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Ant example source code file (ReplaceRegExp.java)
This example Ant source code file (ReplaceRegExp.java) is included in the DevDaily.com
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The ReplaceRegExp.java source code
/*
* 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.apache.tools.ant.taskdefs.optional;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.InputStreamReader;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.Reader;
import java.io.Writer;
import java.util.Vector;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.DirectoryScanner;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.types.FileSet;
import org.apache.tools.ant.types.RegularExpression;
import org.apache.tools.ant.types.Substitution;
import org.apache.tools.ant.util.FileUtils;
import org.apache.tools.ant.util.regexp.Regexp;
/**
* Performs regular expression string replacements in a text
* file. The input file(s) must be able to be properly processed by
* a Reader instance. That is, they must be text only, no binary.
*
* The syntax of the regular expression depends on the implementation that
* you choose to use. The system property <code>ant.regexp.regexpimpl
* will be the classname of the implementation that will be used (the default
* is <code>org.apache.tools.ant.util.regexp.JakartaOroRegexp and
* requires the Jakarta Oro Package).
*
* <pre>
* For jdk <= 1.3, there are two available implementations:
* org.apache.tools.ant.util.regexp.JakartaOroRegexp (the default)
* Requires the jakarta-oro package
*
* org.apache.tools.ant.util.regexp.JakartaRegexpRegexp
* Requires the jakarta-regexp package
*
* For jdk >= 1.4 an additional implementation is available:
* org.apache.tools.ant.util.regexp.Jdk14RegexpRegexp
* Requires the jdk 1.4 built in regular expression package.
*
* Usage:
*
* Call Syntax:
*
* <replaceregexp file="file"
* match="pattern"
* replace="pattern"
* flags="options"?
* byline="true|false"? >
* regexp?
* substitution?
* fileset*
* </replaceregexp>
*
* NOTE: You must have either the file attribute specified, or at least one fileset subelement
* to operation on. You may not have the file attribute specified if you nest fileset elements
* inside this task. Also, you cannot specify both match and a regular expression subelement at
* the same time, nor can you specify the replace attribute and the substitution subelement at
* the same time.
*
* Attributes:
*
* file --> A single file to operation on (mutually exclusive
* with the fileset subelements)
* match --> The Regular expression to match
* replace --> The Expression replacement string
* flags --> The options to give to the replacement
* g = Substitute all occurrences. default is to replace only the first one
* i = Case insensitive match
*
* byline --> Should this file be processed a single line at a time (default is false)
* "true" indicates to perform replacement on a line by line basis
* "false" indicates to perform replacement on the whole file at once.
*
* Example:
*
* The following call could be used to replace an old property name in a ".properties"
* file with a new name. In the replace attribute, you can refer to any part of the
* match expression in parenthesis using backslash followed by a number like '\1'.
*
* <replaceregexp file="test.properties"
* match="MyProperty=(.*)"
* replace="NewProperty=\1"
* byline="true" />
*
* </pre>
*
*/
public class ReplaceRegExp extends Task {
private File file;
private String flags;
private boolean byline;
private Vector filesets; // Keep jdk 1.1 compliant so others can use this
private RegularExpression regex;
private Substitution subs;
private static final FileUtils FILE_UTILS = FileUtils.getFileUtils();
/**
* Encoding to assume for the files
*/
private String encoding = null;
/** Default Constructor */
public ReplaceRegExp() {
super();
this.file = null;
this.filesets = new Vector();
this.flags = "";
this.byline = false;
this.regex = null;
this.subs = null;
}
/**
* file for which the regular expression should be replaced;
* required unless a nested fileset is supplied.
* @param file The file for which the reg exp should be replaced.
*/
public void setFile(File file) {
this.file = file;
}
/**
* the regular expression pattern to match in the file(s);
* required if no nested <regexp> is used
* @param match the match attribute.
*/
public void setMatch(String match) {
if (regex != null) {
throw new BuildException("Only one regular expression is allowed");
}
regex = new RegularExpression();
regex.setPattern(match);
}
/**
* The substitution pattern to place in the file(s) in place
* of the regular expression.
* Required if no nested <substitution> is used
* @param replace the replace attribute
*/
public void setReplace(String replace) {
if (subs != null) {
throw new BuildException("Only one substitution expression is "
+ "allowed");
}
subs = new Substitution();
subs.setExpression(replace);
}
/**
* The flags to use when matching the regular expression. For more
* information, consult the Perl5 syntax.
* <ul>
* <li>g : Global replacement. Replace all occurrences found
* <li>i : Case Insensitive. Do not consider case in the match
* <li>m : Multiline. Treat the string as multiple lines of input,
* using "^" and "$" as the start or end of any line, respectively,
* rather than start or end of string.
* <li> s : Singleline. Treat the string as a single line of input, using
* "." to match any character, including a newline, which normally,
* it would not match.
*</ul>
* @param flags the flags attribute
*/
public void setFlags(String flags) {
this.flags = flags;
}
/**
* Process the file(s) one line at a time, executing the replacement
* on one line at a time. This is useful if you
* want to only replace the first occurrence of a regular expression on
* each line, which is not easy to do when processing the file as a whole.
* Defaults to <i>false. |
* @param byline the byline attribute as a string
* @deprecated since 1.6.x.
* Use setByLine(boolean).
*/
public void setByLine(String byline) {
Boolean res = Boolean.valueOf(byline);
if (res == null) {
res = Boolean.FALSE;
}
this.byline = res.booleanValue();
}
/**
* Process the file(s) one line at a time, executing the replacement
* on one line at a time. This is useful if you
* want to only replace the first occurrence of a regular expression on
* each line, which is not easy to do when processing the file as a whole.
* Defaults to <i>false.
* @param byline the byline attribute
*/
public void setByLine(boolean byline) {
this.byline = byline;
}
/**
* Specifies the encoding Ant expects the files to be in -
* defaults to the platforms default encoding.
* @param encoding the encoding attribute
*
* @since Ant 1.6
*/
public void setEncoding(String encoding) {
this.encoding = encoding;
}
/**
* list files to apply the replacement to
* @param set the fileset element
*/
public void addFileset(FileSet set) {
filesets.addElement(set);
}
/**
* A regular expression.
* You can use this element to refer to a previously
* defined regular expression datatype instance
* @return the regular expression object to be configured as an element
*/
public RegularExpression createRegexp() {
if (regex != null) {
throw new BuildException("Only one regular expression is allowed.");
}
regex = new RegularExpression();
return regex;
}
/**
* A substitution pattern. You can use this element to refer to a previously
* defined substitution pattern datatype instance.
* @return the substitution pattern object to be configured as an element
*/
public Substitution createSubstitution() {
if (subs != null) {
throw new BuildException("Only one substitution expression is "
+ "allowed");
}
subs = new Substitution();
return subs;
}
/**
* Invoke a regular expression (r) on a string (input) using
* substitutions (s) for a matching regex.
*
* @param r a regular expression
* @param s a Substitution
* @param input the string to do the replacement on
* @param options The options for the regular expression
* @return the replacement result
*/
protected String doReplace(RegularExpression r,
Substitution s,
String input,
int options) {
String res = input;
Regexp regexp = r.getRegexp(getProject());
if (regexp.matches(input, options)) {
log("Found match; substituting", Project.MSG_DEBUG);
res = regexp.substitute(input, s.getExpression(getProject()),
options);
}
return res;
}
/**
* Perform the replacement on a file
*
* @param f the file to perform the relacement on
* @param options the regular expressions options
* @exception IOException if an error occurs
*/
protected void doReplace(File f, int options)
throws IOException {
File temp = FILE_UTILS.createTempFile("replace", ".txt", null);
temp.deleteOnExit();
Reader r = null;
Writer w = null;
try {
if (encoding == null) {
r = new FileReader(f);
w = new FileWriter(temp);
} else {
r = new InputStreamReader(new FileInputStream(f), encoding);
w = new OutputStreamWriter(new FileOutputStream(temp),
encoding);
}
BufferedReader br = new BufferedReader(r);
BufferedWriter bw = new BufferedWriter(w);
PrintWriter pw = new PrintWriter(bw);
boolean changes = false;
log("Replacing pattern '" + regex.getPattern(getProject())
+ "' with '" + subs.getExpression(getProject())
+ "' in '" + f.getPath() + "'" + (byline ? " by line" : "")
+ (flags.length() > 0 ? " with flags: '" + flags + "'" : "")
+ ".", Project.MSG_VERBOSE);
if (byline) {
StringBuffer linebuf = new StringBuffer();
String line = null;
String res = null;
int c;
boolean hasCR = false;
do {
c = br.read();
if (c == '\r') {
if (hasCR) {
// second CR -> EOL + possibly empty line
line = linebuf.toString();
res = doReplace(regex, subs, line, options);
if (!res.equals(line)) {
changes = true;
}
pw.print(res);
pw.print('\r');
linebuf = new StringBuffer();
// hasCR is still true (for the second one)
} else {
// first CR in this line
hasCR = true;
}
} else if (c == '\n') {
// LF -> EOL
line = linebuf.toString();
res = doReplace(regex, subs, line, options);
if (!res.equals(line)) {
changes = true;
}
pw.print(res);
if (hasCR) {
pw.print('\r');
hasCR = false;
}
pw.print('\n');
linebuf = new StringBuffer();
} else { // any other char
if ((hasCR) || (c < 0)) {
// Mac-style linebreak or EOF (or both)
line = linebuf.toString();
res = doReplace(regex, subs, line, options);
if (!res.equals(line)) {
changes = true;
}
pw.print(res);
if (hasCR) {
pw.print('\r');
hasCR = false;
}
linebuf = new StringBuffer();
}
if (c >= 0) {
linebuf.append((char) c);
}
}
} while (c >= 0);
pw.flush();
} else {
String buf = FileUtils.readFully(br);
if (buf == null) {
buf = "";
}
String res = doReplace(regex, subs, buf, options);
if (!res.equals(buf)) {
changes = true;
}
pw.print(res);
pw.flush();
}
r.close();
r = null;
w.close();
w = null;
if (changes) {
log("File has changed; saving the updated file", Project.MSG_VERBOSE);
try {
FILE_UTILS.rename(temp, f);
temp = null;
} catch (IOException e) {
throw new BuildException("Couldn't rename temporary file "
+ temp, getLocation());
}
} else {
log("No change made", Project.MSG_DEBUG);
}
} finally {
FileUtils.close(r);
FileUtils.close(w);
if (temp != null) {
temp.delete();
}
}
}
/**
* Execute the task
*
* @throws BuildException is there is a problem in the task execution.
*/
public void execute() throws BuildException {
if (regex == null) {
throw new BuildException("No expression to match.");
}
if (subs == null) {
throw new BuildException("Nothing to replace expression with.");
}
if (file != null && filesets.size() > 0) {
throw new BuildException("You cannot supply the 'file' attribute "
+ "and filesets at the same time.");
}
int options = 0;
if (flags.indexOf('g') != -1) {
options |= Regexp.REPLACE_ALL;
}
if (flags.indexOf('i') != -1) {
options |= Regexp.MATCH_CASE_INSENSITIVE;
}
if (flags.indexOf('m') != -1) {
options |= Regexp.MATCH_MULTILINE;
}
if (flags.indexOf('s') != -1) {
options |= Regexp.MATCH_SINGLELINE;
}
if (file != null && file.exists()) {
try {
doReplace(file, options);
} catch (IOException e) {
log("An error occurred processing file: '"
+ file.getAbsolutePath() + "': " + e.toString(),
Project.MSG_ERR);
}
} else if (file != null) {
log("The following file is missing: '"
+ file.getAbsolutePath() + "'", Project.MSG_ERR);
}
int sz = filesets.size();
for (int i = 0; i < sz; i++) {
FileSet fs = (FileSet) (filesets.elementAt(i));
DirectoryScanner ds = fs.getDirectoryScanner(getProject());
String[] files = ds.getIncludedFiles();
for (int j = 0; j < files.length; j++) {
File f = new File(fs.getDir(getProject()), files[j]);
if (f.exists()) {
try {
doReplace(f, options);
} catch (Exception e) {
log("An error occurred processing file: '"
+ f.getAbsolutePath() + "': " + e.toString(),
Project.MSG_ERR);
}
} else {
log("The following file is missing: '"
+ f.getAbsolutePath() + "'", Project.MSG_ERR);
}
}
}
}
}
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