ImportingParserBase.java

/*

Copyright 2011, Google Inc.
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    * Redistributions in binary form must reproduce the above
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*/

package com.google.refine.importers;

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

import org.apache.commons.lang.NotImplementedException;
import org.json.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.refine.ProjectMetadata;
import com.google.refine.importers.ImporterUtilities.MultiFileReadingProgress;
import com.google.refine.importing.ImportingJob;
import com.google.refine.importing.ImportingParser;
import com.google.refine.importing.ImportingUtilities;
import com.google.refine.model.Column;
import com.google.refine.model.ModelException;
import com.google.refine.model.Project;
import com.google.refine.util.JSONUtilities;

abstract public class ImportingParserBase implements ImportingParser {
    final static Logger logger = LoggerFactory.getLogger("ImportingParserBase");

    final protected boolean useInputStream;
    
    /**
     * @param useInputStream true if parser takes an InputStream, false if it takes a Reader.
     */
    protected ImportingParserBase(boolean useInputStream) {
        this.useInputStream = useInputStream;
    }
    
    @Override
    public JSONObject createParserUIInitializationData(ImportingJob job,
            List<JSONObject> fileRecords, String format) {
        JSONObject options = new JSONObject();
        JSONUtilities.safePut(options, "includeFileSources", fileRecords.size() > 1);
        
        return options;
    }
    
    @Override
    public void parse(Project project, ProjectMetadata metadata,
            final ImportingJob job, List<JSONObject> fileRecords, String format,
            int limit, JSONObject options, List<Exception> exceptions) {
        MultiFileReadingProgress progress = ImporterUtilities.createMultiFileReadingProgress(job, fileRecords);
        for (JSONObject fileRecord : fileRecords) {
            if (job.canceled) {
                break;
            }
            
            try {
                parseOneFile(project, metadata, job, fileRecord, limit, options, exceptions, progress);
            } catch (IOException e) {
                exceptions.add(e);
            }
            
            if (limit > 0 && project.rows.size() >= limit) {
                break;
            }
        }
    }
    
    public void parseOneFile(
        Project project,
        ProjectMetadata metadata,
        ImportingJob job,
        JSONObject fileRecord,
        int limit,
        JSONObject options,
        List<Exception> exceptions,
        final MultiFileReadingProgress progress
    ) throws IOException {
        final File file = ImportingUtilities.getFile(job, fileRecord);
        final String fileSource = ImportingUtilities.getFileSource(fileRecord);
        
        progress.startFile(fileSource);
        try {
            InputStream inputStream = ImporterUtilities.openAndTrackFile(fileSource, file, progress);
            try {
                if (useInputStream) {
                    parseOneFile(project, metadata, job, fileSource, inputStream, limit, options, exceptions);
                } else {
                    String commonEncoding = JSONUtilities.getString(options, "encoding", null);
                    if (commonEncoding != null && commonEncoding.isEmpty()) {
                        commonEncoding = null;
                    }
                    
                    Reader reader = ImportingUtilities.getReaderFromStream(
                        inputStream, fileRecord, commonEncoding);
                    
                    parseOneFile(project, metadata, job, fileSource, reader, limit, options, exceptions);
                }
            } finally {
                inputStream.close();
            }
        } finally {
            progress.endFile(fileSource, file.length());
        }
    }
    
    public void parseOneFile(
        Project project,
        ProjectMetadata metadata,
        ImportingJob job,
        String fileSource,
        Reader reader,
        int limit,
        JSONObject options,
        List<Exception> exceptions
    ) {
        throw new NotImplementedException();
    }
    
    public void parseOneFile(
        Project project,
        ProjectMetadata metadata,
        ImportingJob job,
        String fileSource,
        InputStream inputStream,
        int limit,
        JSONObject options,
        List<Exception> exceptions
    ) {
        throw new NotImplementedException();
    }
    
    
    protected static int addFilenameColumn(Project project) {
        String fileNameColumnName = "File";
        if (project.columnModel.getColumnByName(fileNameColumnName) == null) {
            try {
                project.columnModel.addColumn(
                    0, new Column(project.columnModel.allocateNewCellIndex(), fileNameColumnName), false);

                return 0;
            } catch (ModelException e) {
                // Shouldn't happen: We already checked for duplicate name.
                logger.error("ModelException adding Filename column",e);
            }
            return -1;
        } else {
            return 0;
        }
    }

}