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__Objective:__ to produce a searching text engine in the form of a JavaBean. Will be pluggable with multiple GUIs and TUIs.
This bean should contain the following features:
Inputs:
Return to ApplicationsGroup
package jos.utils.find;
/** FindTextBean
* This is the 'underlying architecture' or 'workhorse'.
* Please refer to JOS Collaborative Effort for more info.
*
* Author: Stefan Borg
* Started Date: 6 Nov 1997
* Edited Date: 11 Nov 1997
* Revise: 0.12
*/
import java.beans.Beans;
import java.io.*;
public class FindTextBean implements Serializable {
/** Instance variables.
*/
private boolean debug = false;
private Reader reader = null;
private char[] searchBuffer = null;
private long offset = 0;
private boolean ignoreCase = false;
private boolean wholeWords = false;
/** Internal variables.
*/
private char[] buffer = null;
private int searchLength = 0;
private int bufferOffset = 0;
/** Enables/disables system console messages for debuggin purposes.
*/
public void setDebug(boolean debug) { this.debug = debug; }
public boolean getDebug() { return debug; }
/** Set/gets source text for searching through.
*/
public void setReader(Reader reader) { this.reader = reader; }
public Reader getReader() { return reader; }
/** Set/gets search text for searching for.
*/
public void setSearchText(String searchText) {
searchBuffer = searchText.toCharArray();
searchLength = searchBuffer.length;
}
public String getSearchText() { return new String(searchBuffer); }
/** Set/gets option for ignoring case.
*/
public void setIgnoreCase(boolean ignoreCase) { this.ignoreCase = ignoreCase; }
public boolean getIgnoreCase() { return ignoreCase; }
/** Set/gets option for whole words only.
*/
public void setWholeWords(boolean wholeWords) { this.wholeWords = wholeWords; }
public boolean getWholeWords() { return wholeWords; }
/** Set/gets offset value to begin searching from. Later to become a protected method.
*/
public void setOffset(long offset) { this.offset = offset; }
public long getOffset() { return offset; }
/** Returns index value of found text. Maybe later to become a protected method.
* Queries:
* should reading depend on Reader.ready()??
*/
public long getIndex() throws InvalidSourceException {
// Checks all inputs are available
check();
long index = -1;
Reader tempReader = reader;
buffer = new char[searchLength];
long currentIndex = offset;
bufferOffset = 0;
out:
try {
// Skips offset value
tempReader.skip(currentIndex);
do {
// Reads stream into buffer
if (tempReader.read(buffer, bufferOffset,
(searchLength - bufferOffset)) == -1)
break out;
currentIndex += searchLength - bufferOffset;
// Until buffer matches search text
} while (!compareBuffer());
index = currentIndex - searchLength;
} catch (IOException io) {
io.getLocalizedMessage();
io.printStackTrace();
}
if (debug)
System.err.println("getIndex = " + index);
return index;
}
/** Returns true if arrays are equal.
*/
private boolean compareBuffer() {
boolean result = true;
try {
for (int i = 0; i < searchLength; i++)
result = compareCharacter(buffer[i], i);
} catch(NullPointerException npe) {
result = false;
}
// if unequal, check that start of search text is not in the buffer
if (!result) {
bufferOffset = checkBuffer();
}
return result;
}
/** Returns index of first character equal to first
* character of search text. Returns -1 if none found.
*/
private int checkBuffer() {
for (int i = 1; i < searchLength; i++) {
if (compareCharacter(buffer[i], 0)) {
if (debug)
System.err.println("found @:"+i);
return shiftBuffer(i);
}
}
return 0;
}
/** Shifts array into new position. Returns last index.
*/
private int shiftBuffer(int first) {
char[] tmpBuffer = buffer;
int i = 0;
for (; i < (searchLength - first); i++) {
buffer[i] = tmpBuffer[first + i];
}
if (debug)
System.err.println("shifted:"+buffer);
return i;
}
/** Returns true if comparison of characters at a position in the
* search text are equal.
*/
private boolean compareCharacter(char bufferChar, int pos) {
boolean result = true;
char searchChar = searchBuffer[pos];
if (ignoreCase) {
bufferChar = Character.toLowerCase(bufferChar);
searchChar = Character.toLowerCase(searchChar);
}
if (bufferChar != searchChar) {
result = false;
}
return result;
}
/** Returns true if Reader stream and search text are valid.
*/
private void check() throws InvalidSourceException {
if (reader == null) {
throw new InvalidSourceException();
}
}
/** InvalidSourceException class.
*/
class InvalidSourceException extends Exception {
InvalidSourceException() {
super("Reader source does not exist.");
}
};
/** For testing.
*/
public static void main(String args[]) {
try {
FindTextBean ftb = (FindTextBean)Beans.instantiate(null, "jos.utils.find.FindTextBean");
ftb.setDebug(true);
ftb.setReader(new FileReader("META-INF/MANIFEST.MF"));
ftb.setSearchText("bean");
ftb.setOffset(21);
ftb.setIgnoreCase(true);
System.out.println(ftb.getIndex());
} catch (Exception e) {
e.getLocalizedMessage();
e.printStackTrace();
}
}
}
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| Hosted by: |
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