mailet/ai/src/main/java/org/apache/james/ai/classic/TokenCounter.java

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 * 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   *
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 * under the License.                                           *
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package org.apache.james.ai.classic;

import java.io.IOException;
import java.io.Reader;
import java.util.Map;

/**
 * Counts tokens occuring in stream.
 * Totals are added to map.
 */
public class TokenCounter extends Tokenizer {

    /** Counts for token indexed by token */
    private final Map<String, Integer> countsByToken;
    
    /**
     * Constructs a token counter to update values in given map.
     * @param countsByToken counts for token indexed by token, not null 
     */
    public TokenCounter(Map<String, Integer> countsByToken) {
        super();
        this.countsByToken = countsByToken;
    }

    /**
     * Tokenizes and adds token counts to map.
     * @param stream not null
     * @return this, not null
     * @throws IOException
     */
    public TokenCounter count(Reader stream) throws IOException {
        doTokenize(stream);
        return this;
    }
    
    /**
     * Updates count for token in map.
     */
    @Override
    protected void next(String token) {
        Integer value;

        if (countsByToken.containsKey(token)) {
            value = countsByToken.get(token) + 1;
        } else {
            value = 1;
        }

        countsByToken.put(token, value);        
    }

}