Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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 org.cyclop.service.exporter.intern; import java.io.ByteArrayOutputStream; import java.io.OutputStream; import java.io.PrintWriter; import java.io.UnsupportedEncodingException; import java.util.Iterator; import java.util.List; import java.util.Map; import javax.inject.Inject; import javax.inject.Named; import org.cyclop.common.AppConfig; import org.cyclop.model.CqlColumnValue; import org.cyclop.model.CqlDataType; import org.cyclop.model.CqlExtendedColumnName; import org.cyclop.model.CqlQuery; import org.cyclop.model.CqlQueryResult; import org.cyclop.model.exception.ServiceException; import org.cyclop.service.cassandra.QueryService; import org.cyclop.service.converter.DataConverter; import org.cyclop.service.converter.DataExtractor; import org.cyclop.service.exporter.CsvQueryResultExporter; import org.cyclop.validation.EnableValidation; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.datastax.driver.core.DataType; import com.datastax.driver.core.Row; import com.google.common.collect.ImmutableList; import com.google.common.collect.ImmutableSet; /** @author Maciej Miklas */ @Named @EnableValidation public class CsvQueryResultExporterImpl implements CsvQueryResultExporter { private final static Logger LOG = LoggerFactory.getLogger(CsvQueryResultExporterImpl.class); @Inject private DataExtractor extractor; @Inject private DataConverter converter; @Inject private AppConfig.QueryExport conf; @Inject private QueryService queryService; @Override public String exportAsCsv(CqlQuery query) { ByteArrayOutputStream bos = new ByteArrayOutputStream(); exportAsCsv(query, bos); try { String resStr = new String(bos.toByteArray(), conf.encoding); return resStr; } catch (UnsupportedEncodingException e) { throw new ServiceException( "Encoding: " + conf.encoding + " caused error during export: " + e.getMessage(), e); } } @Override public void exportAsCsv(CqlQuery query, OutputStream output) { LOG.debug("Starting CSV export for {}", query); PrintWriter out = new PrintWriter(output); CqlQueryResult result = queryService.execute(query, false); // header appendHeader(query, out); // column names ImmutableList<CqlExtendedColumnName> columns = result.rowMetadata.columns; appendColumns(out, columns); out.append(conf.separatorRow); // content for (Row row : result) { appendRow(out, row, columns); out.append(conf.separatorRow); } out.flush(); out.close(); } private void appendRow(PrintWriter out, Row row, List<CqlExtendedColumnName> cols) { LOG.debug("Appending next row"); Iterator<CqlExtendedColumnName> it = cols.iterator(); while (it.hasNext()) { CqlExtendedColumnName column = it.next(); CqlDataType dataType = column.dataType; if (dataType.name == DataType.Name.SET || dataType.name == DataType.Name.LIST) { appendCollection(out, row, column); } else if (dataType.name == DataType.Name.MAP) { appendMap(out, row, column); } else { appendSingleValue(out, row, column); } if (it.hasNext()) { out.append(conf.separatorColumn); } } } private void appendMap(PrintWriter out, Row row, CqlExtendedColumnName column) { ImmutableSet<Map.Entry<CqlColumnValue, CqlColumnValue>> displayMap = extractor.extractMap(row, column) .entrySet(); Iterator<Map.Entry<CqlColumnValue, CqlColumnValue>> it = displayMap.iterator(); LOG.trace("Appending: {}", displayMap); StringBuilder mapBuf = new StringBuilder(); while (it.hasNext()) { Map.Entry<CqlColumnValue, CqlColumnValue> entry = it.next(); CqlColumnValue key = entry.getKey(); String keyText = esc(converter.convert(key.value)); mapBuf.append(keyText); mapBuf.append(conf.separatorMap); CqlColumnValue val = entry.getValue(); String valText = esc(converter.convert(val.value)); mapBuf.append(valText); if (it.hasNext()) { mapBuf.append(conf.separatorList); } } String mapVal = esc(mapBuf.toString()); LOG.trace("Appended map: {}", mapVal); out.append(mapVal); } private void appendCollection(PrintWriter out, Row row, CqlExtendedColumnName column) { ImmutableList<CqlColumnValue> content = extractor.extractCollection(row, column); LOG.trace("Appending {}", content); Iterator<CqlColumnValue> contentIt = content.iterator(); StringBuilder listBuild = new StringBuilder(); while (contentIt.hasNext()) { CqlColumnValue cqlColumnValue = contentIt.next(); String valText = esc(converter.convert(cqlColumnValue.value)); listBuild.append(valText); if (contentIt.hasNext()) { listBuild.append(conf.separatorList); } } String colVal = esc(listBuild.toString()); LOG.trace("Append collection: {}", colVal); out.append(colVal); } private void appendSingleValue(PrintWriter out, Row row, CqlExtendedColumnName column) { CqlColumnValue cqlColumnValue = extractor.extractSingleValue(row, column); String valText = esc(converter.convert(cqlColumnValue.value)); LOG.trace("Append single value: {}", valText); out.append(valText); } private void appendHeader(CqlQuery query, PrintWriter out) { String headerVal = prep(query.part); LOG.trace("Append header: {}", headerVal); out.append(headerVal); out.append(conf.separatorQuery); } private void appendColumns(PrintWriter out, List<CqlExtendedColumnName> columns) { if (columns.isEmpty()) { return; } LOG.trace("Appending {}", columns); Iterator<CqlExtendedColumnName> commonColsIt = columns.iterator(); while (commonColsIt.hasNext()) { CqlExtendedColumnName next = commonColsIt.next(); out.append(prep(esc(next.toDisplayString()))); if (commonColsIt.hasNext()) { out.append(conf.separatorColumn); } } } private String prep(String val) { if (val == null) { val = ""; } if (conf.trim) { val = val.trim(); } if (conf.removeCrChars) { val = val.replaceAll("[\n\r]", ""); } return val; } private String esc(String val) { return conf.valueBracketStart + prep(val) + conf.valueBracketEnd; } }