KeywordTable (Oracle Fusion Middleware Java API Reference for Oracle Extension SDK Reference)

It is used for mapping keyword keys ("public") to token constants (TK_PUBLIC).
No synchronization is provided as the hash table is not modified once it has been populated.
Table sizes are power of two as mod (%) operations are very expensive.

See Also:: Lexer

Constructor Summary
`KeywordTable(int numKeywords)` Constructs a new empty `KeywordTable` for the given size (number of keywords.)

Method Summary
`void`	`addKeyword(java.lang.String keyword, int token)` Adds the given keywords/token pair to the keyword table.
`static int`	`computeHash(char[] keyword)` Utility routine to calculate the hash value of a string used for this keyword table.
`static int`	`computeInsensitiveHash(char[] keyword)` Utility routine to calculate the (case insensitive) hash value of a string used for this keyword table.
`static int`	`computeInsensitivePartialHash(char nextChar, int lastHash)` Utility routine to calculate the (case insensitive) hash value of a keyword character by character (from left to right).
`static int`	`computePartialHash(char nextChar, int lastHash)` Utility routine to calculate the hash value of a keyword character by character (from left to right).
`int`	`lookupKeyword(ReadTextBuffer buffer, int startOffset, int endOffset, int precomputedHash)` Lookup the given keyword marked by the given start and end offset in the ReadTextBuffer, and return the matching token value, or Lexer.TK_NOT_FOUND if there is no such keyword in the table.
`void`	`setCaseSensitivity(boolean isCaseSensitive)` Sets the case sensitivity of the table as indiciated by client.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

KeywordTable

public KeywordTable(int numKeywords)

Constructs a new empty KeywordTable for the given size (number of keywords.)

Parameters:: numKeywords - number of expected keywords in table

Method Detail

setCaseSensitivity

public void setCaseSensitivity(boolean isCaseSensitive)

Sets the case sensitivity of the table as indiciated by client.

Parameters:: isCaseSensitive - true to perform case-sensitive lookups

addKeyword

public void addKeyword(java.lang.String keyword,
                       int token)

Adds the given keywords/token pair to the keyword table.

Parameters:: keyword - the keyword to use as a key to the hash table; token - the token value to use as the value

lookupKeyword

public int lookupKeyword(ReadTextBuffer buffer,
                         int startOffset,
                         int endOffset,
                         int precomputedHash)

Lookup the given keyword marked by the given start and end offset in the ReadTextBuffer, and return the matching token value, or Lexer.TK_NOT_FOUND if there is no such keyword in the table.

Parameters:: buffer - the TextBuffer of the keyword to look up; startOffset - the starting offset of the keyword in the buffer; endOffset - the ending offset of the keyword in the buffer
Returns:: the token value corresponding to the keyword or Lexer.TK_NOT_FOUND if the keyword is not found.

computeHash

public static int computeHash(char[] keyword)

Utility routine to calculate the hash value of a string used for this keyword table.

Parameters:: keyword - the keyword to hash
Returns:: the hash value

computeInsensitiveHash

public static int computeInsensitiveHash(char[] keyword)

Utility routine to calculate the (case insensitive) hash value of a string used for this keyword table.

Parameters:: keyword - the keyword to hash
Returns:: the hash value

computePartialHash

public static int computePartialHash(char nextChar,
                                     int lastHash)

Utility routine to calculate the hash value of a keyword character by character (from left to right). This is useful so that as we are looking for the end of the identifier in the Lexer, we can be calculating the hash value as we go.

Parameters:: nextChar - the next character in the sequence; lastHash - the last last value computed
Returns:: the new partial hash value

computeInsensitivePartialHash

public static int computeInsensitivePartialHash(char nextChar,
                                                int lastHash)

Utility routine to calculate the (case insensitive) hash value of a keyword character by character (from left to right). This is useful so that as we are looking for the end of the identifier in the Lexer, we can be calculating the hash value as we go.