bundles/org.eclipse.uomo.ucum/src/main/java/org/eclipse/uomo/ucum/parsers/ExpressionComposer.java

/*******************************************************************************
 * Crown Copyright (c) 2006, 2008, Copyright (c) 2006, 2008 Kestral Computing P/L.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *    Kestral Computing P/L - initial implementation
 *******************************************************************************/

package org.eclipse.uomo.ucum.parsers;

import org.eclipse.uomo.ucum.expression.Component;
import org.eclipse.uomo.ucum.expression.Factor;
import org.eclipse.uomo.ucum.expression.Operator;
import org.eclipse.uomo.ucum.expression.Symbol;
import org.eclipse.uomo.ucum.expression.Term;

public class ExpressionComposer {


	public String compose(Term term) {
		if (term == null)
			return "1";
		StringBuilder bldr = new StringBuilder();
		composeTerm(bldr, term);
		return bldr.toString();
	}

	private void composeTerm(StringBuilder bldr, Term term) {
		if (term.getComp() != null)
			composeComp(bldr, term.getComp());
		if (term.getOp() != null)
			composeOp(bldr, term.getOp());
		if (term.getTerm() != null) { 
			composeTerm(bldr, term.getTerm());		
		}
	}

	private void composeComp(StringBuilder bldr, Component comp) {
		if (comp instanceof Factor)
			composeFactor(bldr, (Factor)comp);
		else if (comp instanceof Symbol)
			composeSymbol(bldr, (Symbol)comp);
		else if (comp instanceof Term) {
			bldr.append('(');
			composeTerm(bldr, (Term)comp);
			bldr.append(')');
		} else
			bldr.append('?');
	}

	private void composeSymbol(StringBuilder bldr, Symbol symbol) {
		if (symbol.getPrefix() != null) { 
			bldr.append(symbol.getPrefix().getCode());
		}
		bldr.append(symbol.getUnit().getCode());
		if (symbol.getExponent() != 1) { 
			bldr.append(symbol.getExponent());
		}
	}

	private void composeFactor(StringBuilder bldr, Factor comp) {
	   bldr.append(comp.getValue());		
	}

	private void composeOp(StringBuilder bldr, Operator op) {
		if (op == Operator.DIVISION)
			bldr.append("/");
		else
			bldr.append(".");
	}

}