com.sun.tools.xjc.reader.gbind.ConnectedComponent Maven / Gradle / Ivy
/*
* Copyright (c) 1997, 2021 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0, which is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package com.sun.tools.xjc.reader.gbind;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
/**
* Represents one strongly-connected component
* of the {@link Element} graph.
*
* @author Kohsuke Kawaguchi
*/
public final class ConnectedComponent implements Iterable {
/**
* {@link Element}s that belong to this component.
*/
private final List elements = new ArrayList<>();
/*package*/ boolean isRequired;
/**
* Returns true iff this {@link ConnectedComponent}
* can match a substring whose length is greater than 1.
*
*
* That means this property will become a collection property.
*/
public final boolean isCollection() {
assert !elements.isEmpty();
// a strongly connected component by definition has a cycle,
// so if its size is bigger than 1 there must be a cycle.
if(elements.size()>1)
return true;
// if size is 1, it might be still forming a self-cycle
Element n = elements.get(0);
return n.hasSelfLoop();
}
/**
* Returns true iff this {@link ConnectedComponent}
* forms a cut set of a graph.
*
*
* That means any valid element sequence must have at least
* one value for this property.
*/
public final boolean isRequired() {
return isRequired;
}
/*package*/void add(Element e) {
assert !elements.contains(e);
elements.add(e);
}
@Override
public Iterator iterator() {
return elements.iterator();
}
/**
* Just produces debug representation
*/
@Override
public String toString() {
String s = elements.toString();
if(isRequired())
s += '!';
if(isCollection())
s += '*';
return s;
}
}