Dépôt officiel du code source de l'ERP OpenConcerto

/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

 *

 * Copyright 2011 OpenConcerto, by ILM Informatique. All rights reserved.

 *

 * The contents of this file are subject to the terms of the GNU General Public License Version 3

 * only ("GPL"). You may not use this file except in compliance with the License. You can obtain a

 * copy of the License at http://www.gnu.org/licenses/gpl-3.0.html See the License for the specific

 * language governing permissions and limitations under the License.

 *

 * When distributing the software, include this License Header Notice in each file.

 */

 package org.openconcerto.xml;

import org.openconcerto.utils.StringUtils;

import org.openconcerto.utils.cache.CacheResult;

import org.openconcerto.utils.cache.ICache;

import org.openconcerto.utils.cc.ExnTransformer;

import java.beans.XMLDecoder;

import java.beans.XMLEncoder;

import java.lang.reflect.Array;

import java.lang.reflect.Constructor;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.LinkedList;

import java.util.List;

import java.util.Map;

import java.util.Stack;

/**

 * To decode XML in {@link XMLEncoder} format.

 *

 * @author Sylvain CUAZ

 * @param <S> type of source

 * @param <E> type of exception

 */

public abstract class AbstractXMLDecoder<S, E extends Exception> {

    protected static interface Children<C> {

        C getNextChild();

    }

    private static final ICache<Object, Method, Object> cache = new ICache<Object, Method, Object>(60, -1, "methods for " + XMLCodecUtils.class);

    private static final ICache<Object, Constructor<?>, Object> cacheCtor = new ICache<Object, Constructor<?>, Object>(60, -1, "constructors for " + XMLCodecUtils.class);

    protected abstract String getLocalName(S elem);

    protected abstract String getAttributeValue(S elem, final String attrName);

    protected abstract String getElementText(S elem) throws E;

    protected abstract S getFirstChild(S elem);

    protected abstract String toString(S elem);

    protected abstract Children<S> createChildren(S elem) throws E;

    public final <K, V> Map<K, V> decodeFromArray(final S elem, final Class<K> keyClass, final Class<V> valueClass) {

        return XMLCodecUtils.decodeFromArray((Object[]) this.decode1(elem), keyClass, valueClass);

    }

    /**

     * Tries to decode an xml element parsed from a string obtained from XMLEncoder. This doesn't

     * use {@link XMLDecoder} as it requires outputting it first to string which is inefficient.

     * NOTE: this decoder supports only a subset of XMLDecoder.

     *

     * @param javaElem a "java" element.

     * @return the decoded object.

     */

    public final Object decode1(S javaElem) {

        final S elem = getFirstChild(javaElem);

        try {

            return eval(elem, new Stack<Object>(), new HashMap<String, Object>());

        } catch (Exception e) {

            throw new IllegalStateException("error decoding " + toString(javaElem), e);

        }

    }

    private final Object eval(S elem, Stack<Object> context, final Map<String, Object> ids)

            throws ClassNotFoundException, InstantiationException, IllegalAccessException, InvocationTargetException, E {

        preEval(elem);

        final Object res = this._eval(elem, context, ids);

        postEval(elem, res);

        return res;

    }

    protected void preEval(S elem) throws E {

    }

    protected void nullDecoded(S elem) throws E {

    }

    protected void idRefDecoded(S elem) throws E {

    }

    protected void postEval(S elem, final Object res) throws E {

    }

    private final Object _eval(S elem, Stack<Object> context, final Map<String, Object> ids)

            throws ClassNotFoundException, InstantiationException, IllegalAccessException, InvocationTargetException, E {

        final String n = getLocalName(elem);

        // Ordered from real world scenario

        // string : 80k

        // void : 53k

        // int : 18k

        // object : 9k

        // null : 6k

        switch (n) {

        case "string":

            return getElementText(elem);

        case "void":

        case "object":

            final String idref = getAttributeValue(elem, "idref");

            if (idref != null) {

                if (!ids.containsKey(idref))

                    throw new IllegalStateException("id '" + idref + "' wasn't defined");

                idRefDecoded(elem);

                return ids.get(idref);

            }

            final String id = getAttributeValue(elem, "id");

            final String targetClass = getAttributeValue(elem, "class");

            final Object target = targetClass == null ? context.peek() : Class.forName(targetClass);

            final String propAttr = getAttributeValue(elem, "property");

            final String indexAttr = getAttributeValue(elem, "index");

            final String methodAttr = getAttributeValue(elem, "method");

            final String fieldAttr = getAttributeValue(elem, "field");

            // statement or expression

            final Object res = evalContainer(elem, context, ids, new ExnTransformer<List<Object>, Object, Exception>() {

                @Override

                public Object transformChecked(List<Object> args) throws Exception {

                    // call the statement

                    final Object res;

                    if (propAttr != null) {

                        final String methodName = (args.size() == 0 ? "get" : "set") + StringUtils.firstUp(propAttr);

                        res = invoke(target, methodName, args);

                    } else if (indexAttr != null) {

                        final String methodName;

                        if (target instanceof List) {

                            methodName = args.size() == 0 ? "get" : "set";

                            // get(index) or set(index, value)

                            args.add(0, Integer.valueOf(indexAttr));

                            res = invoke(target, methodName, args);

                        } else if (target.getClass().isArray()) {

                            final Class<?> componentType = target.getClass().getComponentType();

                            // in Array there's set(array, int index, Object value) or

                            // setPrimitive(array, int index, primitive value)

                            methodName = (args.size() == 0 ? "get" : "set") + (componentType.isPrimitive() ? StringUtils.firstUp(componentType.getSimpleName()) : "");

                            args.add(0, target);

                            args.add(1, Integer.valueOf(indexAttr));

                            res = invoke(Array.class, methodName, args);

                        } else

                            throw new IllegalStateException("use index with neither List nor array: " + target);

                    } else if (methodAttr != null) {

                        res = invoke(target, methodAttr, args);

                    } else if (fieldAttr != null) {

                        res = ((Class<?>) target).getField(fieldAttr).get(null);

                    } else {

                        res = getCtor((Class<?>) target, args).newInstance(args.toArray());

                    }

                    return res;

                }

            });

            // not very functional but it works

            if (id != null)

                ids.put(id, res);

            return res;

        case "int":

            return Integer.valueOf(getElementText(elem));

        case "null":

            nullDecoded(elem);

            return null;

        case "boolean":

            return Boolean.valueOf(getElementText(elem));

        case "byte":

            return Byte.valueOf(getElementText(elem));

        case "char":

            return Character.valueOf(getElementText(elem).charAt(0));

        case "short":

            return Short.valueOf(getElementText(elem));

        case "long":

            return Long.valueOf(getElementText(elem));

        case "float":

            return Float.valueOf(getElementText(elem));

        case "double":

            return Double.valueOf(getElementText(elem));

        case "array":

            final String classAttr = getAttributeValue(elem, "class");

            final String lengthAttr = getAttributeValue(elem, "length");

            final Class<?> componentClass = parseClassName(classAttr);

            if (lengthAttr != null) {

                context.push(Array.newInstance(componentClass, Integer.parseInt(lengthAttr)));

                final Children<S> children = createChildren(elem);

                S child;

                while ((child = children.getNextChild()) != null) {

                    eval(child, context, ids);

                }

                return context.pop();

            } else {

                final List<Object> items = new LinkedList<>();

                final Children<S> children = createChildren(elem);

                S child;

                while ((child = children.getNextChild()) != null) {

                    items.add(eval(child, context, ids));

                }

                final Object resArray = Array.newInstance(componentClass, items.size());

                int i = 0;

                for (final Object item : items)

                    Array.set(resArray, i++, item);

                return resArray;

            }

        case "class":

            return Class.forName(getElementText(elem));

        default:

            throw new UnsupportedOperationException("doesn't yet support " + n);

        }

    }

    private final Object evalContainer(final S parent, Stack<Object> context, final Map<String, Object> ids, final ExnTransformer<List<Object>, Object, ? extends Exception> transf)

            throws ClassNotFoundException, InstantiationException, IllegalAccessException, InvocationTargetException, E {

        final List<Object> args = new ArrayList<Object>();

        final Children<S> children = createChildren(parent);

        boolean noVoid = true;

        S child = null;

        while (noVoid && (child = children.getNextChild()) != null) {

            if (getLocalName(child).equals("void"))

                noVoid = false;

            else {

                args.add(eval(child, context, ids));

            }

        }

        // call the statement

        final Object res = transf.transformCheckedWithExn(args, false, InvocationTargetException.class, InstantiationException.class, IllegalAccessException.class);

        context.push(res);

        // now call the voids

        if (child != null) {

            do {

                eval(child, context, ids);

            } while ((child = children.getNextChild()) != null);

        }

        return context.pop();

    }

    private static final Object invoke(final Object target, String methodName, final List<Object> args) throws IllegalAccessException, InvocationTargetException {

        // <object class="Cell" method="createEmpty" >

        // for static methods the target is already a class

        final Class clazz = target instanceof Class ? (Class) target : target.getClass();

        final Method m = getMethod(clazz, methodName, args);

        return m.invoke(target, args.toArray());

    }

    private static final Method getMethod(Class<?> clazz, String name, List<Object> actualArgs) {

        final List<Class<?>> actualClasses = objectsToClasses(actualArgs);

        final List<Object> key = new ArrayList<Object>(3);

        key.add(clazz);

        key.add(name);

        key.add(actualClasses);

        final CacheResult<Method> cacheRes = cache.check(key);

        if (cacheRes.getState() == CacheResult.State.VALID)

            return cacheRes.getRes();

        final Method res = findMethod(clazz, name, actualClasses);

        if (res == null)

            throw new IllegalStateException("No matching method " + name + " found in " + clazz);

        cache.put(key, res);

        return res;

    }

    private static final Constructor getCtor(Class<?> clazz, List<Object> actualArgs) {

        final List<Class<?>> actualClasses = objectsToClasses(actualArgs);

        final List<Object> key = new ArrayList<Object>(3);

        key.add(clazz);

        key.add(actualClasses);

        final CacheResult<Constructor<?>> cacheRes = cacheCtor.check(key);

        if (cacheRes.getState() == CacheResult.State.VALID)

            return cacheRes.getRes();

        final Constructor res = findCtor(clazz, actualClasses);

        if (res == null)

            throw new IllegalStateException("No constructor in " + clazz + " for arguments " + actualClasses);

        cacheCtor.put(key, res);

        return res;

    }

    private static final List<Class<?>> objectsToClasses(List<Object> actualArgs) {

        final List<Class<?>> actualClasses = new ArrayList<Class<?>>(actualArgs.size());

        for (final Object actualArg : actualArgs)

            actualClasses.add(actualArg == null ? null : actualArg.getClass());

        return actualClasses;

    }

    // TODO return the most specific matching method instead of the first one

    // (handle both Sub/Superclass and primitive/object type)

    private static final Method findMethod(Class<?> clazz, String name, List<Class<?>> actualArgs) {

        for (final Method m : clazz.getMethods()) {

            if (m.getName().equals(name) && callableWith(m.getParameterTypes(), actualArgs)) {

                return m;

            }

        }

        return null;

    }

    // TODO see findMethod()

    private static final Constructor findCtor(Class<?> clazz, List<Class<?>> actualArgs) {

        for (final Constructor m : clazz.getConstructors()) {

            if (callableWith(m.getParameterTypes(), actualArgs)) {

                return m;

            }

        }

        return null;

    }

    private static final boolean callableWith(Class<?>[] formalArgs, List<Class<?>> actualArgs) {

        if (formalArgs.length != actualArgs.size())

            return false;

        int i = 0;

        for (final Class<?> argClass : formalArgs) {

            final Class<?> actualArg = actualArgs.get(i);

            // null match everything

            if (actualArg != null && !argClass.isAssignableFrom(actualArg) && argClass != getPrimitive(actualArg))

                return false;

            i++;

        }

        return true;

    }

    private static Class<?> getPrimitive(Class<?> argClass) {

        if (argClass == Boolean.class)

            return Boolean.TYPE;

        else if (argClass == Character.class)

            return Character.TYPE;

        else if (argClass == Byte.class)

            return Byte.TYPE;

        else if (argClass == Short.class)

            return Short.TYPE;

        else if (argClass == Integer.class)

            return Integer.TYPE;

        else if (argClass == Long.class)

            return Long.TYPE;

        else if (argClass == Float.class)

            return Float.TYPE;

        else if (argClass == Double.class)

            return Double.TYPE;

        else

            return null;

    }

    private static final Map<String, Class> primitiveNames = new HashMap<String, Class>();

    static {

        primitiveNames.put("boolean", boolean.class);

        primitiveNames.put("byte", byte.class);

        primitiveNames.put("char", char.class);

        primitiveNames.put("short", short.class);

        primitiveNames.put("int", int.class);

        primitiveNames.put("long", long.class);

        primitiveNames.put("float", float.class);

        primitiveNames.put("double", double.class);

    }

    /**

     * Parse class names (including primitive).

     *

     * @param className a class name, eg "java.lang.String" or "int".

     * @return the matching class, eg java.lang.String.class or Integer.TYPE.

     * @throws ClassNotFoundException if the passed name doesn't exist.

     */

    private static Class<?> parseClassName(String className) throws ClassNotFoundException {

        final Class<?> primitive = primitiveNames.get(className);

        if (primitive != null)

            return primitive;

        else

            return Class.forName(className);

    }

}