/*
* Copyright 2005 JBoss Inc
*
* Licensed 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.drools.decisiontable.parser.csv;
import java.util.ArrayList;
import java.util.List;
/**
*
* @author <a href="mailto:michael.neale@gmail.com"> Michael Neale</a> Break up
* a CSV line, with all the normal CSV features.
*/
public class CsvLineParser {
private ICsvParser lineParser;
public CsvLineParser() {
this.lineParser = new CsvParserImpl();
}
/**
* Use the current lineParser implementation to return a CSV line as a List
* of cells. (Strings).
*/
public List<String> parse(final CharSequence line) {
return this.lineParser.parse( line.toString() );
}
/**
* This is insurance incase I need to replace it with more complex Csv
* handlers in the future.
*/
static interface ICsvParser {
public List<String> parse(String line);
}
/**
* Parse comma-separated values (CSV), a common Windows file format. Sample
* input: "LU",86.25,"11/4/1998","2:19PM",+4.0625
* <p>
* Inner logic adapted from a C++ original that was Copyright (C) 1999
* Lucent Technologies Excerpted from 'The Practice of Programming' by Brian
* W. Kernighan and Rob Pike.
* <p>
* Included by permission of the http://tpop.awl.com/ web site, which says:
* "You may use this code for any purpose, as long as you leave the
* copyright notice and book citation attached." I have done so.
*
* @author Brian W. Kernighan and Rob Pike (C++ original)
* @author Ian F. Darwin (translation into Java and removal of I/O)
* @author Ben Ballard (rewrote advQuoted to handle '""' and for
* readability)
*/
static class CsvParserImpl
implements
ICsvParser {
public static final char DEFAULT_SEP = ',';
/** Construct a CSV parser, with the default separator (','). */
public CsvParserImpl() {
this( CsvParserImpl.DEFAULT_SEP );
}
/**
* Construct a CSV parser with a given separator.
*
* @param sep
* The single char for the separator (not a list of separator
* characters)
*/
public CsvParserImpl(final char sep) {
this.fieldSep = sep;
}
/** The fields in the current String */
protected List<String> list = new ArrayList<String>();
/** the separator char for this parser */
protected char fieldSep;
/**
* parse: break the input String into fields
*
* @return java.util.Iterator containing each field from the original as
* a String, in order.
*/
public List<String> parse(final String line) {
final StringBuffer sb = new StringBuffer();
this.list.clear(); // recycle to initial state
int i = 0;
if ( line.length() == 0 ) {
this.list.add( line );
return this.list;
}
do {
sb.setLength( 0 );
if ( i < line.length() && line.charAt( i ) == '"' ) {
i = advQuoted( line,
sb,
++i ); // skip
} else {
i = advPlain( line,
sb,
i );
}
this.list.add( sb.toString() );
i++;
} while ( i < line.length() );
return this.list;
}
/** advQuoted: quoted field; return index of next separator */
protected int advQuoted(final String s,
final StringBuffer sb,
final int i) {
int j;
final int len = s.length();
for ( j = i; j < len; j++ ) {
if ( s.charAt( j ) == '"' && j + 1 < len ) {
if ( s.charAt( j + 1 ) == '"' ) {
j++; // skip escape char
} else if ( s.charAt( j + 1 ) == this.fieldSep ) { // next delimeter
j++; // skip end quotes
break;
}
} else if ( s.charAt( j ) == '"' && j + 1 == len ) { // end quotes at end of line
break; // done
}
sb.append( s.charAt( j ) ); // regular character.
}
return j;
}
/** advPlain: unquoted field; return index of next separator */
protected int advPlain(final String s,
final StringBuffer sb,
final int i) {
int j;
j = s.indexOf( this.fieldSep,
i ); // look for separator
if ( j == -1 ) { // none found
sb.append( s.substring( i ) );
return s.length();
} else {
sb.append( s.substring( i,
j ) );
return j;
}
}
}
}