001: /*
002: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
003: *
004: * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
005: *
006: * The contents of this file are subject to the terms of either the GNU
007: * General Public License Version 2 only ("GPL") or the Common
008: * Development and Distribution License("CDDL") (collectively, the
009: * "License"). You may not use this file except in compliance with the
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011: * http://www.netbeans.org/cddl-gplv2.html
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014: * License. When distributing the software, include this License Header
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020: * License Header, with the fields enclosed by brackets [] replaced by
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022: * "Portions Copyrighted [year] [name of copyright owner]"
023: *
024: * Contributor(s):
025: *
026: * The Original Software is NetBeans. The Initial Developer of the Original
027: * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun
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040: */
041:
042: package org.netbeans.editor;
043:
044: /**
045: * Finders are used to find some information in document without
046: * creating copy of the data. They are used as arguments for
047: * <CODE>DocCache.find()</CODE>. During the find operation
048: * the <CODE>find()</CODE> method of the finder is called
049: * with some buffer of character data and some additional information.
050: * There are two possible search directions and therefore there
051: * are two finder types: Forward Finders (FwdFinder)
052: * and Backward Finders (BwdFinder)
053: *
054: * @author Miloslav Metelka
055: * @version 1.00
056: */
057:
058: public interface Finder {
059:
060: /** Reset method is used to initialize finder.
061: * It is called once at the begining of find. To be most effective
062: * <CODE>reset()</CODE> is called after both <CODE>setForward()</CODE>
063: * and <CODE>setLimitPos()</CODE> had been called.
064: */
065: public void reset();
066:
067: /** This is the most important function in finder. It can be called several
068: * times if the whole search area doesn't fit in the cache buffer.
069: * Usual forward search should look like this: <CODE>
070: * int offset = reqPos - bufferStartPos;
071: * while (offset < offset2) {
072: * if (buffer[offset]-meets-condition) {
073: * set-found-flag
074: * return offset + bufferStartPos;
075: * }
076: * offset++;
077: * }
078: * return offset + bufferStartPos;</CODE>
079: * Bakward search follows: <CODE>
080: * int offset = reqPos - bufferStartPos
081: * while (offset >= offset1) {
082: * if (buffer[offset]-meets-condition) {
083: * set-found-flag
084: * return offset + bufferStartPos;
085: * }
086: * offset--;
087: * }
088: * return offset + bufferStartPos;</CODE>
089: * Caution! Nothing can be written to the data comming in buffer to
090: * <CODE>find()</CODE> method because of performance reasons
091: * these are primary document data, not a copy.
092: * Buffer is always guaranteed to have at least one char - it is
093: * char standing at reqPos. However there can be calls to <CODE>find()</CODE>
094: * when there will be only that one character, so <CODE>find()</CODE> must
095: * must be prepared for this.
096: * Unlike calling <CODE>DocCache.find()</CODE> the offset1 < offset2 even
097: * for backward searches.
098: * @param bufferStartPos begining position of the buffer (not search area).
099: * @param buffer buffer with chars to be searched
100: * @param offset1 offset of begining of searchable area in buffer.
101: * No searching below this offset can be performed.
102: * @param offset2 offset of end of searchable area in buffer.
103: * No searching beyond this offset can be performed.
104: * @param reqPos required position. Initially it is the begining
105: * search position requested by caller. In subsequent calls
106: * it is the same value as returned from previous call
107: * to <CODE>find()</CODE> method.
108: * @param limitPos is filled with position beyond which search cannot go.
109: * (i.e. forward: pos < limitPos and backward: pos >= limitPos)
110: * Some finders i.e. finder that tries to find some word with
111: * whole-words-only flag turned on can benefit
112: * from this information. If the searched word is at the very end of
113: * the document the finder wouldn't normally find it as it would request
114: * the next buffer even when the whole word was matched because the finder
115: * needs to find white space to know the word ended there. However this
116: * would be beyond the search area so EOT exception would be raised.
117: * To correctly manage this situation finder must care for limitPos.
118: * When it sees the word and knows this is the last text in document
119: * it signals that it found the word.
120: * @return in case the string was found, <CODE>find()</CODE>
121: * method returns the position (not offset) where the string starts
122: * (and must also set some flag resulting to that <CODE>isFound()</CODE>
123: * method will return true).
124: * If the string was not yet found, the function should return
125: * position (not offset) where the next search should continue. If this
126: * position is greater or equal than limit position
127: * (lower than limit position for backward search),
128: * searching will stop resulting in -1 as returned position.
129: * The position returned will be passed as <CODE>reqPos</CODE> in next
130: * call to <CODE>find()</CODE> method.
131: */
132: public int find(int bufferStartPos, char buffer[], int offset1,
133: int offset2, int reqPos, int limitPos);
134:
135: /** Using this function caller determines if finder found
136: * desired string. The returned position of <CODE>find</CODE> method
137: * gives the position where the string occurs.
138: */
139: public boolean isFound();
140:
141: }
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