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.CollectionUtils;

import org.openconcerto.xml.Step.Axis;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collections;

import java.util.Iterator;

import java.util.List;

import org.jdom.Attribute;

import org.jdom.Element;

import org.jdom.filter.Filter;

import org.jdom.xpath.XPath;

/**

 * Like an {@link XPath} with less features but a greater speed. Thread-safe if its {@link Step

 * steps} are.

 *

 * @author Sylvain CUAZ

 *

 * @param <T> type of result.

 */

public final class SimpleXMLPath<T> {

    private static final SimpleXMLPath<Attribute> ALL_ATTRIBUTES = allAttributes(null, null);

    private static final SimpleXMLPath<Element> ALL_ELEMENTS = allElements(null, null);

    public static <T> SimpleXMLPath<T> create(final List<Step<?>> steps, final Step<T> lastStep) {

        return new SimpleXMLPath<T>(Collections.unmodifiableList(new ArrayList<Step<?>>(steps)), lastStep);

    }

    public static <T> SimpleXMLPath<T> create(final Step<T> lastStep) {

        return new SimpleXMLPath<T>(Collections.<Step<?>> emptyList(), lastStep);

    }

    public static <T> SimpleXMLPath<T> create(final Step<?> first, final Step<T> lastStep) {

        return new SimpleXMLPath<T>(Collections.<Step<?>> singletonList(first), lastStep);

    }

    public static <T> SimpleXMLPath<T> create(final Step<?> first, final Step<?> second, final Step<T> lastStep) {

        return new SimpleXMLPath<T>(Arrays.<Step<?>> asList(first, second), lastStep);

    }

    /**

     * Create a path searching for all descendant attributes. The returned instance is immutable.

     *

     * @return a path searching attributes in all {@link Axis#descendantOrSelf} elements.

     */

    public static SimpleXMLPath<Attribute> allAttributes() {

        return ALL_ATTRIBUTES;

    }

    /**

     * Create a path searching for all descendant attributes with the passed name and namespace.

     * I.e. in XPath this would be ".//@ns:name". The returned instance is immutable.

     *

     * @param name the name of attributes.

     * @param ns the namespace of attributes.

     * @return a path searching attributes in all {@link Axis#descendantOrSelf} elements.

     */

    public static SimpleXMLPath<Attribute> allAttributes(final String name, final String ns) {

        return create(Step.createElementStep(Axis.descendantOrSelf, null), Step.createAttributeStep(name, ns));

    }

    /**

     * Create a path searching for all descendant elements. The returned instance is immutable.

     *

     * @return a path searching all {@link Axis#descendantOrSelf} elements.

     */

    public static SimpleXMLPath<Element> allElements() {

        return ALL_ELEMENTS;

    }

    /**

     * Create a path searching for all descendant elements with the passed name and namespace. I.e.

     * in XPath this would be ".//ns:name". The returned instance is immutable.

     *

     * @param name the name of elements.

     * @param ns the namespace of elements.

     * @return a path searching all {@link Axis#descendantOrSelf} elements.

     */

    public static SimpleXMLPath<Element> allElements(final String name, final String ns) {

        return create(Step.createElementStep(Axis.descendantOrSelf, name, ns));

    }

    private final List<Step<?>> items;

    private final Step<T> lastItem;

    // private since we don't copy steps

    private SimpleXMLPath(final List<Step<?>> steps, Step<T> lastStep) {

        this.lastItem = lastStep;

        this.items = steps;

    }

    // return Element or Attribute

    public final T selectSingleNode(final Object n) {

        return selectSingleNode(n, this.items);

    }

    private final T selectSingleNode(final Object currentNode, List<Step<?>> steps) {

        final int size = steps.size();

        if (size > 0) {

            final Step<?> currentStep = steps.get(0);

            final List<?> nextNodes = currentStep.nextNodes(Node.get(currentNode), currentNode);

            // MAYBE add an index argument instead of creating a sublist

            final List<Step<?>> nextSteps = steps.subList(1, size);

            final int stop = nextNodes.size();

            for (int i = 0; i < stop; i++) {

                final T finalNode = this.selectSingleNode(nextNodes.get(i), nextSteps);

                if (finalNode != null)

                    return finalNode;

            }

            return null;

        } else {

            return CollectionUtils.getFirst(this.lastItem.nextNodes(Node.get(currentNode), currentNode));

        }

    }

    public final List<T> selectNodes(final Object n) {

        return this.selectNodes(Collections.singletonList(n));

    }

    public final List<T> selectNodes(final List<?> nodes) {

        List<?> currentNodes = nodes;

        final int stop = this.items.size();

        for (int i = 0; i < stop; i++) {

            final Step<?> currentStep = this.items.get(i);

            final List<?> nextNodes = currentStep.nextNodes(currentNodes);

            if (nextNodes.isEmpty())

                return Collections.emptyList();

            else

                currentNodes = nextNodes;

        }

        return this.lastItem.nextNodes(currentNodes);

    }

    // encapsulate differences about JDOM nodes

    static abstract class Node<T> {

        static final Node<Element> elem = new ElementNode();

        static final Node<Attribute> attr = new AttributeNode();

        @SuppressWarnings("unchecked")

        public static <TT> Node<TT> get(TT o) {

            if (o instanceof Attribute)

                return (Node<TT>) attr;

            else if (o instanceof Element)

                return (Node<TT>) elem;

            else

                throw new IllegalArgumentException("unknown Node: " + o);

        }

        @SuppressWarnings("unchecked")

        public static <TT> Node<TT> get(Class<TT> clazz) {

            if (clazz == Attribute.class)

                return (Node<TT>) attr;

            else if (clazz == Element.class)

                return (Node<TT>) elem;

            else

                throw new IllegalArgumentException("unknown Node: " + clazz);

        }

        public abstract <S> void nextNodes(final List<S> res, final T node, final Step<S> step);

        // viva jdom who doesn't have a common interface for getName() and getNS()

        abstract T filter(final T elem, final String name, final String ns);

        @Override

        public final String toString() {

            return this.getClass().getSimpleName();

        }

    }

    static class AttributeNode extends Node<Attribute> {

        @Override

        public <S> void nextNodes(final List<S> res, final Attribute node, final Step<S> step) {

            if (step.getAxis() == Axis.ancestor) {

                step.add(node.getParent(), res);

            } else

                throw new IllegalArgumentException(this + " cannot take the passed step: " + step);

        }

        @Override

        Attribute filter(Attribute elem, String name, String ns) {

            if (elem == null)

                return null;

            if (name != null && !name.equals(elem.getName()))

                return null;

            if (ns != null && !ns.equals(elem.getNamespacePrefix()))

                return null;

            return elem;

        }

    }

    static class ElementNode extends Node<Element> {

        @SuppressWarnings("unchecked")

        @Override

        public <S> void nextNodes(final List<S> res, final Element node, final Step<S> step) {

            final Axis axis = step.getAxis();

            if (axis == Axis.ancestor) {

                step.add(node.getParent(), res);

            } else if (axis == Axis.attribute) {

                final List<?> attributes = node.getAttributes();

                final int stop = attributes.size();

                for (int i = 0; i < stop; i++) {

                    step.add(attributes.get(i), res);

                }

            } else if (axis == Axis.child) {

                // jdom : traversal through the List is best done with a Iterator

                for (final Object o : node.getChildren()) {

                    step.add(o, res);

                }

            } else if (axis == Axis.descendantOrSelf) {

                step.add(node, res);

                final Iterator<S> iter = node.getDescendants(new Filter() {

                    @Override

                    public boolean matches(Object obj) {

                        if (!(obj instanceof Element))

                            return false;

                        return step.evaluate(obj) != null;

                    }

                });

                while (iter.hasNext()) {

                    res.add(iter.next());

                }

            } else

                throw new IllegalArgumentException(this + " cannot take the passed step: " + axis);

        }

        @Override

        Element filter(Element elem, String name, String ns) {

            if (elem == null)

                return null;

            if (name != null && !name.equals(elem.getName()))

                return null;

            if (ns != null && !ns.equals(elem.getNamespacePrefix()))

                return null;

            return elem;

        }

    }

}