LinkedListToken.java

/*
 * LinkedListToken.java
 * 
 * Copyright (c) 2006 David Holroyd
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package uk.co.badgersinfoil.metaas.impl.antlr;

import org.antlr.runtime.ClassicToken;

public class LinkedListToken extends ClassicToken {
	private LinkedListToken prev = null;
	private LinkedListToken next = null;

	public LinkedListToken(int type, String text) {
		super(type, text);
	}

	public LinkedListToken getNext() {
		return next;
	}

	public void setNext(LinkedListToken next) {
		if (this == next) {
			throw new IllegalArgumentException("Token stream loop detected ("+toString()+")");
		}
		this.next = next;
		if (next != null) {
			next.prev = this;
		}
	}

	public LinkedListToken getPrev() {
		return prev;
	}

	public void setPrev(LinkedListToken prev) {
		if (this == prev) {
			throw new IllegalArgumentException("Token stream loop detected");
		}
		this.prev = prev;
		if (prev != null) {
			prev.next = this;
		}
	}

	public void afterInsert(LinkedListToken insert) {
		if (insert.getPrev() != null) {
			throw new IllegalArgumentException("afterInsert("+insert+") : prev was not null");
		}
		if (insert.getNext() != null) {
			throw new IllegalArgumentException("afterInsert("+insert+") : next was not null");
		}
		insert.next = next;
		insert.prev = this;
		if (next != null) {
			next.prev = insert;
		}
		next = insert;
	}

	public void beforeInsert(LinkedListToken insert) {
		if (insert.getPrev() != null) {
			throw new IllegalArgumentException("beforeInsert("+insert+") : prev was not null");
		}
		if (insert.getNext() != null) {
			throw new IllegalArgumentException("beforeInsert("+insert+") : next was not null");
		}
		insert.prev = prev;
		insert.next = this;
		if (prev != null) {
			prev.next = insert;
		}
		prev = insert;
	}

	public void delete() {
		if (prev != null) {
			prev.next = next;
		}
		if (next != null) {
			next.prev = prev;
		}
		next = prev = null;
	}
}