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Regex?

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  Regex? Knute Johnson <eternal@knutejohnson.com> - 2014-06-19 21:39 -0700
    Re: Regex? Knute Johnson <eternal@knutejohnson.com> - 2014-06-19 22:03 -0700
      Re: Regex? Robert Klemme <shortcutter@googlemail.com> - 2014-06-20 09:25 +0200
        Re: Regex? Knute Johnson <eternal@knutejohnson.com> - 2014-06-20 08:06 -0700
          Re: Regex? Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-06-20 11:14 -0400
            Re: Regex? Knute Johnson <eternal@knutejohnson.com> - 2014-06-20 15:46 -0700
              Re: Regex? Roedy Green <see_website@mindprod.com.invalid> - 2014-06-25 08:15 -0700
                Re: Regex? Knute Johnson <eternal@knutejohnson.com> - 2014-06-25 18:10 -0700
                  Re: Regex? Knute Johnson <eternal@knutejohnson.com> - 2014-06-30 09:52 -0700
      Re: Regex? Roedy Green <see_website@mindprod.com.invalid> - 2014-06-21 09:49 -0700
    Re: Regex? Roedy Green <see_website@mindprod.com.invalid> - 2014-08-01 02:45 -0700

#28787 — Regex?

How do you search for a String that contains a character such as ( that 
is special to a regex?

Thanks,

-- 

Knute Johnson

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#28788

Pattern.compile(Pattern.quote("the string with the ) in it"));

I hate that, look for it for an hour, write something here and then come 
across the answer 2 minutes later.

k...

On 6/19/2014 21:39, Knute Johnson wrote:
> How do you search for a String that contains a character such as ( that
> is special to a regex?
>
> Thanks,
>


-- 

Knute Johnson

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#28789

On 06/20/2014 07:03 AM, Knute Johnson wrote:
> Pattern.compile(Pattern.quote("the string with the ) in it"));

There are more ways:

Pattern.compile("the string with the \\) in it");
Pattern.compile("the string with the \\Q)\\E in it");

Cheers

	robert

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#28793

On 6/20/2014 00:25, Robert Klemme wrote:
> On 06/20/2014 07:03 AM, Knute Johnson wrote:
>> Pattern.compile(Pattern.quote("the string with the ) in it"));
>
> There are more ways:
>
> Pattern.compile("the string with the \\) in it");
> Pattern.compile("the string with the \\Q)\\E in it");
>
> Cheers
>
>      robert

Thanks Robert,

The problem was actually

String str = "(something";
Pattern.compile(str);

so now it is

Pattern.compile(Pattern.quote(str));

I hate to make them

Pattern.compile(str+"\\Q")

(the cognoscenti would have my ...)

-- 

Knute Johnson

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#28796

On 6/20/2014 11:06 AM, Knute Johnson wrote:
> On 6/20/2014 00:25, Robert Klemme wrote:
>> On 06/20/2014 07:03 AM, Knute Johnson wrote:
>>> Pattern.compile(Pattern.quote("the string with the ) in it"));
>>
>> There are more ways:
>>
>> Pattern.compile("the string with the \\) in it");
>> Pattern.compile("the string with the \\Q)\\E in it");
>>
>> Cheers
>>
>>      robert
>
> Thanks Robert,
>
> The problem was actually
>
> String str = "(something";
> Pattern.compile(str);
>
> so now it is
>
> Pattern.compile(Pattern.quote(str));
>
> I hate to make them
>
> Pattern.compile(str+"\\Q")
>
> (the cognoscenti would have my ...)

     Something seems peculiar: If the cognoscenti who provide the
search strings want all characters to stand for themselves and
not to function as regex metacharacters, what's the point of
using a regex?  Why not use theString.indexOf(str)?  Is there
more to the use case than we've been told?

-- 
Eric Sosman
esosman@comcast-dot-net.invalid

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#28800

On 6/20/2014 08:14, Eric Sosman wrote:
> On 6/20/2014 11:06 AM, Knute Johnson wrote:
>> On 6/20/2014 00:25, Robert Klemme wrote:
>>> On 06/20/2014 07:03 AM, Knute Johnson wrote:
>>>> Pattern.compile(Pattern.quote("the string with the ) in it"));
>>>
>>> There are more ways:
>>>
>>> Pattern.compile("the string with the \\) in it");
>>> Pattern.compile("the string with the \\Q)\\E in it");
>>>
>>> Cheers
>>>
>>>      robert
>>
>> Thanks Robert,
>>
>> The problem was actually
>>
>> String str = "(something";
>> Pattern.compile(str);
>>
>> so now it is
>>
>> Pattern.compile(Pattern.quote(str));
>>
>> I hate to make them
>>
>> Pattern.compile(str+"\\Q")
>>
>> (the cognoscenti would have my ...)
>
>      Something seems peculiar: If the cognoscenti who provide the
> search strings want all characters to stand for themselves and
> not to function as regex metacharacters, what's the point of
> using a regex?  Why not use theString.indexOf(str)?  Is there
> more to the use case than we've been told?
>

Well I've been round and round on this, I thought originally that I 
could find all the examples of the search string with one call to 
Matcher.matches() but I can't figure out how to do that.  It may be 
possible but I can't find an example and String.indexOf is case 
sensitive and it is very easy to make Matcher.find() not be which is 
what I want for this application.

As to the cognoscenti, I meant using the + operator to concatenate a 
String but if I can work a Vector in there somewhere I will :-).

-- 

Knute Johnson

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#28848

On Fri, 20 Jun 2014 15:46:13 -0700, Knute Johnson
<eternal@knutejohnson.com> wrote, quoted or indirectly quoted someone
who said :

>Well I've been round and round on this, I thought originally that I 
>could find all the examples of the search string with one call to 
>Matcher.matches() but I can't figure out how to do that

I have examples of use of all the regex methods in little SSCCEs.

See http://mindprod.com/jgloss/regex.html
-- 
Roedy Green Canadian Mind Products http://mindprod.com
Why program by hand in 5 days what you can spend
2 to 5 years of your life automating.
~ Terence Parr 1964-08-17

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#28856

On 6/25/2014 08:15, Roedy Green wrote:
> On Fri, 20 Jun 2014 15:46:13 -0700, Knute Johnson
> <eternal@knutejohnson.com> wrote, quoted or indirectly quoted someone
> who said :
>
>> Well I've been round and round on this, I thought originally that I
>> could find all the examples of the search string with one call to
>> Matcher.matches() but I can't figure out how to do that
>
> I have examples of use of all the regex methods in little SSCCEs.
>
> See http://mindprod.com/jgloss/regex.html
>

Thanks I'll take a look.

I think what I thought I could do is not possible.  Apparently you can't 
get multiple capture groups without multiple sets of parenthesis.  I 
thought I could do something like;

Pattern.compile("(the)*") and capture all of the 'the's in the string in 
their own group.  But as it turns out each group must have its own set 
of parenthesis.

So instead of that approach I decided to use Matcher.find() to search 
through the string and keep a list of the matches.

I'll post some code once I've got it cleaned up and debugged.

-- 

Knute Johnson

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#28876

On 6/25/2014 18:10, Knute Johnson wrote:
>
> So instead of that approach I decided to use Matcher.find() to search
> through the string and keep a list of the matches.
>
> I'll post some code once I've got it cleaned up and debugged.
>

The point behind my regex questions were that I was trying to duplicate 
the text search feature found on FireFox.  On FireFox if you type CTRL-F 
you get a text box and some controls on the bottom of the FireFox window 
that you can type into and search the text on the displayed web page. 
For my purposes I don't need the up and down arrows and the Match Case 
features.  I just wanted to find the text and be able to use the ENTER 
and SHIFT-ENTER keys to move about and the ESC key to close the search 
window.

The interesting thing that I found by accident on a web search is that a 
JTextComponent that is not in focus will not display selected text.  I 
still need to come up with a simple reversible way to swap out the Caret 
on the target JTextComponent when my SearchField is displayed.

Code is posted below and if you want to play with it, you can find the 
source and a compiled jar at: http://knutejohnson.com/searchfield.

Thank you everybody that responded to my query.

package com.knutejohnson.components;

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;
import javax.swing.*;

import com.knutejohnson.classes.*;

public class TestSearchField extends JFrame {
     private final JTextArea textArea = new JTextArea(10,40);
     private final SearchField searchField = new SearchField(10,textArea);
     private final JScrollPane scrollPane =
      new JScrollPane(textArea,
      JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
      JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);

     private boolean flag;

     public TestSearchField() {
         try {
             URL url = new URL("http://knutejohnson.com/gba");
             BufferedReader br = new BufferedReader(new InputStreamReader(
              url.openStream()));
             String str;
             while ((str = br.readLine()) != null) {
                 textArea.append(str);
                 textArea.append("\n");
             }
             textArea.setCaretPosition(0);
             br.close();
         } catch (IOException ex) {
             ex.printStackTrace();
         }

         addWindowListener(new WindowAdapter() {
             public void windowClosing(WindowEvent we) {
                 TestSearchField.this.dispose();
             }
         });

         add(scrollPane,BorderLayout.CENTER);

         textArea.addKeyListener(new KeyAdapter() {
             public void keyPressed(KeyEvent ke) {
                 if (ke.isControlDown() && ke.getKeyCode() == 
KeyEvent.VK_F) {
                     if (!flag) {
                         flag = true;
                         TestSearchField.this.add(
                          searchField,BorderLayout.SOUTH);
                         TestSearchField.this.pack();
                     }
                     searchField.requestFocus();
                 }
             }
         });
         textArea.setLineWrap(true);
         textArea.setWrapStyleWord(true);

         searchField.addCloseListener(new CloseListener() {
             public void close(CloseEvent ce) {
                 remove(searchField);
                 pack();
                 flag = false;
             }
         });

         pack();
         setVisible(true);
     }

     public static void main(String[] args) {
         EventQueue.invokeLater(new Runnable() {
             public void run() {
                 new TestSearchField();
             }
         });
     }
}

package com.knutejohnson.components;

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.util.regex.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;

import com.knutejohnson.classes.*;

/**
  * Entering text into the SearchField causes a scan of the JTextComponent
  * parameter.  Matching text will be highlighted and the background color
  * of the SearchField will be used to indicate successful/unsuccesful 
searches
  *
  * @author  Knute Johnson
  */

public class SearchField extends JTextField implements DocumentListener,
  KeyListener {
     /** background color to indicate a successful search */
     private static final Color LIGHT_GREEN = new Color(220,255,220);
     /** background color to indicate an unsuccessful search */
     private static final Color LIGHT_RED = new Color(255,220,220);

     /** the JTextComponent to be searched */
     private final JTextComponent comp;
     /** a list of begin and end locations of matching text */
     private final java.util.List<Point> finds = new ArrayList<>();

     /** the index of the currently highlighted find */
     private int index;

     /**
      * Constructs a SearchField with the specified length and 
JTextComponent
      * to search.
      *
      * @param columns   the number of columns to use to calculate the
      *                  preferred width
      * @param comp      the {@code JTextComponent} to search
      */
     public SearchField(int columns, JTextComponent comp) {
         super(columns);

         this.comp = comp;

         getDocument().addDocumentListener(this);
         addKeyListener(this);

         // give the JTextComponent to be searched a new Caret that has a
         // visible selection even when out of focus
         comp.setCaret(new DefaultCaret() {
             @Override public void setSelectionVisible(boolean visible) {
                 super.setSelectionVisible(true);
             }
         });
     }

     /**
      * Method of the KeyListener interface that is used to detect ENTER,
      * SHIFT+ENTER and the ESC key presses
      *
      * @param ke    the KeyEvent passed by in by the event producer
      */
     @Override public void keyPressed(KeyEvent ke) {
         // if ENTER has been pressed
         if (ke.getKeyCode() == KeyEvent.VK_ENTER) {
             // if there are finds
             if (finds.size() > 0) {
                 if (ke.isShiftDown()) {
                     if (--index < 0)
                         index = finds.size() - 1;
                 } else
                     if (++index >= finds.size())
                         index = 0;

                 // highlight the matching text
                 comp.setCaretPosition(finds.get(index).x);
                 comp.moveCaretPosition(finds.get(index).y);
             }
         }
         // if ESC has been pressed
         if (ke.getKeyCode() == KeyEvent.VK_ESCAPE)
             // send a CloseEvent to all registered CloseListeners
             fireCloseEvent();
     }

     /**
      * Unused method of the KeyListener interface
      */
     @Override public void keyReleased(KeyEvent ke) {
     }

     /**
      * Unused method of the KeyListener interface
      */
     @Override public void keyTyped(KeyEvent ke) {
     }

     /**
      * Calls the search() method when an attribute changed
      */
     @Override public void changedUpdate(DocumentEvent de) {
         search();
     }

     /**
      * Calls the search() method when there was an insert into the document
      */
     @Override public void insertUpdate(DocumentEvent de) {
         search();
     }

     /**
      * Calls the search() method when part of the document was removed
      */
     @Override public void removeUpdate(DocumentEvent de) {
         search();
     }

     /**
      * Method to perform the actual search of the {@code TextComponent}
      */
     private void search() {
         try {
             Document doc = getDocument();
             // if the SearchField document has no text
             //  clear the finds,
             //  set the search index to 0,
             //  color the SearchField white,
             //  remove any highlighted text,
             //  and return
             if (doc.getLength() == 0) {
                 finds.clear();
                 index = 0;
                 setBackground(Color.WHITE);
                 comp.setCaretPosition(comp.getCaretPosition());
                 return;
             }

             // get the search string
             String str = doc.getText(0,doc.getLength());
             // create the Pattern and Matcher
             Pattern p = Pattern.compile(Pattern.quote(str),
              Pattern.CASE_INSENSITIVE);
             Matcher m = p.matcher(comp.getText());
             // clear the finds
             finds.clear();
             // look for and save all found locations of the search string
             while (m.find())
                 finds.add(new Point(m.start(),m.end()));

             // if matches were found
             if (finds.size() > 0) {
                 // set the SearchField background to green and
                 //  mark the first find
                 setBackground(LIGHT_GREEN);
                 comp.setCaretPosition(finds.get(0).x);
                 comp.moveCaretPosition(finds.get(0).y);
                 index = 0;
             // otherwise
             } else {
                 // set the SearchField background to red
                 setBackground(LIGHT_RED);
                 comp.setCaretPosition(comp.getCaretPosition());
             }
         } catch (BadLocationException ble) {
             ble.printStackTrace();
         }
     }

     /** list of CloseListeners */
     private final java.util.List<CloseListener> closeListeners =
      new ArrayList<>();

     /**
      * Adds a CloseListener to the list
      *
      * @param cl    CloseListener to add
      */
     public void addCloseListener(CloseListener cl) {
         closeListeners.add(cl);
     }

     /**
      * Removes a CloseListener from the list
      *
      * @param cl    CloseListener to remove
      */
     public void removeCloseListener(CloseListener cl) {
         closeListeners.remove(cl);
     }

     /**
      * Sends a CloseEvent to all CloseListeners in the list
      */
     protected void fireCloseEvent() {
         CloseEvent ce = new CloseEvent(this);

         for (CloseListener listener : closeListeners)
             listener.close(ce);
     }
}

package com.knutejohnson.classes;

import java.awt.*;
import java.util.*;

/**
  * The {@code CloseEvent} class is an event type to deliver a close message
  *
  * @author  Knute Johnson
  *
  * @see     CloseListener
  */

public class CloseEvent extends EventObject {
     /**
      * Constructs a new {@code CloseEvent}
      *
      * @param source    The Object generating the event
      */
     public CloseEvent(Object source) {
         super(source);
     }
}

package com.knutejohnson.classes;

/**
  * The {@code CloseListener} interface is implemented by classes wishing to
  * listen for a {@code CloseEvent}
  *
  * @author  Knute Johnson
  */

public interface CloseListener {
     /**
      * Override this method to receive {@code CloseEvent}s
      *
      * @param ce    The CloseEvent
      */
     public void close(CloseEvent ce);
}


-- 

Knute Johnson

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#28808

On Thu, 19 Jun 2014 22:03:10 -0700, Knute Johnson
<eternal@knutejohnson.com> wrote, quoted or indirectly quoted someone
who said :

>
>I hate that, look for it for an hour, write something here and then come 
>across the answer 2 minutes later.

see http://mindprod.com/jgloss/regex.html

I has the basics on one page.
-- 
Roedy Green Canadian Mind Products http://mindprod.com
Why program by hand in 5 days what you can spend
2 to 5 years of your life automating.
~ Terence Parr 1964-08-17

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#29481

On Thu, 19 Jun 2014 21:39:36 -0700, Knute Johnson
<eternal@knutejohnson.com> wrote, quoted or indirectly quoted someone
who said :

>How do you search for a String that contains a character such as ( that 
>is special to a regex?

I solved unworking Regex after unworking Regex with RegexBuddy that
lets you debug regexes in isolation and a bit at a time. Experimenting
is much faster than a compile test cycle, and you can see more what is
going on.  See http://mindprod.com/jgloss/regexbuddy.html
-- 
Roedy Green Canadian Mind Products http://mindprod.com
The art of strongly-typed language design is largely arranging 
that errors are automatically detected as soon as possible
in the compose, compile, run cycle.

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