InputFunction.java example

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/*
 * Copyright 2016 (C) Tom Parker <thpr@users.sourceforge.net>
 * 
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 * 
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package plugin.function;

import java.util.Arrays;

import pcgen.base.formula.base.DependencyManager;
import pcgen.base.formula.base.EvaluationManager;
import pcgen.base.formula.base.FormulaSemantics;
import pcgen.base.formula.base.Function;
import pcgen.base.formula.base.LegalScope;
import pcgen.base.formula.base.VariableLibrary;
import pcgen.base.formula.parse.ASTQuotString;
import pcgen.base.formula.parse.FormulaParserTreeConstants;
import pcgen.base.formula.parse.Node;
import pcgen.base.formula.parse.SimpleNode;
import pcgen.base.formula.visitor.DependencyVisitor;
import pcgen.base.formula.visitor.EvaluateVisitor;
import pcgen.base.formula.visitor.SemanticsVisitor;
import pcgen.base.formula.visitor.StaticVisitor;
import pcgen.base.util.FormatManager;
import pcgen.output.channel.ChannelUtilities;

/**
 * InputFunction is a function designed to allow pulling information from a channel (as
 * defined by the argument to the input function).
 */
public class InputFunction implements Function
{

	/**
	 * Returns the function name for this function. This is how it is called by
	 * a user in a formula.
	 */
	@Override
	public String getFunctionName()
	{
		return "INPUT";
	}

	@Override
	public final FormatManager<?> allowArgs(SemanticsVisitor visitor, Node[] args,
		FormulaSemantics semantics)
	{
		int argCount = args.length;
		if (argCount != 1)
		{
			semantics.setInvalid("Function " + getFunctionName()
				+ " received incorrect # of arguments, expected: 1 got "
				+ args.length + " " + Arrays.asList(args));
			return null;
		}
		//String node (name)
		Node inputNode = args[0];
		if (inputNode.getId() != FormulaParserTreeConstants.JJTQUOTSTRING)
		{
			semantics.setInvalid("Parse Error: Invalid Value: "
				+ ((SimpleNode) inputNode).getText() + " found in "
				+ inputNode.getClass().getName()
				+ " found in location requiring a literal"
				+ " String (cannot be evaluated)");
			return null;
		}
		String inputName = ((SimpleNode) inputNode).getText();
		String varName = ChannelUtilities.createVarName(inputName);
		VariableLibrary varLib =
				semantics.get(FormulaSemantics.FMANAGER).getFactory();
		LegalScope scope = semantics.get(FormulaSemantics.SCOPE);
		FormatManager<?> formatManager =
				varLib.getVariableFormat(scope, varName);
		if (formatManager == null)
		{
			semantics
				.setInvalid("Input Channel: " + varName + " was not found");
			return null;
		}
		return formatManager;
	}

	@Override
	public Object evaluate(EvaluateVisitor visitor, Node[] args,
		EvaluationManager manager)
	{
		String s = (String) args[0].jjtAccept(visitor, null);
		return visitor
			.visitVariable(ChannelUtilities.createVarName(s), manager);
	}

	@Override
	public Boolean isStatic(StaticVisitor visitor, Node[] args)
	{
		//Since we are dependent on user input, we can't be static
		return Boolean.FALSE;
	}

	@Override
	public void getDependencies(DependencyVisitor visitor,
		DependencyManager fdm, Node[] args)
	{
		ASTQuotString inputName = (ASTQuotString) args[0];
		String varName = inputName.getText();
		visitor.visitVariable(ChannelUtilities.createVarName(varName), fdm);
	}
}