plugins/org.eclipse.viatra2.gtasm.patternmatcher.incremental.rete/src/org/eclipse/viatra2/gtasm/patternmatcher/incremental/rete/construction/psystem/ITypeInfoProviderConstraint.java

/*******************************************************************************
 * Copyright (c) 2004-2010 Gabor Bergmann and Daniel Varro
 * 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:
 *    Gabor Bergmann - initial API and implementation
 *******************************************************************************/

package org.eclipse.viatra2.gtasm.patternmatcher.incremental.rete.construction.psystem;

/**
 * @author Bergmann Gábor
 *
 */
public interface ITypeInfoProviderConstraint {
	
	/**
	 * Returns type information that is known about the variable if this constraint holds.
	 * Null if no such information is discernible.
	 * @param variable 
	 * @return the inferred type information, or TypeInfoSpecials.NO_TYPE_INFO_PROVIDED if no type information is inferrable. Never returns null.
	 */
	public Object getTypeInfo(PVariable variable);
	
	public static enum TypeInfoSpecials { 
		NO_TYPE_INFO_PROVIDED,
		ANY_UNARY,
		ANY_TERNARY;
		
		public static Object wrapUnary(Object typeKey) {
			return typeKey == null ? ITypeInfoProviderConstraint.TypeInfoSpecials.ANY_UNARY : typeKey;
		}
		public static Object unwrapUnary(Object typeKey) {
			return typeKey == ITypeInfoProviderConstraint.TypeInfoSpecials.ANY_UNARY ? null : typeKey;
		}
		public static Object wrapTernary(Object typeKey) {
			return typeKey == null ? ITypeInfoProviderConstraint.TypeInfoSpecials.ANY_TERNARY : typeKey;
		}
		public static Object unwrapTernary(Object typeKey) {
			return typeKey == ITypeInfoProviderConstraint.TypeInfoSpecials.ANY_TERNARY ? null : typeKey;
		}
		public static Object wrapAny(Object typeKey) {
			return typeKey == null ? ITypeInfoProviderConstraint.TypeInfoSpecials.NO_TYPE_INFO_PROVIDED : typeKey;
		}
	}

}