RandomSec/main/src/com/google/refine/importers/XmlImporter.java

/*

Copyright 2010, Google Inc.
All rights reserved.

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    * Redistributions of source code must retain the above copyright
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    * Redistributions in binary form must reproduce the above
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contributors may be used to endorse or promote products derived from
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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package com.google.refine.importers;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;

import javax.servlet.ServletException;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamConstants;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;

import org.json.JSONArray;
import org.json.JSONObject;

import com.google.refine.ProjectMetadata;
import com.google.refine.importers.tree.ImportColumnGroup;
import com.google.refine.importers.tree.TreeImportingParserBase;
import com.google.refine.importers.tree.TreeReader;
import com.google.refine.importing.ImportingJob;
import com.google.refine.importing.ImportingUtilities;
import com.google.refine.model.Project;
import com.google.refine.util.JSONUtilities;

public class XmlImporter extends TreeImportingParserBase {
    public XmlImporter() {
        super(true);
    }
    
    static private class PreviewParsingState {
        int tokenCount;
    }
    
    final static private int PREVIEW_PARSING_LIMIT = 1000;
    
    @Override
    public JSONObject createParserUIInitializationData(
            ImportingJob job, List<JSONObject> fileRecords, String format) {
        JSONObject options = super.createParserUIInitializationData(job, fileRecords, format);
        try {
            JSONObject firstFileRecord = fileRecords.get(0);
            File file = ImportingUtilities.getFile(job, firstFileRecord);
            InputStream is = new FileInputStream(file);
            try {
                XMLStreamReader parser = createXMLStreamReader(is);
                PreviewParsingState state = new PreviewParsingState();
                
                while (parser.hasNext() && state.tokenCount < PREVIEW_PARSING_LIMIT) {
                    int tokenType = parser.next();
                    state.tokenCount++;
                    if (tokenType == XMLStreamConstants.START_ELEMENT) {
                        JSONObject rootElement = descendElement(parser, state);
                        if (rootElement != null) {
                            JSONUtilities.safePut(options, "dom", rootElement);
                            break;
                        }
                    } else {
                        // ignore everything else
                    }
                }
            } finally {
                is.close();
            }
        } catch (XMLStreamException e) {
            // Ignore
        } catch (IOException e) {
            // Ignore
        }

        return options;
    }
    
    final static private JSONObject descendElement(XMLStreamReader parser, PreviewParsingState state) throws XMLStreamException {
        JSONObject result = new JSONObject();
        {
            String name = parser.getLocalName();
            JSONUtilities.safePut(result, "n", name);
            
            String prefix = parser.getPrefix();
            if (prefix != null) {
                JSONUtilities.safePut(result, "p", prefix);
            }
            String nsUri = parser.getNamespaceURI();
            if (nsUri != null) {
                JSONUtilities.safePut(result, "uri", nsUri);
            }
        }
        
        int namespaceCount = parser.getNamespaceCount();
        if (namespaceCount > 0) {
            JSONArray namespaces = new JSONArray();
            JSONUtilities.safePut(result, "ns", namespaces);
            
            for (int i = 0; i < namespaceCount; i++) {
                JSONObject namespace = new JSONObject();
                JSONUtilities.append(namespaces, namespace);
                JSONUtilities.safePut(namespace, "p", parser.getNamespacePrefix(i));
                JSONUtilities.safePut(namespace, "uri", parser.getNamespaceURI(i));
            }
        }
        
        int attributeCount = parser.getAttributeCount();
        if (attributeCount > 0) {
            JSONArray attributes = new JSONArray();
            JSONUtilities.safePut(result, "a", attributes);
            
            for (int i = 0; i < attributeCount; i++) {
                JSONObject attribute = new JSONObject();
                JSONUtilities.append(attributes, attribute);
                JSONUtilities.safePut(attribute, "n", parser.getAttributeLocalName(i));
                JSONUtilities.safePut(attribute, "v", parser.getAttributeValue(i));
                String prefix = parser.getAttributePrefix(i);
                if (prefix != null) {
                    JSONUtilities.safePut(attribute, "p", prefix);
                }
            }
        }
        
        JSONArray children = new JSONArray();
        while (parser.hasNext() && state.tokenCount < PREVIEW_PARSING_LIMIT) {
            int tokenType = parser.next();
            state.tokenCount++;
            if (tokenType == XMLStreamConstants.END_ELEMENT) {
                break;
            } else if (tokenType == XMLStreamConstants.START_ELEMENT) {
                JSONObject childElement = descendElement(parser, state);
                if (childElement != null) {
                    JSONUtilities.append(children, childElement);
                }
            } else if (tokenType == XMLStreamConstants.CHARACTERS ||
                       tokenType == XMLStreamConstants.CDATA ||
                       tokenType == XMLStreamConstants.SPACE) {
                JSONObject childElement = new JSONObject();
                JSONUtilities.safePut(childElement, "t", parser.getText());
                JSONUtilities.append(children, childElement);
            } else {
                // ignore everything else
            }
        }
        
        if (children.length() > 0) {
            JSONUtilities.safePut(result, "c", children);
        }
        return result;
    }
    
    @Override
    public void parseOneFile(Project project, ProjectMetadata metadata,
            ImportingJob job, String fileSource, InputStream inputStream,
            ImportColumnGroup rootColumnGroup, int limit, JSONObject options,
            List<Exception> exceptions) {
        
        try {
            parseOneFile(project, metadata, job, fileSource,
                new XmlParser(inputStream), rootColumnGroup, limit, options, exceptions);
        } catch (XMLStreamException e) {
            exceptions.add(e);
        }
    }
    
    static public class XmlParser implements TreeReader {
        final protected XMLStreamReader parser;
        
        public XmlParser(InputStream inputStream) throws XMLStreamException {
            parser = createXMLStreamReader(inputStream);
        }
        
        @Override
        public Token next() throws ServletException {
            try {
                if (!parser.hasNext()) {
                    throw new ServletException("End of XML stream");
                }
            } catch (XMLStreamException e) {
                throw new ServletException(e);
            }
            
            int currentToken = -1;
            try {
                currentToken = parser.next();
            } catch (XMLStreamException e) {
                throw new ServletException(e);
            }
            
            return mapToToken(currentToken);
        }
        
        protected Token mapToToken(int token) throws ServletException {
            switch(token){
                case XMLStreamConstants.START_ELEMENT: return Token.StartEntity;
                case XMLStreamConstants.END_ELEMENT: return Token.EndEntity;
                case XMLStreamConstants.CHARACTERS: return Token.Value;
                case XMLStreamConstants.START_DOCUMENT: return Token.Ignorable;
                case XMLStreamConstants.END_DOCUMENT: return Token.Ignorable;
                case XMLStreamConstants.SPACE: return Token.Value;
                case XMLStreamConstants.PROCESSING_INSTRUCTION: return Token.Ignorable;
                case XMLStreamConstants.NOTATION_DECLARATION: return Token.Ignorable;
                case XMLStreamConstants.NAMESPACE: return Token.Ignorable;
                case XMLStreamConstants.ENTITY_REFERENCE: return Token.Ignorable;
                case XMLStreamConstants.DTD: return Token.Ignorable;
                case XMLStreamConstants.COMMENT: return Token.Ignorable;
                case XMLStreamConstants.CDATA: return Token.Ignorable;
                case XMLStreamConstants.ATTRIBUTE: return Token.Ignorable;
                default:
                    return Token.Ignorable;
            }
        }
        
        @Override
        public Token current() throws ServletException{
            return this.mapToToken(parser.getEventType());
        }
        
        @Override
        public boolean hasNext() throws ServletException{
            try {
                return parser.hasNext();
            } catch (XMLStreamException e) {
                throw new ServletException(e);
            }
        }
        
        @Override
        public String getFieldName() throws ServletException{
            try{
                return parser.getLocalName();
            }catch(IllegalStateException e){
                return null;
            }
        }
        
        @Override
        public String getPrefix(){
            return parser.getPrefix();
        }
        
        @Override
        public String getFieldValue(){
            return parser.getText();
        }
        
        @Override
        public int getAttributeCount(){
            return parser.getAttributeCount();
        }
        
        @Override
        public String getAttributeValue(int index){
            return parser.getAttributeValue(index);
        }
        
        @Override
        public String getAttributePrefix(int index){
            return parser.getAttributePrefix(index);
        }
        
        @Override
        public String getAttributeLocalName(int index){
            return parser.getAttributeLocalName(index);
        }
    }
    
    final static private XMLStreamReader createXMLStreamReader(InputStream inputStream) throws XMLStreamException {
        XMLInputFactory factory = XMLInputFactory.newInstance();
        factory.setProperty(XMLInputFactory.IS_COALESCING, true);
        factory.setProperty(XMLInputFactory.IS_REPLACING_ENTITY_REFERENCES, true);
        
        return factory.createXMLStreamReader(inputStream);
    }
    
}