simpletokenmanager.java

SRI international 发布的OAA框架软件

package antlr_oaa;

/* ANTLR Translator Generator
 * Project led by Terence Parr at http://www.jGuru.com
 * Software rights: http://www.antlr.org/RIGHTS.html
 *
 * $Id: SimpleTokenManager.java,v 1.1 2002/11/08 17:37:41 agno Exp $
 */

import java.io.*;
import java.util.Hashtable;
import java.util.Enumeration;
import antlr_oaa.collections.impl.Vector;
class SimpleTokenManager implements TokenManager, Cloneable {
	protected int maxToken = Token.MIN_USER_TYPE;
	// Token vocabulary is Vector of String's
	protected Vector vocabulary;
	// Hash table is a mapping from Strings to TokenSymbol
	private Hashtable table;
	// the ANTLR tool
	protected Tool tool;
	// Name of the token manager
	protected String name;

	protected boolean readOnly = false;

	SimpleTokenManager(String name_, Tool tool_) {
		tool = tool_;
		name = name_;
		// Don't make a bigger vector than we need, because it will show up in output sets.
		vocabulary = new Vector(1);
		table = new Hashtable();

		// define EOF symbol
		TokenSymbol ts = new TokenSymbol("EOF");
		ts.setTokenType(Token.EOF_TYPE);
		define(ts);

		// define <null-tree-lookahead> but only in the vocabulary vector
		vocabulary.ensureCapacity(Token.NULL_TREE_LOOKAHEAD);
		vocabulary.setElementAt("NULL_TREE_LOOKAHEAD", Token.NULL_TREE_LOOKAHEAD);
	}
public Object clone() {
	SimpleTokenManager tm;
	try {
		tm = (SimpleTokenManager) super.clone();
		tm.vocabulary = (Vector) this.vocabulary.clone();
		tm.table = (Hashtable) this.table.clone();
		tm.maxToken = this.maxToken;
		tm.tool = this.tool;
		tm.name = this.name;
	} catch (CloneNotSupportedException e) {
		tool.panic("cannot clone token manager");
		return null;
	}
	return tm;
}
	/** define a token */
	public void define(TokenSymbol ts) {
		// Add the symbol to the vocabulary vector
		vocabulary.ensureCapacity(ts.getTokenType());
		vocabulary.setElementAt(ts.getId(), ts.getTokenType());
		// add the symbol to the hash table
		mapToTokenSymbol(ts.getId(), ts);
	}
	/** Simple token manager doesn't have a name -- must be set externally */
	public String getName() { return name; }
	/** Get a token symbol by index */
	public String getTokenStringAt(int idx) {
		return (String)vocabulary.elementAt(idx);
	}
	/** Get the TokenSymbol for a string */
	public TokenSymbol getTokenSymbol(String sym) {
		return (TokenSymbol)table.get(sym);
	}
	/** Get a token symbol by index */
	public TokenSymbol getTokenSymbolAt(int idx) {
		return getTokenSymbol(getTokenStringAt(idx));
	}
	/** Get an enumerator over the symbol table */
	public Enumeration getTokenSymbolElements() {
		return table.elements();
	}
public Enumeration getTokenSymbolKeys() {
	return table.keys();
}
	/** Get the token vocabulary (read-only).
	 * @return A Vector of TokenSymbol 
	 */
	public Vector getVocabulary() {
		return vocabulary;
	}
	/** Simple token manager is not read-only */
	public boolean isReadOnly() { return false; }
	/** Map a label or string to an existing token symbol */
	public void mapToTokenSymbol(String name, TokenSymbol sym) {
		table.put(name, sym);
	}
	/** Get the highest token type in use */
	public int maxTokenType() {
		return maxToken-1;
	}
	/** Get the next unused token type */
	public int nextTokenType() {
		return maxToken++;
	}
	/** Set the name of the token manager */
	public void setName(String name_) { name = name_; }
public void setReadOnly(boolean ro) {
	readOnly = ro;
}
	/** Is a token symbol defined? */
	public boolean tokenDefined(String symbol) {
		return table.containsKey(symbol);
	}
}