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/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
* Use of this file is governed by the BSD 3-clause license that
* can be found in the LICENSE.txt file in the project root.
*/
using System;
using System.Collections.ObjectModel;
using Antlr4.Runtime.Misc;
using Antlr4.Runtime.Sharpen;
namespace Antlr4.Runtime.Atn
{
/// <summary>An ATN transition between any two ATN states.</summary>
/// <remarks>
/// An ATN transition between any two ATN states. Subclasses define
/// atom, set, epsilon, action, predicate, rule transitions.
/// <p>This is a one way link. It emanates from a state (usually via a list of
/// transitions) and has a target state.</p>
/// <p>Since we never have to change the ATN transitions once we construct it,
/// we can fix these transitions as specific classes. The DFA transitions
/// on the other hand need to update the labels as it adds transitions to
/// the states. We'll use the term Edge for the DFA to distinguish them from
/// ATN transitions.</p>
/// </remarks>
public abstract class Transition
{
public static readonly ReadOnlyCollection<string> serializationNames = new ReadOnlyCollection<string>(Arrays.AsList("INVALID", "EPSILON", "RANGE", "RULE", "PREDICATE", "ATOM", "ACTION", "SET", "NOT_SET", "WILDCARD", "PRECEDENCE"));
/// <summary>The target of this transition.</summary>
/// <remarks>The target of this transition.</remarks>
[NotNull]
public ATNState target;
protected internal Transition(ATNState target)
{
if (target == null)
{
throw new ArgumentNullException("target cannot be null.");
}
this.target = target;
}
public abstract TransitionType TransitionType
{
get;
}
/// <summary>Determines if the transition is an "epsilon" transition.</summary>
/// <remarks>
/// Determines if the transition is an "epsilon" transition.
/// <p>The default implementation returns
/// <see langword="false"/>
/// .</p>
/// </remarks>
/// <returns>
///
/// <see langword="true"/>
/// if traversing this transition in the ATN does not
/// consume an input symbol; otherwise,
/// <see langword="false"/>
/// if traversing this
/// transition consumes (matches) an input symbol.
/// </returns>
public virtual bool IsEpsilon
{
get
{
return false;
}
}
public virtual IntervalSet Label
{
get
{
return null;
}
}
public abstract bool Matches(int symbol, int minVocabSymbol, int maxVocabSymbol);
}
}