.TryFailed xtry) {
                    throw new JexlException(node, "unable to instantiate namespace " + prefix, xtry.getCause());
                }
            }
            if (functor == null) {
                JexlMethod ctor = uberspect.getConstructor(namespace, context);
                if (ctor != null) {
                    try {
                        functor = ctor.invoke(namespace, context);
                        if (cacheable && ctor.isCacheable()) {
                            node.jjtSetValue(ctor);
                        }
                    } catch (Exception xinst) {
                        throw new JexlException(node, "unable to instantiate namespace " + prefix, xinst);
                    }
                }
            }
        }
        // got a functor, store it and return it
        if (functor != null) {
            synchronized (this) {
                if (functors == null) {
                    functors = new HashMap<String, Object>();
                }
                functors.put(prefix, functor);
            }
            return functor;
        } else {
            // use the NamespaceFunctor class to tag this node as not-a-functor
            node.jjtSetValue(JexlContext.NamespaceFunctor.class);
        }
    }
    return namespace;
}
 

@Test
public void testMethodIntrospection() throws Exception {
    Uberspect uber = new Uberspect(null, null);
    Bulgroz bulgroz = new Bulgroz();
    JexlMethod jmethod;
    Object result;
    jmethod = uber.getMethod(bulgroz, "list", 0);
    result = jmethod.invoke(bulgroz, 0);
    Assert.assertEquals(0, result);
    jmethod = uber.getMethod(bulgroz, "list", "1");
    result = jmethod.invoke(bulgroz, "1");
    Assert.assertEquals(1, result);
    jmethod = uber.getMethod(bulgroz, "list", bulgroz);
    result = jmethod.invoke(bulgroz, bulgroz);
    Assert.assertEquals(2, result);
    jmethod = uber.getMethod(bulgroz, "list", 1, bulgroz);
    result = jmethod.invoke(bulgroz, 1, bulgroz);
    Assert.assertEquals(3, result);
    jmethod = uber.getMethod(bulgroz, "list", 1, bulgroz, bulgroz);
    result = jmethod.invoke(bulgroz, 1, bulgroz, bulgroz);
    Assert.assertEquals(3, result);
    jmethod = uber.getMethod(bulgroz, "list", 1, 2);
    result = jmethod.invoke(bulgroz, 1, 2);
    Assert.assertEquals(4, result);
    jmethod = uber.getMethod(bulgroz, "list", "1", bulgroz);
    result = jmethod.invoke(bulgroz, "1", bulgroz);
    Assert.assertEquals(5, result);
    jmethod = uber.getMethod(bulgroz, "list", "1", "2");
    result = jmethod.invoke(bulgroz, "1", "2");
    Assert.assertEquals(6, result);
    jmethod = uber.getMethod(bulgroz, "list", bulgroz, bulgroz);
    result = jmethod.invoke(bulgroz, bulgroz, bulgroz);
    Assert.assertEquals(8, result);
    jmethod = uber.getMethod(bulgroz, "list", bulgroz, 1, bulgroz);
    result = jmethod.invoke(bulgroz, bulgroz, 1, bulgroz);
    Assert.assertEquals(7, result);
    jmethod = uber.getMethod(bulgroz, "list", bulgroz, 1, "1");
    result = jmethod.invoke(bulgroz, bulgroz, 1, "1");
    Assert.assertEquals(7, result);
    jmethod = uber.getMethod(bulgroz, "list", (Object) null);
    result = jmethod.invoke(bulgroz,  (Object) null);
    Assert.assertEquals(2, result);
    jmethod = uber.getMethod(bulgroz, "list", bulgroz, (Object) null);
    result = jmethod.invoke(bulgroz, bulgroz, (Object) null);
    Assert.assertEquals(8, result);
    jmethod = uber.getMethod(bulgroz, "list", null, "1");
    result = jmethod.invoke(bulgroz, null, "1");
    Assert.assertEquals(8, result);
    jmethod = uber.getMethod(bulgroz, "list", bulgroz, null, null);
    result = jmethod.invoke(bulgroz, bulgroz, null, null);
    Assert.assertEquals(7, result);

    jmethod = uber.getMethod(bulgroz, "amb", 3d);
    Assert.assertNotNull(null, jmethod);
}