AOO410/main/xmerge/source/pexcel/java/org/openoffice/xmerge/converter/xml/sxc/pexcel/records/formula/SymbolLookup.java

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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
 * 
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package org.openoffice.xmerge.converter.xml.sxc.pexcel.records.formula;

import java.util.HashMap;

/**
 * This interface defines the attributes of a lookup table for this plugin.
 * Symbols will generally be either operators (_, -, *, etc) or funtion names.
 */
public abstract class SymbolLookup {

	protected HashMap stringToID = null;
	protected HashMap idToString = null;

	/**
	 * Perform lookup table specific initialization. This would typically entail loading values into
	 * the lookup table. It is best to optimize this process so that data is loaded statically and shared
	 * across all instances of the lookup table.
	 */
	abstract public void initialize();
	
	/**
	 * Associate a symbol with a  numeric value in the lookup table
	 * @param symbol	The symbol that will act as the key in the lookup table
	 * @param value		The value to be associated with a given symbol
	 */
	public void addEntry(String symbol, int id) {
    	Integer iObj = new Integer(id);
    	stringToID.put(symbol, iObj);
    	idToString.put(iObj, symbol);
	}
	
	/**
	 * Retrieve the symbol associated with a given identifier
	 * @param	id	The identfier for which we need to retieve the symbol string
	 * @return	The string associated with this identifier in the lookup table.
	 */
	public String getStringFromID(int id) {
		return (String)idToString.get(new Integer(id));
	}
	
	/**
	 * Retrieve the identifier associated with a given symbol
	 * @param	symbol	The symbol for which we need to retieve the identifier
	 * @throws UnsupportedFunctionException Thown when the symbol is not found in the lookup table
	 * @return	The identifier associated with this string in the lookup table.
	 */
	public int getIDFromString(String symbol) throws UnsupportedFunctionException {
		Integer i = (Integer)stringToID.get(symbol);
		if (i == null)
			throw new UnsupportedFunctionException("Token '" + symbol + "' not supported by Pocket Excel");
	
		return ((Integer)stringToID.get(symbol)).intValue();
	}
}