no.trank.openpipe.solr.analysis.AnnotationTokenStream.java Source code

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Here is the source code for no.trank.openpipe.solr.analysis.AnnotationTokenStream.java

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/*
 * Copyright 2007  T-Rank AS
 * 
 * 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 no.trank.openpipe.solr.analysis;

import java.io.IOException;
import java.util.ListIterator;
import java.util.Set;

import org.apache.lucene.analysis.Token;
import org.apache.lucene.analysis.TokenStream;

import no.trank.openpipe.api.document.AnnotatedField;
import no.trank.openpipe.api.document.ResolvedAnnotation;

/**
 * @version $Revision$
 */
public class AnnotationTokenStream extends TokenStream {
    private ResolvedAnnotation[] anns;
    private ListIterator<ResolvedAnnotation>[] iterators;
    private String[] types;
    private int lastEnd = -1;

    public AnnotationTokenStream(AnnotatedField doc) {
        this(doc, doc.getAnnotationTypes());
    }

    @SuppressWarnings({ "unchecked" })
    public AnnotationTokenStream(AnnotatedField doc, Set<String> annotations) {
        types = annotations.toArray(new String[annotations.size()]);
        anns = new ResolvedAnnotation[annotations.size()];
        iterators = new ListIterator[annotations.size()];
        for (int i = 0; i < types.length; i++) {
            final ListIterator<ResolvedAnnotation> it = doc.iterator(types[i]);
            iterators[i] = it;
            anns[i] = nextOrNull(it);
        }
    }

    @Override
    public Token next() throws IOException {
        int idx = 0;
        ResolvedAnnotation ann = anns[idx];
        for (int i = 1; i < anns.length; i++) {
            final ResolvedAnnotation a2 = anns[i];
            if (a2 != null && (ann == null || a2.getStartPos() < ann.getStartPos()
                    || a2.getStartPos() == ann.getStartPos() && a2.getEndPos() < ann.getEndPos())) {
                ann = a2;
                idx = i;
            }
        }
        if (ann != null) {
            anns[idx] = nextOrNull(iterators[idx]);
            final boolean noIncr = lastEnd == ann.getEndPos();
            lastEnd = ann.getEndPos();
            if (ann instanceof Token) {
                return (Token) ann;
            }
            final Token token = new Token(ann.getValue(), ann.getStartPos(), lastEnd, types[idx]);
            if (noIncr) {
                token.setPositionIncrement(0);
            }
            return token;
        }
        return null;
    }

    private static ResolvedAnnotation nextOrNull(ListIterator<ResolvedAnnotation> it) {
        return it.hasNext() ? it.next() : null;
    }

}