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Statistical sampling library for use in virtdata libraries, based
on apache commons math 4
/*
* 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.
*/
package org.antlr.v4.runtime.tree.pattern;
/**
* Represents a placeholder tag in a tree pattern. A tag can have any of the
* following forms.
*
*
* - {@code expr}: An unlabeled placeholder for a parser rule {@code expr}.
* - {@code ID}: An unlabeled placeholder for a token of type {@code ID}.
* - {@code e:expr}: A labeled placeholder for a parser rule {@code expr}.
* - {@code id:ID}: A labeled placeholder for a token of type {@code ID}.
*
*
* This class does not perform any validation on the tag or label names aside
* from ensuring that the tag is a non-null, non-empty string.
*/
class TagChunk extends Chunk {
/**
* This is the backing field for {@link #getTag}.
*/
private final String tag;
/**
* This is the backing field for {@link #getLabel}.
*/
private final String label;
/**
* Construct a new instance of {@link TagChunk} using the specified tag and
* no label.
*
* @param tag The tag, which should be the name of a parser rule or token
* type.
*
* @exception IllegalArgumentException if {@code tag} is {@code null} or
* empty.
*/
public TagChunk(String tag) {
this(null, tag);
}
/**
* Construct a new instance of {@link TagChunk} using the specified label
* and tag.
*
* @param label The label for the tag. If this is {@code null}, the
* {@link TagChunk} represents an unlabeled tag.
* @param tag The tag, which should be the name of a parser rule or token
* type.
*
* @exception IllegalArgumentException if {@code tag} is {@code null} or
* empty.
*/
public TagChunk(String label, String tag) {
if (tag == null || tag.isEmpty()) {
throw new IllegalArgumentException("tag cannot be null or empty");
}
this.label = label;
this.tag = tag;
}
/**
* Get the tag for this chunk.
*
* @return The tag for the chunk.
*/
public final String getTag() {
return tag;
}
/**
* Get the label, if any, assigned to this chunk.
*
* @return The label assigned to this chunk, or {@code null} if no label is
* assigned to the chunk.
*/
public final String getLabel() {
return label;
}
/**
* This method returns a text representation of the tag chunk. Labeled tags
* are returned in the form {@code label:tag}, and unlabeled tags are
* returned as just the tag name.
*/
@Override
public String toString() {
if (label != null) {
return label + ":" + tag;
}
return tag;
}
}