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/*
* 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.commons.lang.text;
import java.util.Arrays;
/**
* A matcher class that can be queried to determine if a character array
* portion matches.
*
* This class comes complete with various factory methods.
* If these do not suffice, you can subclass and implement your own matcher.
*
* @author Stephen Colebourne
* @since 2.2
* @version $Id: StrMatcher.java 437554 2006-08-28 06:21:41Z bayard $
*/
public abstract class StrMatcher {
/**
* Matches the comma character.
*/
private static final StrMatcher COMMA_MATCHER = new CharMatcher(',');
/**
* Matches the tab character.
*/
private static final StrMatcher TAB_MATCHER = new CharMatcher('\t');
/**
* Matches the space character.
*/
private static final StrMatcher SPACE_MATCHER = new CharMatcher(' ');
/**
* Matches the same characters as StringTokenizer,
* namely space, tab, newline, formfeed.
*/
private static final StrMatcher SPLIT_MATCHER = new CharSetMatcher(" \t\n\r\f".toCharArray());
/**
* Matches the String trim() whitespace characters.
*/
private static final StrMatcher TRIM_MATCHER = new TrimMatcher();
/**
* Matches the double quote character.
*/
private static final StrMatcher SINGLE_QUOTE_MATCHER = new CharMatcher('\'');
/**
* Matches the double quote character.
*/
private static final StrMatcher DOUBLE_QUOTE_MATCHER = new CharMatcher('"');
/**
* Matches the single or double quote character.
*/
private static final StrMatcher QUOTE_MATCHER = new CharSetMatcher("'\"".toCharArray());
/**
* Matches no characters.
*/
private static final StrMatcher NONE_MATCHER = new NoMatcher();
// -----------------------------------------------------------------------
/**
* Returns a matcher which matches the comma character.
*
* @return a matcher for a comma
*/
public static StrMatcher commaMatcher() {
return COMMA_MATCHER;
}
/**
* Returns a matcher which matches the tab character.
*
* @return a matcher for a tab
*/
public static StrMatcher tabMatcher() {
return TAB_MATCHER;
}
/**
* Returns a matcher which matches the space character.
*
* @return a matcher for a space
*/
public static StrMatcher spaceMatcher() {
return SPACE_MATCHER;
}
/**
* Matches the same characters as StringTokenizer,
* namely space, tab, newline and formfeed.
*
* @return the split matcher
*/
public static StrMatcher splitMatcher() {
return SPLIT_MATCHER;
}
/**
* Matches the String trim() whitespace characters.
*
* @return the trim matcher
*/
public static StrMatcher trimMatcher() {
return TRIM_MATCHER;
}
/**
* Returns a matcher which matches the single quote character.
*
* @return a matcher for a single quote
*/
public static StrMatcher singleQuoteMatcher() {
return SINGLE_QUOTE_MATCHER;
}
/**
* Returns a matcher which matches the double quote character.
*
* @return a matcher for a double quote
*/
public static StrMatcher doubleQuoteMatcher() {
return DOUBLE_QUOTE_MATCHER;
}
/**
* Returns a matcher which matches the single or double quote character.
*
* @return a matcher for a single or double quote
*/
public static StrMatcher quoteMatcher() {
return QUOTE_MATCHER;
}
/**
* Matches no characters.
*
* @return a matcher that matches nothing
*/
public static StrMatcher noneMatcher() {
return NONE_MATCHER;
}
/**
* Constructor that creates a matcher from a character.
*
* @param ch the character to match, must not be null
* @return a new Matcher for the given char
*/
public static StrMatcher charMatcher(char ch) {
return new CharMatcher(ch);
}
/**
* Constructor that creates a matcher from a set of characters.
*
* @param chars the characters to match, null or empty matches nothing
* @return a new matcher for the given char[]
*/
public static StrMatcher charSetMatcher(char[] chars) {
if (chars == null || chars.length == 0) {
return NONE_MATCHER;
}
if (chars.length == 1) {
return new CharMatcher(chars[0]);
}
return new CharSetMatcher(chars);
}
/**
* Constructor that creates a matcher from a string representing a set of characters.
*
* @param chars the characters to match, null or empty matches nothing
* @return a new Matcher for the given characters
*/
public static StrMatcher charSetMatcher(String chars) {
if (chars == null || chars.length() == 0) {
return NONE_MATCHER;
}
if (chars.length() == 1) {
return new CharMatcher(chars.charAt(0));
}
return new CharSetMatcher(chars.toCharArray());
}
/**
* Constructor that creates a matcher from a string.
*
* @param str the string to match, null or empty matches nothing
* @return a new Matcher for the given String
*/
public static StrMatcher stringMatcher(String str) {
if (str == null || str.length() == 0) {
return NONE_MATCHER;
}
return new StringMatcher(str);
}
//-----------------------------------------------------------------------
/**
* Constructor.
*/
protected StrMatcher() {
super();
}
/**
* Returns the number of matching characters, zero for no match.
*
* This method is called to check for a match.
* The parameter pos represents the current position to be
* checked in the string buffer (a character array which must
* not be changed).
* The API guarantees that pos is a valid index for buffer.
*
* The character array may be larger than the active area to be matched.
* Only values in the buffer between the specifed indices may be accessed.
*
* The matching code may check one character or many.
* It may check characters preceeding pos as well as those
* after, so long as no checks exceed the bounds specified.
*
* It must return zero for no match, or a positive number if a match was found.
* The number indicates the number of characters that matched.
*
* @param buffer the text content to match against, do not change
* @param pos the starting position for the match, valid for buffer
* @param bufferStart the first active index in the buffer, valid for buffer
* @param bufferEnd the end index (exclusive) of the active buffer, valid for buffer
* @return the number of matching characters, zero for no match
*/
public abstract int isMatch(char[] buffer, int pos, int bufferStart, int bufferEnd);
//-----------------------------------------------------------------------
/**
* Class used to define a set of characters for matching purposes.
*/
static final class CharSetMatcher extends StrMatcher {
/** The set of characters to match. */
private char[] chars;
/**
* Constructor that creates a matcher from a character array.
*
* @param chars the characters to match, must not be null
*/
CharSetMatcher(char chars[]) {
super();
this.chars = (char[]) chars.clone();
Arrays.sort(this.chars);
}
/**
* Returns whether or not the given charatcer matches.
*
* @param buffer the text content to match against, do not change
* @param pos the starting position for the match, valid for buffer
* @param bufferStart the first active index in the buffer, valid for buffer
* @param bufferEnd the end index of the active buffer, valid for buffer
* @return the number of matching characters, zero for no match
*/
public int isMatch(char[] buffer, int pos, int bufferStart, int bufferEnd) {
return Arrays.binarySearch(chars, buffer[pos]) >= 0 ? 1 : 0;
}
}
//-----------------------------------------------------------------------
/**
* Class used to define a character for matching purposes.
*/
static final class CharMatcher extends StrMatcher {
/** The character to match. */
private char ch;
/**
* Constructor that creates a matcher that matches a single character.
*
* @param ch the character to match
*/
CharMatcher(char ch) {
super();
this.ch = ch;
}
/**
* Returns whether or not the given character matches.
*
* @param buffer the text content to match against, do not change
* @param pos the starting position for the match, valid for buffer
* @param bufferStart the first active index in the buffer, valid for buffer
* @param bufferEnd the end index of the active buffer, valid for buffer
* @return the number of matching characters, zero for no match
*/
public int isMatch(char[] buffer, int pos, int bufferStart, int bufferEnd) {
return ch == buffer[pos] ? 1 : 0;
}
}
//-----------------------------------------------------------------------
/**
* Class used to define a set of characters for matching purposes.
*/
static final class StringMatcher extends StrMatcher {
/** The string to match, as a character array. */
private char[] chars;
/**
* Constructor that creates a matcher from a String.
*
* @param str the string to match, must not be null
*/
StringMatcher(String str) {
super();
chars = str.toCharArray();
}
/**
* Returns whether or not the given text matches the stored string.
*
* @param buffer the text content to match against, do not change
* @param pos the starting position for the match, valid for buffer
* @param bufferStart the first active index in the buffer, valid for buffer
* @param bufferEnd the end index of the active buffer, valid for buffer
* @return the number of matching characters, zero for no match
*/
public int isMatch(char[] buffer, int pos, int bufferStart, int bufferEnd) {
int len = chars.length;
if (pos + len > bufferEnd) {
return 0;
}
for (int i = 0; i < chars.length; i++, pos++) {
if (chars[i] != buffer[pos]) {
return 0;
}
}
return len;
}
}
//-----------------------------------------------------------------------
/**
* Class used to match no characters.
*/
static final class NoMatcher extends StrMatcher {
/**
* Constructs a new instance of NoMatcher.
*/
NoMatcher() {
super();
}
/**
* Always returns false.
*
* @param buffer the text content to match against, do not change
* @param pos the starting position for the match, valid for buffer
* @param bufferStart the first active index in the buffer, valid for buffer
* @param bufferEnd the end index of the active buffer, valid for buffer
* @return the number of matching characters, zero for no match
*/
public int isMatch(char[] buffer, int pos, int bufferStart, int bufferEnd) {
return 0;
}
}
//-----------------------------------------------------------------------
/**
* Class used to match whitespace as per trim().
*/
static final class TrimMatcher extends StrMatcher {
/**
* Constructs a new instance of TrimMatcher.
*/
TrimMatcher() {
super();
}
/**
* Returns whether or not the given charatcer matches.
*
* @param buffer the text content to match against, do not change
* @param pos the starting position for the match, valid for buffer
* @param bufferStart the first active index in the buffer, valid for buffer
* @param bufferEnd the end index of the active buffer, valid for buffer
* @return the number of matching characters, zero for no match
*/
public int isMatch(char[] buffer, int pos, int bufferStart, int bufferEnd) {
return buffer[pos] <= 32 ? 1 : 0;
}
}
}