juzu.impl.common.CharStream Maven / Gradle / Ivy
/*
* Copyright 2013 eXo Platform SAS
*
* 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 juzu.impl.common;
import java.util.NoSuchElementException;
/**
* Wraps a {@link CharSequence} to become a stream of chars.
*
* @author Julien Viet
*/
public class CharStream {
/** . */
private final CharSequence s;
/** . */
private int index;
/**
* Create a new stream of the provided sequence.
*
* @param s the sequence
* @throws NullPointerException if the sequence is null
*/
public CharStream(CharSequence s) throws NullPointerException {
if (s == null) {
throw new NullPointerException("No null sequence accepted");
}
//
this.s = s;
this.index = 0;
}
public int getIndex() {
return index;
}
public void reset() {
index = 0;
}
public boolean hasNext() {
return has(0);
}
public boolean hasNext(char c) {
return has(0, c);
}
public boolean has(int delta) {
return index + delta < s.length();
}
public boolean has(int delta, char c) {
int offset = index + delta;
return offset < s.length() && s.charAt(offset) == c;
}
public boolean next(char c) {
boolean a = index < s.length() && s.charAt(index) == c;
if (a) {
index++;
}
return a;
}
public Character peek() {
return peek(0);
}
public Character peek(int delta) {
int offset = index + delta;
if (offset < s.length()) {
return s.charAt(offset);
}
else {
return null;
}
}
public char next() throws NoSuchElementException {
if (hasNext()) {
return s.charAt(index++);
}
else {
throw new NoSuchElementException();
}
}
}