001: /*
002: * $Id: grep.java,v 1.7 2003/11/07 20:16:23 dfs Exp $
003: *
004: * ====================================================================
005: * The Apache Software License, Version 1.1
006: *
007: * Copyright (c) 2000 The Apache Software Foundation. All rights
008: * reserved.
009: *
010: * Redistribution and use in source and binary forms, with or without
011: * modification, are permitted provided that the following conditions
012: * are met:
013: *
014: * 1. Redistributions of source code must retain the above copyright
015: * notice, this list of conditions and the following disclaimer.
016: *
017: * 2. Redistributions in binary form must reproduce the above copyright
018: * notice, this list of conditions and the following disclaimer in
019: * the documentation and/or other materials provided with the
020: * distribution.
021: *
022: * 3. The end-user documentation included with the redistribution,
023: * if any, must include the following acknowledgment:
024: * "This product includes software developed by the
025: * Apache Software Foundation (http://www.apache.org/)."
026: * Alternately, this acknowledgment may appear in the software itself,
027: * if and wherever such third-party acknowledgments normally appear.
028: *
029: * 4. The names "Apache" and "Apache Software Foundation", "Jakarta-Oro"
030: * must not be used to endorse or promote products derived from this
031: * software without prior written permission. For written
032: * permission, please contact apache@apache.org.
033: *
034: * 5. Products derived from this software may not be called "Apache"
035: * or "Jakarta-Oro", nor may "Apache" or "Jakarta-Oro" appear in their
036: * name, without prior written permission of the Apache Software Foundation.
037: *
038: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
039: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
040: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
041: * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
042: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
043: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
044: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
045: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
046: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
047: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
048: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
049: * SUCH DAMAGE.
050: * ====================================================================
051: *
052: * This software consists of voluntary contributions made by many
053: * individuals on behalf of the Apache Software Foundation. For more
054: * information on the Apache Software Foundation, please see
055: * <http://www.apache.org/>.
056: */
057:
058: package examples;
059:
060: import java.io.*;
061: import java.util.*;
062:
063: import org.apache.oro.text.*;
064: import org.apache.oro.text.regex.*;
065:
066: /**
067: * This is a no-frills implementation of grep using Perl regular expressions.
068: * You can easily add most of the options present in most grep versions by
069: * creating a MatchAction class or classes whose behavior varies based on
070: * the provided flags.
071: *
072: * @version @version@
073: */
074: public final class grep {
075: static int _file = 0;
076:
077: // args[] is declared final so that Inner Class may reference it.
078: public static final void main(final String[] args) {
079: MatchActionProcessor processor = new MatchActionProcessor();
080:
081: if (args.length < 2) {
082: System.err.println("Usage: grep <pattern> <filename>");
083: System.exit(1);
084: }
085:
086: try {
087: if (args.length > 2) {
088: // Print filename before line if more than one file is specified.
089: // Rely on _file to point to current file being processed.
090: processor.addAction(args[0], new MatchAction() {
091: public void processMatch(MatchActionInfo info) {
092: info.output.println(args[_file] + ":"
093: + info.line);
094: }
095: });
096: } else {
097: // We rely on the default action of printing matched
098: // lines to the given OutputStream
099: processor.addAction(args[0]);
100: }
101: } catch (MalformedPatternException e) {
102: System.err.println("Bad pattern.");
103: e.printStackTrace();
104: System.exit(1);
105: }
106:
107: for (_file = 1; _file < args.length; _file++) {
108: try {
109: processor.processMatches(new FileInputStream(
110: args[_file]), System.out);
111: } catch (IOException e) {
112: System.err.println("Error opening or reading "
113: + args[_file]);
114: e.printStackTrace();
115: System.exit(1);
116: }
117: }
118: }
119:
120: }
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