lucene.security.analysis.DocumentVisibilityTokenStream.java Source code

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Here is the source code for lucene.security.analysis.DocumentVisibilityTokenStream.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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 lucene.security.analysis;

import java.io.IOException;
import java.io.UnsupportedEncodingException;

import lucene.security.DocumentVisibility;

import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;

public class DocumentVisibilityTokenStream extends TokenStream {

    private static final String UTF_8 = "UTF-8";

    private final String _visiblity;
    private final CharTermAttribute _tokenAtt;
    private final int _length;

    private int _position;
    private boolean more = true;

    public DocumentVisibilityTokenStream(String visibility) {
        _tokenAtt = addAttribute(CharTermAttribute.class);
        _visiblity = visibility;
        _length = _visiblity.length();
    }

    public DocumentVisibilityTokenStream(DocumentVisibility visibility) {
        this(toString(visibility.flatten()));
    }

    @Override
    public final boolean incrementToken() throws IOException {
        if (more) {
            int next = findNextPipe(_position);
            if (next < 0) {
                more = false;
                next = _length;
            }
            _tokenAtt.setLength(0);
            if (hasSurroundingParens(next)) {
                _tokenAtt.append(_visiblity, _position + 1, next - 1);
            } else {
                _tokenAtt.append(_visiblity, _position, next);
            }
            _position = next + 1;
            return true;
        }
        return false;
    }

    private boolean hasSurroundingParens(int end) {
        if (_visiblity.charAt(_position) == '(') {
            if (_visiblity.charAt(end - 1) == ')') {
                return true;
            } else {
                throw new RuntimeException("This should never happen");
            }
        }
        return false;
    }

    private int findNextPipe(int position) {
        int p = 0;
        for (int i = position; i < _length; i++) {
            char c = _visiblity.charAt(i);
            switch (c) {
            case '(':
                p++;
                break;
            case ')':
                p--;
                break;
            case '|':
                if (p == 0) {
                    return i;
                }
            default:
                break;
            }
        }
        return -1;
    }

    public static String toString(byte[] bs) {
        try {
            return new String(bs, UTF_8);
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e);
        }
    }

}