/*
* ASTIterator.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;
import java.util.NoSuchElementException;
import uk.co.badgersinfoil.metaas.impl.antlr.LinkedListTree;
/**
* Iterates over the children of the given AST node.
*/
public class ASTIterator {
private LinkedListTree parent;
private int index = -1;
public ASTIterator(LinkedListTree parent) {
if (parent == null) {
throw new IllegalArgumentException("null not allowed");
}
this.parent = parent;
}
public boolean hasNext() {
return index < parent.getChildCount()-1;
}
public LinkedListTree next(int tokenType) {
if (!hasNext()) {
throw new IllegalStateException("expected " + ASTUtils.tokenName(tokenType) + " but reached last child");
}
if (parent.getChild(index+1).getType() != tokenType) {
throw new IllegalStateException("expected " + ASTUtils.tokenName(tokenType) + " but got " + parent.getChild(index+1));
}
return next();
}
public LinkedListTree next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
index++;
return (LinkedListTree)parent.getChild(index);
}
/**
* After a call to remove, another call to next() is required to access
* the element following the one just deleted.
*/
public void remove() {
parent.deleteChild(index);
index--;
}
public void replace(LinkedListTree replacement) {
parent.setChildWithTokens(index, replacement);
}
public LinkedListTree search(int tokenType) {
while (hasNext()) {
LinkedListTree ast = next();
if (ast.getType() == tokenType) {
return ast;
}
}
return null;
}
public LinkedListTree find(int tokenType) {
LinkedListTree result = search(tokenType);
if (result != null) {
return result;
}
throw new IllegalStateException("expected " + ASTUtils.tokenName(tokenType) + " but not found");
}
public void insertBeforeCurrent(LinkedListTree insert) {
parent.addChildWithTokens(index, insert);
}
public int getCurrentIndex() {
return index;
}
}