Java tutorial
/* * Copyright (c) 2014 Data Harmonisation Panel * * All rights reserved. This program and the accompanying materials are made * available under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation, either version 3 of the License, * or (at your option) any later version. * * You should have received a copy of the GNU Lesser General Public License * along with this distribution. If not, see <http://www.gnu.org/licenses/>. * * Contributors: * Data Harmonisation Panel <http://www.dhpanel.eu> */ package eu.esdihumboldt.hale.io.csv.writer.internal; import java.io.BufferedReader; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStreamReader; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.io.PrintWriter; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.NoSuchElementException; import javax.xml.namespace.QName; import org.apache.commons.io.FileUtils; import au.com.bytecode.opencsv.CSVWriter; import com.google.common.io.Files; import eu.esdihumboldt.hale.common.core.io.IOProviderConfigurationException; import eu.esdihumboldt.hale.common.core.io.ProgressIndicator; import eu.esdihumboldt.hale.common.core.io.report.IOReport; import eu.esdihumboldt.hale.common.core.io.report.IOReporter; import eu.esdihumboldt.hale.common.core.io.report.impl.IOMessageImpl; import eu.esdihumboldt.hale.common.instance.model.Instance; import eu.esdihumboldt.hale.common.instance.model.InstanceCollection; import eu.esdihumboldt.hale.common.schema.model.TypeDefinition; import eu.esdihumboldt.hale.io.csv.InstanceTableIOConstants; import eu.esdihumboldt.hale.io.csv.reader.internal.CSVUtil; import eu.esdihumboldt.hale.io.csv.writer.AbstractTableInstanceWriter; /** * Provider for exporting instances as csv files * * @author Patrick Lieb */ public class CSVInstanceWriter extends AbstractTableInstanceWriter { private char sep; private char quote; private char esc; /** * @see eu.esdihumboldt.hale.common.core.io.IOProvider#isCancelable() */ @Override public boolean isCancelable() { return false; } /** * @see eu.esdihumboldt.hale.common.core.io.impl.AbstractIOProvider#execute(eu.esdihumboldt.hale.common.core.io.ProgressIndicator, * eu.esdihumboldt.hale.common.core.io.report.IOReporter) */ @Override protected IOReport execute(ProgressIndicator progress, IOReporter reporter) throws IOProviderConfigurationException, IOException { boolean solveNestedProperties = getParameter(InstanceTableIOConstants.SOLVE_NESTED_PROPERTIES) .as(Boolean.class, false); // XXX what does "solve nested properties" mean? // get separation, quote and escape sign sep = CSVUtil.getSep(this); quote = CSVUtil.getQuote(this); esc = CSVUtil.getEscape(this); List<String> headerRow = new ArrayList<String>(); // get the parameter to get the type definition String exportType = getParameter(InstanceTableIOConstants.EXPORT_TYPE).as(String.class); QName selectedTypeName = null; if (exportType != null && !exportType.equals("") && !exportType.equals(" ")) { selectedTypeName = QName.valueOf(exportType); } // get all instances of the selected Type InstanceCollection instances = getInstanceCollection(selectedTypeName); Iterator<Instance> instanceIterator = instances.iterator(); Instance instance = null; try { instance = instanceIterator.next(); } catch (NoSuchElementException e) { reporter.error(new IOMessageImpl("There are no instances for the selected type.", e)); return reporter; } // get definition of current instance (only this properties with this // definition type will be written to csv file) TypeDefinition definition = instance.getDefinition(); // first csv file doesn't have a header row, so it' necessary to write // it to a temp directory File tempDir = Files.createTempDir(); File tempFile = new File(tempDir, "tempInstances.csv"); // write instances to csv file (without header) CSVWriter writer = new CSVWriter(new OutputStreamWriter(new FileOutputStream(tempFile)), sep, quote, esc); writeLine(solveNestedProperties, headerRow, instance, writer); while (instanceIterator.hasNext()) { Instance nextInst = instanceIterator.next(); if (nextInst.getDefinition().equals(definition)) { writeLine(solveNestedProperties, headerRow, nextInst, writer); } } writer.close(); // header is only finished if all properties have been processed // insert header to temp file and write it to output insertHeader(tempFile, getTarget().getOutput(), headerRow); FileUtils.deleteDirectory(tempDir); reporter.setSuccess(true); return reporter; } @Override public boolean isPassthrough() { return true; } // write current instance to csv file private void writeLine(boolean solveNestedProperties, List<String> headerRow, Instance instance, CSVWriter writer) { List<String> line = new ArrayList<String>(); Map<String, Object> row = super.getPropertyMap(instance, headerRow, solveNestedProperties); for (String key : headerRow) { Object entry = row.get(key); line.add(getValueOfProperty(entry)); } writer.writeNext(line.toArray(new String[line.size()])); } /** * @see eu.esdihumboldt.hale.common.core.io.impl.AbstractIOProvider#getDefaultTypeName() */ @Override protected String getDefaultTypeName() { return "csv file"; } // insert header into csv file (at beginning of file) private void insertHeader(File source, OutputStream dest, List<String> header) throws IOException { String line = ""; FileInputStream fis = new FileInputStream(source); BufferedReader in = new BufferedReader(new InputStreamReader(fis)); PrintWriter out = new PrintWriter(dest); for (String entry : header) { line += entry; line += sep; } // remove last separator line = line.substring(0, line.lastIndexOf(sep)); out.println(line); String thisLine = ""; while ((thisLine = in.readLine()) != null) { out.println(thisLine); } out.flush(); out.close(); in.close(); source.delete(); } private String getValueOfProperty(Object property) { if (property == null) { return ""; } else { if (property instanceof Instance) { Object instValue = ((Instance) property).getValue(); if (instValue != null) { return (instValue.toString()); } } return property.toString(); } } }