org.eclipse.jdt.internal.compiler.lookup.ConstraintFormula Maven / Gradle / Ivy

/*******************************************************************************
 * Copyright (c) 2013, 2015 GK Software AG.
 * 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:
 *     Stephan Herrmann - initial API and implementation
 *     Lars Vogel  - Contributions for
 *     						Bug 473178
 *******************************************************************************/
package org.eclipse.jdt.internal.compiler.lookup;

import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

/**
 * Implementation of 18.1.2 in JLS8
 */
abstract class ConstraintFormula extends ReductionResult {

	static final List EMPTY_VARIABLE_LIST = Collections.emptyList();
	static final ConstraintFormula[] NO_CONSTRAINTS = new ConstraintTypeFormula[0];

	// constants for unicode debug output from ASCII source files:
	static final char LEFT_ANGLE_BRACKET = '\u27E8';
	static final char RIGHT_ANGLE_BRACKET = '\u27E9';

	public abstract Object reduce(InferenceContext18 inferenceContext) throws InferenceFailureException;

	Collection inputVariables(InferenceContext18 context) {
		return EMPTY_VARIABLE_LIST;
	}
	
	Collection outputVariables(InferenceContext18 context) {
		Set variables = new HashSet<>();
		this.right.collectInferenceVariables(variables);
		if (!variables.isEmpty())
			variables.removeAll(inputVariables(context));
		return variables;
	}

	public boolean applySubstitution(BoundSet solutionSet, InferenceVariable[] variables) {
		for (int i=0; i