com.dulion.astatium.mesh.shredder.XmlShredder.java Source code

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Here is the source code for com.dulion.astatium.mesh.shredder.XmlShredder.java

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/**
 * Copyright 2016 Phillip DuLion
 *
 * 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 com.dulion.astatium.mesh.shredder;

import com.dulion.astatium.mesh.Context;
import com.dulion.astatium.mesh.DataGraph;
import com.dulion.astatium.mesh.DataNode;
import com.dulion.astatium.mesh.MetaGraph;
import com.dulion.astatium.mesh.Shredder;

import org.apache.commons.lang3.StringUtils;

import java.io.InputStream;
import java.io.Reader;
import java.util.ArrayList;
import java.util.List;

import javax.xml.namespace.QName;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.events.XMLEvent;

public class XmlShredder implements Shredder {

    private final ContextManager manager;

    private final ThreadLocal<XMLInputFactory> factory;

    public XmlShredder(MetaGraph metaGraph) {
        this.manager = (ContextManager) metaGraph;
        this.factory = ThreadLocal.withInitial(() -> {
            XMLInputFactory factory = XMLInputFactory.newInstance();
            factory.setProperty(XMLInputFactory.IS_NAMESPACE_AWARE, Boolean.TRUE);
            factory.setProperty(XMLInputFactory.IS_COALESCING, Boolean.TRUE);
            factory.setProperty(XMLInputFactory.IS_REPLACING_ENTITY_REFERENCES, Boolean.TRUE);
            return factory;
        });
    }

    @Override
    public DataGraph shred(InputStream in) throws XMLStreamException {
        return shred(factory.get().createXMLStreamReader(in));
    }

    @Override
    public DataGraph shred(Reader in) throws XMLStreamException {
        return shred(factory.get().createXMLStreamReader(in));
    }

    private DataGraph shred(XMLStreamReader stream) throws XMLStreamException {
        DataNode[] items = new Instance(stream).shred();
        return new DefaultDataGraph(manager, items, 0, items.length);
    }

    private class Instance {
        private final List<DataNode> shreds = new ArrayList<>();

        private final XMLStreamReader stream;

        private int itemId = 0;

        public Instance(XMLStreamReader stream) {
            this.stream = stream;
        }

        public DataNode[] shred() throws XMLStreamException {
            startDocument();

            DataNode[] items = new DataNode[shreds.size()];
            return shreds.toArray(items);
        }

        private void startDocument() throws XMLStreamException {
            while (stream.hasNext()) {
                int eventType = stream.next();
                switch (eventType) {
                case XMLEvent.START_ELEMENT:
                    startElement(manager.getRootContext(), -1);
                    break;

                case XMLEvent.END_DOCUMENT:
                    return;

                default: // ignore
                }
            }
        }

        private int startElement(Context parent, int parentId) throws XMLStreamException {
            Context context = manager.getElementContext(parent, stream.getName());
            DefaultDataNode tag = new DefaultDataNode(context, parentId, itemId++, "");
            shreds.add(tag);

            int size = shredAttributes(tag);
            size += shredElements(tag);
            tag.setSize(size);

            return size + 1;
        }

        private int shredAttributes(DataNode parent) {
            int count = stream.getAttributeCount();
            for (int i = 0; i < count; i++) {
                QName name = stream.getAttributeName(i);
                String text = stream.getAttributeValue(i);

                Context leaf = manager.getAttributeContext(parent.getContext(), name);
                shreds.add(new DefaultDataNode(leaf, parent.getNodeId(), itemId++, text));
            }

            return count;
        }

        private int shredElements(DefaultDataNode parent) throws XMLStreamException {
            int count = 0;
            while (stream.hasNext()) {
                int eventType = stream.next();
                switch (eventType) {
                case XMLEvent.START_ELEMENT:
                    count += startElement(parent.getContext(), parent.getNodeId());
                    break;

                case XMLEvent.CHARACTERS:
                    shredCharacters(parent);
                    break;

                case XMLEvent.END_ELEMENT:
                    return count;

                default: // Ignore
                }
            }
            return count;
        }

        private void shredCharacters(DefaultDataNode parent) throws XMLStreamException {
            String text = stream.getText();
            if (StringUtils.isNotBlank(text)) {
                parent.setText(text);
            }
        }
    }
}