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* Licensed to the Apache Software Foundation (ASF) under one
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* or more contributor license agreements. See the NOTICE file
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* distributed with this work for additional information
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* regarding copyright ownership. The ASF licenses this file
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* to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing,
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* software distributed under the License is distributed on an
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* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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* KIND, either express or implied. See the License for the
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* specific language governing permissions and limitations
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package org.apache.commons.csv.writer;
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import java.io.BufferedReader;
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import java.io.InputStream;
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import java.io.InputStreamReader;
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* Tries to guess a config based on an InputStream.
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* @author Martin van den Bemt
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public class CSVConfigGuesser {
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/** The stream to read */
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private InputStream in;
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* if the file has a field header (need this info, to be able to guess better)
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private boolean hasFieldHeader = false;
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/** The found config */
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protected CSVConfig config;
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public CSVConfigGuesser() {
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this.config = new CSVConfig();
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* @param in the inputstream to guess from
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public CSVConfigGuesser(InputStream in) {
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public void setInputStream(InputStream in) {
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* @return the inputstream that was set.
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protected InputStream getInputStream() {
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* Guess the config based on the first 10 (or less when less available)
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* records of a CSV file.
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* @return the guessed config.
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public CSVConfig guess() {
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BufferedReader bIn = new BufferedReader(new InputStreamReader((getInputStream())));
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String[] lines = new String[10];
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while ( (line = bIn.readLine()) != null && counter <= 10) {
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lines[counter] = line;
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// remove nulls from the array, so we can skip the null checking.
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String[] newLines = new String[counter];
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System.arraycopy(lines, 0, newLines, 0, counter);
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} catch(Exception e) {
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} catch(Exception e) {
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CSVConfig conf = config;
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// cleanup the config.
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protected void analyseLines(String[] lines) {
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guessFixedWidth(lines);
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guessFieldSeperator(lines);
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* Guess if this file is fixedwidth.
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* Just basing the fact on all lines being of the same length
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protected void guessFixedWidth(String[] lines) {
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// assume fixedlength.
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config.setFixedWidth(true);
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for (int i = 0; i < lines.length; i++) {
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lastLength = lines[i].length();
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if (lastLength != lines[i].length()) {
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config.setFixedWidth(false);
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protected void guessFieldSeperator(String[] lines) {
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if (config.isFixedWidth()) {
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guessFixedWidthSeperator(lines);
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for (int i = 0; i < lines.length; i++) {
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protected void guessFixedWidthSeperator(String[] lines) {
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// keep track of the fieldlength
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int previousMatch = -1;
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for (int i = 0; i < lines[0].length(); i++) {
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boolean charMatches = true;
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for (int j = 0; j < lines.length; j++) {
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last = lines[j].charAt(i);
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if (last != lines[j].charAt(i)) {
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if (previousMatch == -1) {
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CSVField field = new CSVField();
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field.setName("field"+config.getFields().length+1);
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field.setSize((i-previousMatch));
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config.addField(field);
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* @return if the field uses a field header. Defaults to false.
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public boolean hasFieldHeader() {
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return hasFieldHeader;
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* Specify if the CSV file has a field header
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* @param hasFieldHeader true or false
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public void setHasFieldHeader(boolean hasFieldHeader) {
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this.hasFieldHeader = hasFieldHeader;
added
removed
src/java/org/apache/commons/csv/writer/CSVConfigGuesser.java
