org.archive.io.CharSubSequence Maven / Gradle / Ivy
/*
* This file is part of the Heritrix web crawler (crawler.archive.org).
*
* Licensed to the Internet Archive (IA) by one or more individual
* contributors.
*
* The IA licenses this file to You 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 org.archive.io;
/**
* Provides a subsequence view onto a CharSequence.
*
* @author gojomo
* @version $Revision$, $Date$
*/
public class CharSubSequence implements CharSequence {
protected CharSequence inner;
protected int start;
protected int end;
public CharSubSequence(CharSequence inner, int start, int end) {
if (end < start) {
throw new IllegalArgumentException("Start " + start + " is > " +
" than end " + end);
}
if (end < 0 || start < 0) {
throw new IllegalArgumentException("Start " + start + " or end " +
end + " is < 0.");
}
if (inner == null) {
throw new NullPointerException("Passed charsequence is null.");
}
this.inner = inner;
this.start = start;
this.end = end;
}
/*
* (non-Javadoc)
* @see java.lang.CharSequence#length()
*/
public int length() {
return this.end - this.start;
}
/*
* (non-Javadoc)
* @see java.lang.CharSequence#charAt(int)
*/
public char charAt(int index) {
return this.inner.charAt(this.start + index);
}
/*
* (non-Javadoc)
* @see java.lang.CharSequence#subSequence(int, int)
*/
public CharSequence subSequence(int begin, int finish) {
return new CharSubSequence(this, begin, finish);
}
/*
* (non-Javadoc)
* @see java.lang.CharSequence#toString()
*/
public String toString() {
StringBuffer sb = new StringBuffer(length());
// could use StringBuffer.append(CharSequence) if willing to do 1.5 & up
for (int i = 0;i