com.sun.tools.xjc.reader.gbind.Choice Maven / Gradle / Ivy
/*
* Copyright (c) 1997, 2018 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;
/**
* {@link Expression} that represents the union of two expressions "A|B".
*
* @author Kohsuke Kawaguchi
*/
public final class Choice extends Expression {
/**
* "A" of "A|B".
*/
private final Expression lhs;
/**
* "B" of "A|B".
*/
private final Expression rhs;
/**
* Compute this value eagerly for better performance
*/
private final boolean isNullable;
public Choice(Expression lhs, Expression rhs) {
this.lhs = lhs;
this.rhs = rhs;
this.isNullable = lhs.isNullable() || rhs.isNullable();
}
boolean isNullable() {
return isNullable;
}
ElementSet lastSet() {
return ElementSets.union(lhs.lastSet(),rhs.lastSet());
}
void buildDAG(ElementSet incoming) {
lhs.buildDAG(incoming);
rhs.buildDAG(incoming);
}
public String toString() {
return '('+lhs.toString()+'|'+rhs.toString()+')';
}
}