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com.ibm.icu.util.StringTokenizer Maven / Gradle / Ivy
International Component for Unicode for Java (ICU4J) is a mature, widely used Java library
providing Unicode and Globalization support
/**
*******************************************************************************
* Copyright (C) 1996-2011, International Business Machines Corporation and *
* others. All Rights Reserved. *
*******************************************************************************
*/
package com.ibm.icu.util;
import java.util.Enumeration;
import java.util.NoSuchElementException;
import com.ibm.icu.text.UTF16;
import com.ibm.icu.text.UnicodeSet;
/**
* {@icuenhanced java.util.Calendar}.{@icu _usage_}
*
* The string tokenizer class allows an application to break a string
* into tokens by performing code point comparison.
* The StringTokenizer methods do not distinguish
* among identifiers, numbers, and quoted strings, nor do they recognize
* and skip comments.
*
* The set of delimiters (the codepoints that separate tokens) may be
* specified either at creation time or on a per-token basis.
*
*
* An instance of StringTokenizer behaves in one of three ways,
* depending on whether it was created with the returnDelims
* and coalesceDelims
* flags having the value true or false:
*
* If returnDelims is false, delimiter code points serve to
* separate tokens. A token is a maximal sequence of consecutive
* code points that are not delimiters.
* If returnDelims is true, delimiter code points are
* themselves considered to be tokens. In this case, if coalesceDelims is
* true, such tokens will be the maximal sequence of consecutive
* code points that are delimiters. If coalesceDelims is false,
* a token will be received for each delimiter code point.
*
* A token is thus either one
* delimiter code point, a maximal sequence of consecutive code points that
* are delimiters, or a maximal sequence of consecutive code
* points that are not delimiters.
*
*
* A StringTokenizer object internally maintains a current
* position within the string to be tokenized. Some operations advance this
* current position past the code point processed.
*
*
* A token is returned by taking a substring of the string that was used to
* create the StringTokenizer object.
*
*
* Example of the use of the default delimiter tokenizer.
*
* StringTokenizer st = new StringTokenizer("this is a test");
* while (st.hasMoreTokens()) {
* println(st.nextToken());
* }
*
* prints the following output:
*
* this
* is
* a
* test
*
* Example of the use of the tokenizer with user specified delimiter.
*
* StringTokenizer st = new StringTokenizer(
* "this is a test with supplementary characters \ud800\ud800\udc00\udc00",
* " \ud800\udc00");
* while (st.hasMoreTokens()) {
* println(st.nextToken());
* }
*
* prints the following output:
*
* this
* is
* a
* test
* with
* supplementary
* characters
* \ud800
* \udc00
*
{
// public constructors ---------------------------------------------
/**
* {@icu} Constructs a string tokenizer for the specified string. All
* characters in the delim argument are the delimiters for separating
* tokens.
* If the returnDelims flag is false, the delimiter characters are
* skipped and only serve as separators between tokens.
* If the returnDelims flag is true, then the delimiter characters
* are also returned as tokens, one per delimiter.
* @param str a string to be parsed.
* @param delim the delimiters.
* @param returndelims flag indicating whether to return the delimiters
* as tokens.
* @exception NullPointerException if str is null
* @stable ICU 2.4
*/
public StringTokenizer(String str, UnicodeSet delim, boolean returndelims)
{
this(str, delim, returndelims, false);
}
/**
* {@icu} Constructs a string tokenizer for the specified string. All
* characters in the delim argument are the delimiters for separating
* tokens.
*
If the returnDelims flag is false, the delimiter characters are
* skipped and only serve as separators between tokens.
* If the returnDelims flag is true, then the delimiter characters
* are also returned as tokens. If coalescedelims is true, one token
* is returned for each run of delimiter characters, otherwise one
* token is returned per delimiter. Since surrogate pairs can be
* delimiters, the returned token might be two chars in length.
* @param str a string to be parsed.
* @param delim the delimiters.
* @param returndelims flag indicating whether to return the delimiters
* as tokens.
* @param coalescedelims flag indicating whether to return a run of
* delimiters as a single token or as one token per delimiter.
* This only takes effect if returndelims is true.
* @exception NullPointerException if str is null
* @internal
* @deprecated This API is ICU internal only.
*/
public StringTokenizer(String str, UnicodeSet delim, boolean returndelims, boolean coalescedelims)
{
m_source_ = str;
m_length_ = str.length();
if (delim == null) {
m_delimiters_ = EMPTY_DELIMITER_;
}
else {
m_delimiters_ = delim;
}
m_returnDelimiters_ = returndelims;
m_coalesceDelimiters_ = coalescedelims;
m_tokenOffset_ = -1;
m_tokenSize_ = -1;
if (m_length_ == 0) {
// string length 0, no tokens
m_nextOffset_ = -1;
}
else {
m_nextOffset_ = 0;
if (!returndelims) {
m_nextOffset_ = getNextNonDelimiter(0);
}
}
}
/**
* {@icu} Constructs a string tokenizer for the specified string. The
* characters in the delim argument are the delimiters for separating
* tokens.
* Delimiter characters themselves will not be treated as tokens.
* @param str a string to be parsed.
* @param delim the delimiters.
* @exception NullPointerException if str is null
* @stable ICU 2.4
*/
public StringTokenizer(String str, UnicodeSet delim)
{
this(str, delim, false, false);
}
/**
* Constructs a string tokenizer for the specified string. All
* characters in the delim argument are the delimiters for separating
* tokens.
* If the returnDelims flag is false, the delimiter characters are
* skipped and only serve as separators between tokens.
* If the returnDelims flag is true, then the delimiter characters
* are also returned as tokens, one per delimiter.
* @param str a string to be parsed.
* @param delim the delimiters.
* @param returndelims flag indicating whether to return the delimiters
* as tokens.
* @exception NullPointerException if str is null
* @stable ICU 2.4
*/
public StringTokenizer(String str, String delim, boolean returndelims)
{
this(str, delim, returndelims, false); // java default behavior
}
/**
*
Constructs a string tokenizer for the specified string. All
* characters in the delim argument are the delimiters for separating
* tokens.
* If the returnDelims flag is false, the delimiter characters are
* skipped and only serve as separators between tokens.
* If the returnDelims flag is true, then the delimiter characters
* are also returned as tokens. If coalescedelims is true, one token
* is returned for each run of delimiter characters, otherwise one
* token is returned per delimiter. Since surrogate pairs can be
* delimiters, the returned token might be two chars in length.
* @param str a string to be parsed.
* @param delim the delimiters.
* @param returndelims flag indicating whether to return the delimiters
* as tokens.
* @param coalescedelims flag indicating whether to return a run of
* delimiters as a single token or as one token per delimiter.
* This only takes effect if returndelims is true.
* @exception NullPointerException if str is null
* @internal
* @deprecated This API is ICU internal only.
*/
public StringTokenizer(String str, String delim, boolean returndelims, boolean coalescedelims)
{
// don't ignore whitespace
m_delimiters_ = EMPTY_DELIMITER_;
if (delim != null && delim.length() > 0) {
m_delimiters_ = new UnicodeSet();
m_delimiters_.addAll(delim);
checkDelimiters();
}
m_coalesceDelimiters_ = coalescedelims;
m_source_ = str;
m_length_ = str.length();
m_returnDelimiters_ = returndelims;
m_tokenOffset_ = -1;
m_tokenSize_ = -1;
if (m_length_ == 0) {
// string length 0, no tokens
m_nextOffset_ = -1;
}
else {
m_nextOffset_ = 0;
if (!returndelims) {
m_nextOffset_ = getNextNonDelimiter(0);
}
}
}
/**
* Constructs a string tokenizer for the specified string. The
* characters in the delim argument are the delimiters for separating
* tokens.
* Delimiter characters themselves will not be treated as tokens.
* @param str a string to be parsed.
* @param delim the delimiters.
* @exception NullPointerException if str is null
* @stable ICU 2.4
*/
public StringTokenizer(String str, String delim)
{
// don't ignore whitespace
this(str, delim, false, false);
}
/**
* Constructs a string tokenizer for the specified string.
* The tokenizer uses the default delimiter set, which is
* " \t\n\r\f":
* the space character, the tab character, the newline character, the
* carriage-return character, and the form-feed character.
* Delimiter characters themselves will not be treated as tokens.
* @param str a string to be parsed
* @exception NullPointerException if str is null
* @stable ICU 2.4
*/
public StringTokenizer(String str)
{
this(str, DEFAULT_DELIMITERS_, false, false);
}
// public methods --------------------------------------------------
/**
* Tests if there are more tokens available from this tokenizer's
* string.
* If this method returns true , then a subsequent call to
* nextToken with no argument will successfully return a token.
* @return true if and only if there is at least one token
* in the string after the current position; false
* otherwise.
* @stable ICU 2.4
*/
public boolean hasMoreTokens()
{
return m_nextOffset_ >= 0;
}
/**
* Returns the next token from this string tokenizer.
* @return the next token from this string tokenizer.
* @exception NoSuchElementException if there are no more tokens in
* this tokenizer's string.
* @stable ICU 2.4
*/
public String nextToken()
{
if (m_tokenOffset_ < 0) {
if (m_nextOffset_ < 0) {
throw new NoSuchElementException("No more tokens in String");
}
// pre-calculations of tokens not done
if (m_returnDelimiters_) {
int tokenlimit = 0;
int c = UTF16.charAt(m_source_, m_nextOffset_);
boolean contains = delims == null
? m_delimiters_.contains(c)
: c < delims.length && delims[c];
if (contains) {
if (m_coalesceDelimiters_) {
tokenlimit = getNextNonDelimiter(m_nextOffset_);
} else {
tokenlimit = m_nextOffset_ + UTF16.getCharCount(c);
if (tokenlimit == m_length_) {
tokenlimit = -1;
}
}
}
else {
tokenlimit = getNextDelimiter(m_nextOffset_);
}
String result;
if (tokenlimit < 0) {
result = m_source_.substring(m_nextOffset_);
}
else {
result = m_source_.substring(m_nextOffset_, tokenlimit);
}
m_nextOffset_ = tokenlimit;
return result;
}
else {
int tokenlimit = getNextDelimiter(m_nextOffset_);
String result;
if (tokenlimit < 0) {
result = m_source_.substring(m_nextOffset_);
m_nextOffset_ = tokenlimit;
}
else {
result = m_source_.substring(m_nextOffset_, tokenlimit);
m_nextOffset_ = getNextNonDelimiter(tokenlimit);
}
return result;
}
}
// count was called before and we have all the tokens
if (m_tokenOffset_ >= m_tokenSize_) {
throw new NoSuchElementException("No more tokens in String");
}
String result;
if (m_tokenLimit_[m_tokenOffset_] >= 0) {
result = m_source_.substring(m_tokenStart_[m_tokenOffset_],
m_tokenLimit_[m_tokenOffset_]);
}
else {
result = m_source_.substring(m_tokenStart_[m_tokenOffset_]);
}
m_tokenOffset_ ++;
m_nextOffset_ = -1;
if (m_tokenOffset_ < m_tokenSize_) {
m_nextOffset_ = m_tokenStart_[m_tokenOffset_];
}
return result;
}
/**
* Returns the next token in this string tokenizer's string. First,
* the set of characters considered to be delimiters by this
* StringTokenizer object is changed to be the characters in
* the string delim . Then the next token in the string
* after the current position is returned. The current position is
* advanced beyond the recognized token. The new delimiter set
* remains the default after this call.
* @param delim the new delimiters.
* @return the next token, after switching to the new delimiter set.
* @exception NoSuchElementException if there are no more tokens in
* this tokenizer's string.
* @stable ICU 2.4
*/
public String nextToken(String delim)
{
m_delimiters_ = EMPTY_DELIMITER_;
if (delim != null && delim.length() > 0) {
m_delimiters_ = new UnicodeSet();
m_delimiters_.addAll(delim);
}
return nextToken(m_delimiters_);
}
/**
* {@icu} Returns the next token in this string tokenizer's string. First,
* the set of characters considered to be delimiters by this
* StringTokenizer object is changed to be the characters in
* the string delim . Then the next token in the string
* after the current position is returned. The current position is
* advanced beyond the recognized token. The new delimiter set
* remains the default after this call.
* @param delim the new delimiters.
* @return the next token, after switching to the new delimiter set.
* @exception NoSuchElementException if there are no more tokens in
* this tokenizer's string.
* @stable ICU 2.4
*/
public String nextToken(UnicodeSet delim)
{
m_delimiters_ = delim;
checkDelimiters();
m_tokenOffset_ = -1;
m_tokenSize_ = -1;
if (!m_returnDelimiters_) {
m_nextOffset_ = getNextNonDelimiter(m_nextOffset_);
}
return nextToken();
}
/**
* Returns the same value as the hasMoreTokens method.
* It exists so that this class can implement the
* Enumeration interface.
* @return true if there are more tokens;
* false otherwise.
* @see #hasMoreTokens()
* @stable ICU 2.4
*/
public boolean hasMoreElements()
{
return hasMoreTokens();
}
/**
* Returns the same value as the nextToken method, except
* that its declared return value is Object rather than
* String. It exists so that this class can implement the
* Enumeration interface.
* @return the next token in the string.
* @exception NoSuchElementException if there are no more tokens in
* this tokenizer's string.
* @see #nextToken()
* @stable ICU 2.4
*/
public Object nextElement()
{
return nextToken();
}
/**
* Calculates the number of times that this tokenizer's
* nextToken method can be called before it generates an
* exception. The current position is not advanced.
* @return the number of tokens remaining in the string using the
* current delimiter set.
* @see #nextToken()
* @stable ICU 2.4
*/
public int countTokens()
{
int result = 0;
if (hasMoreTokens()) {
if (m_tokenOffset_ >= 0) {
return m_tokenSize_ - m_tokenOffset_;
}
if (m_tokenStart_ == null) {
m_tokenStart_ = new int[TOKEN_SIZE_];
m_tokenLimit_ = new int[TOKEN_SIZE_];
}
do {
if (m_tokenStart_.length == result) {
int temptokenindex[] = m_tokenStart_;
int temptokensize[] = m_tokenLimit_;
int originalsize = temptokenindex.length;
int newsize = originalsize + TOKEN_SIZE_;
m_tokenStart_ = new int[newsize];
m_tokenLimit_ = new int[newsize];
System.arraycopy(temptokenindex, 0, m_tokenStart_, 0,
originalsize);
System.arraycopy(temptokensize, 0, m_tokenLimit_, 0,
originalsize);
}
m_tokenStart_[result] = m_nextOffset_;
if (m_returnDelimiters_) {
int c = UTF16.charAt(m_source_, m_nextOffset_);
boolean contains = delims == null
? m_delimiters_.contains(c)
: c < delims.length && delims[c];
if (contains) {
if (m_coalesceDelimiters_) {
m_tokenLimit_[result] = getNextNonDelimiter(
m_nextOffset_);
} else {
int p = m_nextOffset_ + 1;
if (p == m_length_) {
p = -1;
}
m_tokenLimit_[result] = p;
}
}
else {
m_tokenLimit_[result] = getNextDelimiter(m_nextOffset_);
}
m_nextOffset_ = m_tokenLimit_[result];
}
else {
m_tokenLimit_[result] = getNextDelimiter(m_nextOffset_);
m_nextOffset_ = getNextNonDelimiter(m_tokenLimit_[result]);
}
result ++;
} while (m_nextOffset_ >= 0);
m_tokenOffset_ = 0;
m_tokenSize_ = result;
m_nextOffset_ = m_tokenStart_[0];
}
return result;
}
// private data members -------------------------------------------------
/**
* Current offset to the token array. If the array token is not set up yet,
* this value is a -1
*/
private int m_tokenOffset_;
/**
* Size of the token array. If the array token is not set up yet,
* this value is a -1
*/
private int m_tokenSize_;
/**
* Array of pre-calculated tokens start indexes in source string terminated
* by -1.
* This is only set up during countTokens() and only stores the remaining
* tokens, not all tokens including parsed ones
*/
private int m_tokenStart_[];
/**
* Array of pre-calculated tokens limit indexes in source string.
* This is only set up during countTokens() and only stores the remaining
* tokens, not all tokens including parsed ones
*/
private int m_tokenLimit_[];
/**
* UnicodeSet containing delimiters
*/
private UnicodeSet m_delimiters_;
/**
* String to parse for tokens
*/
private String m_source_;
/**
* Length of m_source_
*/
private int m_length_;
/**
* Current position in string to parse for tokens
*/
private int m_nextOffset_;
/**
* Flag indicator if delimiters are to be treated as tokens too
*/
private boolean m_returnDelimiters_;
/**
* Flag indicating whether to coalesce runs of delimiters into single tokens
*/
private boolean m_coalesceDelimiters_;
/**
* Default set of delimiters \t\n\r\f
*/
private static final UnicodeSet DEFAULT_DELIMITERS_
= new UnicodeSet(0x09, 0x0a, 0x0c, 0x0d, 0x20, 0x20); // UnicodeSet("[ \t\n\r\f]", false)
/**
* Array size increments
*/
private static final int TOKEN_SIZE_ = 100;
/**
* A empty delimiter UnicodeSet, used when user specified null delimiters
*/
private static final UnicodeSet EMPTY_DELIMITER_ = UnicodeSet.EMPTY;
// private methods ------------------------------------------------------
/**
* Gets the index of the next delimiter after offset
* @param offset to the source string
* @return offset of the immediate next delimiter, otherwise
* (- source string length - 1) if there
* are no more delimiters after m_nextOffset
*/
private int getNextDelimiter(int offset)
{
if (offset >= 0) {
int result = offset;
int c = 0;
if (delims == null) {
do {
c = UTF16.charAt(m_source_, result);
if (m_delimiters_.contains(c)) {
break;
}
result ++;
} while (result < m_length_);
} else {
do {
c = UTF16.charAt(m_source_, result);
if (c < delims.length && delims[c]) {
break;
}
result ++;
} while (result < m_length_);
}
if (result < m_length_) {
return result;
}
}
return -1 - m_length_;
}
/**
* Gets the index of the next non-delimiter after m_nextOffset_
* @param offset to the source string
* @return offset of the immediate next non-delimiter, otherwise
* (- source string length - 1) if there
* are no more delimiters after m_nextOffset
*/
private int getNextNonDelimiter(int offset)
{
if (offset >= 0) {
int result = offset;
int c = 0;
if (delims == null) {
do {
c = UTF16.charAt(m_source_, result);
if (!m_delimiters_.contains(c)) {
break;
}
result ++;
} while (result < m_length_);
} else {
do {
c = UTF16.charAt(m_source_, result);
if (!(c < delims.length && delims[c])) {
break;
}
result ++;
} while (result < m_length_);
}
if (result < m_length_) {
return result;
}
}
return -1 - m_length_;
}
void checkDelimiters() {
if (m_delimiters_ == null || m_delimiters_.size() == 0) {
delims = new boolean[0];
} else {
int maxChar = m_delimiters_.getRangeEnd(m_delimiters_.getRangeCount()-1);
if (maxChar < 0x7f) {
delims = new boolean[maxChar+1];
for (int i = 0, ch; -1 != (ch = m_delimiters_.charAt(i)); ++i) {
delims[ch] = true;
}
} else {
delims = null;
}
}
}
private boolean[] delims;
}
