Implements a StringTokenizer class for splitting a string into substrings using a set of delimiters.
#region Using Directives
using System;
using System.Collections.Generic;
#endregion
/*
* $author: QmQ
* $source: http://www.codeproject.com/useritems/SimpleStringTokenizer.asp
* $date: 10-June-2006
*/
namespace CBRSystem.Data
{
#region [Summary and remarks]
/// <summary>
/// Implements a StringTokenizer class for splitting a string
/// into substrings using a set of delimiters.
/// </summary>
/// <remarks>
/// C# version of the java.util.StringTokenizer class.
/// Basicly it's a wrapper class around the <c>String.Split</c> method.<pare/>
/// It implements all of it's Java equivalent methods apart from those only needed by the Enumeration interface.
/// All implemented Java-compilant methods have their C# equivalents in properties. They however differ in names
/// since Java uses the (Hungarian-like) notation <c>runMe()</c> while C# uses Camel-cased <c>RunMe()</c> and thus
/// Java's <c>nextToken()</c> method is just an alias of the <c>NextToken</c> property.
/// </remarks>
#endregion
public class StringTokenizer : IEnumerable<string>
{
/// <summary>
/// String conatining the default set of delimiters which are <c>" \t\n\r\f"</c>:
/// the space character, the tab character, the newline character, the carriage-return character, and the form-feed character.
/// </summary>
public const string DefaultDelimiters = " \t\n\r\f";
private readonly string delims = DefaultDelimiters;
private string[] tokens = null;
private int index = 0;
private string empty = String.Empty;
#region [Constructors]
/// <summary>
/// Constructs a string tokenizer for the specified string using the <see cref="F:DefaultDelimiters">default delimiters</see>.
/// </summary>
/// <param name="str">The string to be tokenized.</param>
/// <exception cref="System.NullReferenceException">Thrown when the passed string is <c>null</c></exception>
public StringTokenizer(string str)
{
Tokenize(str, false, false);
}
/// <summary>
/// Constructs a string tokenizer for the specified string using the given delimiters.
/// </summary>
/// <param name="str">The string to be tokenized.</param>
/// <param name="delims">The delimiters used to tokenize the string (each <see cref="!:char"/> will be used as a delimiter).</param>
/// <exception cref="System.NullReferenceException">Thrown when the passed string is <c>null</c></exception>
public StringTokenizer(string str, string delims)
{
if(delims!=null) this.delims = delims;
Tokenize(str, false, false);
}
/// <summary>
/// Constructs a string tokenizer for the specified string using the given delimiters.
/// </summary>
/// <param name="str">The string to be tokenized.</param>
/// <param name="delims">The delimiters used to tokenize the string.</param>
public StringTokenizer(string str, params char[] delims)
{
if (delims != null) this.delims = new string(delims);
Tokenize(str, false, false);
}
/// <summary>
/// Constructs a string tokenizer for the specified string using the given delimiters and optionally returning them as tokens.
/// </summary>
/// <param name="str">The string to be tokenized.</param>
/// <param name="delims">The delimiters used to tokenize the string (each <see cref="!:char"/> will be used as a delimiter).</param>
/// <param name="returnDelims">If set to <c>true</c> the encountered delimiters will also be returned as tokens.</param>
/// <exception cref="System.NullReferenceException">Thrown when the passed string is <c>null</c></exception>
public StringTokenizer(string str, string delims, bool returnDelims)
{
if (delims != null) this.delims = delims;
Tokenize(str, returnDelims, false);
}
/// <summary>
/// Constructs a string tokenizer for the specified string using the given delimiters,
/// optionally returning them as tokens. Also empty tokens may be returned using the <see cref="!:String.Empty"/> string.
/// </summary>
/// <param name="str">The string to be tokenized.</param>
/// <param name="delims">The delimiters used to tokenize the string (each <see cref="!:char"/> will be used as a delimiter).</param>
/// <param name="returnDelims">If set to <c>true</c> the encountered delimiters will also be returned as tokens.</param>
/// <param name="returnEmpty">If set to <c>true</c> empty tokens will also be returned.</param>
/// <exception cref="System.NullReferenceException">Thrown when the passed string is <c>null</c></exception>
public StringTokenizer(string str, string delims, bool returnDelims, bool returnEmpty)
{
if (delims != null) this.delims = delims;
Tokenize(str, returnDelims, returnEmpty);
}
/// <summary>
/// Constructs a string tokenizer for the specified string using the given delimiters,
/// optionally returning them as tokens. Also empty tokens may be returned using the <paramref name="empty"/> string.
/// </summary>
/// <param name="str">The string to be tokenized.</param>
/// <param name="delims">The delimiters used to tokenize the string (each <see cref="!:char"/> will be used as a delimiter).</param>
/// <param name="returnDelims">If set to <c>true</c> the encountered delimiters will also be returned as tokens.</param>
/// <param name="returnEmpty">If set to <c>true</c> empty tokens will also be returned.</param>
/// <param name="empty">The string to be returned as an empty token.</param>
/// <exception cref="System.NullReferenceException">Thrown when the passed string is <c>null</c></exception>
public StringTokenizer(string str, string delims, bool returnDelims, bool returnEmpty, string empty)
{
if (delims != null) this.delims = delims;
this.empty = empty;
Tokenize(str, returnDelims, returnEmpty);
}
#endregion
#region [The big tokenization method]
private void Tokenize(string str, bool returnDelims, bool returnEmpty)
{
if(returnDelims)
{
this.tokens = str.Split(this.delims.ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
List<string> tmp = new List<string>(tokens.Length << 1);
int delimIndex = str.IndexOfAny(this.delims.ToCharArray());
int tokensIndex = 0;
int prevDelimIdx = delimIndex-1;
if (delimIndex == 0)
do
{
tmp.Add(new string(str[delimIndex], 1));
prevDelimIdx = delimIndex++;
delimIndex = str.IndexOfAny(this.delims.ToCharArray(), delimIndex);
if (returnEmpty && delimIndex == prevDelimIdx + 1)
tmp.Add(this.empty);
} while (delimIndex == prevDelimIdx + 1);
while (delimIndex > -1)
{
tmp.Add(this.tokens[tokensIndex++]);
do
{
tmp.Add(new string(str[delimIndex], 1));
prevDelimIdx = delimIndex++;
delimIndex = str.IndexOfAny(this.delims.ToCharArray(), delimIndex);
if (returnEmpty && delimIndex == prevDelimIdx + 1)
tmp.Add(this.empty);
} while (delimIndex == prevDelimIdx + 1);
}
if (tokensIndex < tokens.Length)
tmp.Add(this.tokens[tokensIndex++]);
this.tokens = tmp.ToArray();
tmp = null;
}
else if (returnEmpty)
{
this.tokens = str.Split(this.delims.ToCharArray(), StringSplitOptions.None);
if (this.empty != String.Empty)
for(int i=0; i<this.tokens.Length; i++)
if (this.tokens[i] == String.Empty) this.tokens[i] = this.empty;
}
else
this.tokens = str.Split(this.delims.ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
}
#endregion
#region [Properties covering Java methods]
/// <summary>
/// Tests if there are more tokens available from this tokenizer's string.
/// If this method returns <c>true</c>, then a subsequent
/// use of the <see cref="P:NextToken"/> property will successfully return a token.
/// </summary>
/// <value>
/// <c>true</c> if more tokens are available; otherwise <c>false</c>.
/// </value>
public bool HasMoreTokens
{
get { return this.index < this.tokens.Length; }
}
/// <summary>
/// Gets the next token.
/// </summary>
/// <value>The next token.</value>
/// <exception cref="System.IndexOutOfRangeException">Thrown when trying to get a token which doesn't exist.
/// Usually caused by not checking if the <see cref="P:HasMoreTokens"/> property returns <c>true</c> before trying to get the next token.</exception>
public string NextToken
{
get { return this.tokens[index++]; }
}
/// <summary>
/// Counts the <see cref="!:remaining"/> tokens - the number of times the
/// <see cref="P:NextToken"/> property can be used before it throws an exception.
/// </summary>
/// <value>The number of remaining tokens.</value>
/// <seealso cref="P:Count"/>
public int CountTokens
{
get { return this.tokens.Length - this.index; }
}
#endregion
#region [New methods/properties]
/// <summary>
/// Gets the total number of tokens extracted.
/// </summary>
/// <remarks>
/// <see cref="!:Equivalent not available in Java!"/>
/// This property returns the total number of extracted tokens,
/// contrary to <see cref="P:CountTokens"/>.
/// </remarks>
/// <value>The number of tokens extracted.</value>
/// <seealso cref="P:StringTokenizer.CountTokens"/>
public int Count
{
get { return this.tokens.Length; }
}
/// <summary>
/// Gets the token with the specified index from the tokenizer without moving the current position index.
/// </summary>
/// <remarks><see cref="!:Equivalent not available in Java!"/></remarks>
/// <param name="index">The index of the token to get.</param>
/// <value>The token with the given index</value>
/// <exception cref="System.IndexOutOfRangeException">Thrown when trying to get a token which doesn't exist, that is when <see cref="!:index"/> is equal or greater then <see cref="!:Count"/> or <see cref="!:index"/> is negative.</exception>
public string this[int index]
{
get { return this.tokens[index]; }
}
/// <summary>
/// Resets the current position index so that the tokens can be extracted again.
/// </summary>
/// <remarks><see cref="!:Equivalent not available in Java!"/></remarks>
public void Reset()
{
this.index = 0;
}
/// <summary>
/// Gets the currently set string for empty tokens.
/// </summary>
/// <remarks>Default is <c>System.String.Empty</c></remarks>
/// <value>The empty token string.</value>
public string EmptyString
{
get { return this.empty; }
}
#endregion
#region [Java-compilant methods]
/*
/// <summary>
/// Tests if there are more tokens available from this tokenizer's string.
/// If this method returns <c>true</c>, then a subsequent call to <see cref="M:nextToken"/> will successfully return a token.
/// </summary>
/// <returns>
/// <c>true</c> if and only if there is at least one token in the string after the current position; otherwise <c>false</c>.
/// </returns>
/// <seealso cref="M:nextToken"/>
public bool hasMoreTokens()
{
return HasMoreTokens;
}
/// <summary>
/// Returns the next token from this string tokenizer.
/// </summary>
/// <returns>The next token from this string tokenizer.</returns>
public string nextToken()
{
return NextToken;
}
/// <summary>
/// Calculates the number of times that this tokenizer's <see cref="M:nextToken"/> method can be called before it generates an exception. The current position is not advanced.
/// </summary>
/// <returns>The number of tokens remaining in the string using the current delimiter set.</returns>
public int countTokens()
{
return CountTokens;
}
*/
#endregion
#region [IEnumerable implementation]
/// <summary>
/// Returns an enumerator that iterates through the collection.
/// </summary>
/// <returns>
/// A <see cref="T:System.Collections.Generic.IEnumerator"/> that can be used to iterate through the collection.
/// </returns>
public IEnumerator<string> GetEnumerator()
{
while (this.HasMoreTokens)
yield return this.NextToken;
}
System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
#endregion
}
}
Related examples in the same category
