/*
 * 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;

import org.antlr.v4.runtime.misc.Interval;
import org.antlr.v4.runtime.misc.Pair;

import java.io.Serializable;

public class CommonToken implements WritableToken, Serializable {
	
An empty Pair which is used as the default value of source for tokens that do not have a source. /**
	 * An empty {@link Pair} which is used as the default value of
	 * {@link #source} for tokens that do not have a source.
	 */
	protected static final Pair<TokenSource, CharStream> EMPTY_SOURCE =
		new Pair<TokenSource, CharStream>(null, null);

	
This is the backing field for getType and setType. /**
	 * This is the backing field for {@link #getType} and {@link #setType}.
	 */
	protected int type;

	
This is the backing field for getLine and setLine. /**
	 * This is the backing field for {@link #getLine} and {@link #setLine}.
	 */
	protected int line;

	
This is the backing field for getCharPositionInLine and setCharPositionInLine. /**
	 * This is the backing field for {@link #getCharPositionInLine} and
	 * {@link #setCharPositionInLine}.
	 */
	protected int charPositionInLine = -1; // set to invalid position

	
This is the backing field for getChannel and setChannel. /**
	 * This is the backing field for {@link #getChannel} and
	 * {@link #setChannel}.
	 */
	protected int channel=DEFAULT_CHANNEL;

	
This is the backing field for getTokenSource and getInputStream. 
 These properties share a field to reduce the memory footprint of CommonToken. Tokens created by a CommonTokenFactory from the same source and input stream share a reference to the same Pair containing these values.
/**
	 * This is the backing field for {@link #getTokenSource} and
	 * {@link #getInputStream}.
	 *
	 * <p>
	 * These properties share a field to reduce the memory footprint of
	 * {@link CommonToken}. Tokens created by a {@link CommonTokenFactory} from
	 * the same source and input stream share a reference to the same
	 * {@link Pair} containing these values.</p>
	 */

	protected Pair<TokenSource, CharStream> source;

	
This is the backing field for getText when the token text is explicitly set in the constructor or via setText. 
See Also:
getText()/**
	 * This is the backing field for {@link #getText} when the token text is
	 * explicitly set in the constructor or via {@link #setText}.
	 *
	 * @see #getText()
	 */
	protected String text;

	
This is the backing field for getTokenIndex and setTokenIndex. /**
	 * This is the backing field for {@link #getTokenIndex} and
	 * {@link #setTokenIndex}.
	 */
	protected int index = -1;

	
This is the backing field for getStartIndex and setStartIndex. /**
	 * This is the backing field for {@link #getStartIndex} and
	 * {@link #setStartIndex}.
	 */
	protected int start;

	
This is the backing field for getStopIndex and setStopIndex. /**
	 * This is the backing field for {@link #getStopIndex} and
	 * {@link #setStopIndex}.
	 */
	protected int stop;

	
Constructs a new CommonToken with the specified token type. 
Params:
type – The token type./**
	 * Constructs a new {@link CommonToken} with the specified token type.
	 *
	 * @param type The token type.
	 */
	public CommonToken(int type) {
		this.type = type;
		this.source = EMPTY_SOURCE;
	}

	public CommonToken(Pair<TokenSource, CharStream> source, int type, int channel, int start, int stop) {
		this.source = source;
		this.type = type;
		this.channel = channel;
		this.start = start;
		this.stop = stop;
		if (source.a != null) {
			this.line = source.a.getLine();
			this.charPositionInLine = source.a.getCharPositionInLine();
		}
	}

	
Constructs a new CommonToken with the specified token type and text. 
Params:
type – The token type.
text – The text of the token./**
	 * Constructs a new {@link CommonToken} with the specified token type and
	 * text.
	 *
	 * @param type The token type.
	 * @param text The text of the token.
	 */
	public CommonToken(int type, String text) {
		this.type = type;
		this.channel = DEFAULT_CHANNEL;
		this.text = text;
		this.source = EMPTY_SOURCE;
	}

	
Constructs a new CommonToken as a copy of another Token. 
 If oldToken is also a CommonToken instance, the newly constructed token will share a reference to the text field and the Pair stored in source. Otherwise, text will be assigned the result of calling getText, and source will be constructed from the result of Token.getTokenSource and Token.getInputStream.
Params:
oldToken – The token to copy./**
	 * Constructs a new {@link CommonToken} as a copy of another {@link Token}.
	 *
	 * <p>
	 * If {@code oldToken} is also a {@link CommonToken} instance, the newly
	 * constructed token will share a reference to the {@link #text} field and
	 * the {@link Pair} stored in {@link #source}. Otherwise, {@link #text} will
	 * be assigned the result of calling {@link #getText}, and {@link #source}
	 * will be constructed from the result of {@link Token#getTokenSource} and
	 * {@link Token#getInputStream}.</p>
	 *
	 * @param oldToken The token to copy.
	 */
	public CommonToken(Token oldToken) {
		type = oldToken.getType();
		line = oldToken.getLine();
		index = oldToken.getTokenIndex();
		charPositionInLine = oldToken.getCharPositionInLine();
		channel = oldToken.getChannel();
		start = oldToken.getStartIndex();
		stop = oldToken.getStopIndex();

		if (oldToken instanceof CommonToken) {
			text = ((CommonToken)oldToken).text;
			source = ((CommonToken)oldToken).source;
		}
		else {
			text = oldToken.getText();
			source = new Pair<TokenSource, CharStream>(oldToken.getTokenSource(), oldToken.getInputStream());
		}
	}

	@Override
	public int getType() {
		return type;
	}

	@Override
	public void setLine(int line) {
		this.line = line;
	}

	@Override
	public String getText() {
		if ( text!=null ) {
			return text;
		}

		CharStream input = getInputStream();
		if ( input==null ) return null;
		int n = input.size();
		if ( start<n && stop<n) {
			return input.getText(Interval.of(start,stop));
		}
		else {
			return "<EOF>";
		}
	}

	
Explicitly set the text for this token. If {code text} is not null, then getText will return this value rather than extracting the text from the input. 
Params:
text – The explicit text of the token, or null if the text should be obtained from the input along with the start and stop indexes of the token./**
	 * Explicitly set the text for this token. If {code text} is not
	 * {@code null}, then {@link #getText} will return this value rather than
	 * extracting the text from the input.
	 *
	 * @param text The explicit text of the token, or {@code null} if the text
	 * should be obtained from the input along with the start and stop indexes
	 * of the token.
	 */
	@Override
	public void setText(String text) {
		this.text = text;
	}

	@Override
	public int getLine() {
		return line;
	}

	@Override
	public int getCharPositionInLine() {
		return charPositionInLine;
	}

	@Override
	public void setCharPositionInLine(int charPositionInLine) {
		this.charPositionInLine = charPositionInLine;
	}

	@Override
	public int getChannel() {
		return channel;
	}

	@Override
	public void setChannel(int channel) {
		this.channel = channel;
	}

	@Override
	public void setType(int type) {
		this.type = type;
	}

	@Override
	public int getStartIndex() {
		return start;
	}

	public void setStartIndex(int start) {
		this.start = start;
	}

	@Override
	public int getStopIndex() {
		return stop;
	}

	public void setStopIndex(int stop) {
		this.stop = stop;
	}

	@Override
	public int getTokenIndex() {
		return index;
	}

	@Override
	public void setTokenIndex(int index) {
		this.index = index;
	}

	@Override
	public TokenSource getTokenSource() {
		return source.a;
	}

	@Override
	public CharStream getInputStream() {
		return source.b;
	}

	@Override
	public String toString() {
		return toString(null);
	}

	public String toString(Recognizer r) {

		String channelStr = "";
		if ( channel>0 ) {
			channelStr=",channel="+channel;
		}
		String txt = getText();
		if ( txt!=null ) {
			txt = txt.replace("\n","\\n");
			txt = txt.replace("\r","\\r");
			txt = txt.replace("\t","\\t");
		}
		else {
			txt = "<no text>";
		}
		String typeString = String.valueOf(type);
		if ( r!=null ) {
			typeString = r.getVocabulary().getDisplayName(type);
		}
		return "[@"+getTokenIndex()+","+start+":"+stop+"='"+txt+"',<"+typeString+">"+channelStr+","+line+":"+getCharPositionInLine()+"]";
	}
}