org.apache.nutch.indexer.NutchDocument.java Source code

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Here is the source code for org.apache.nutch.indexer.NutchDocument.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 org.apache.nutch.indexer;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.VersionMismatchException;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableUtils;
import org.apache.nutch.metadata.Metadata;

/** A {@link NutchDocument} is the unit of indexing. */
public class NutchDocument implements Writable, Iterable<Entry<String, List<String>>> {

    public static final byte VERSION = 1;

    private Map<String, List<String>> fields;

    private Metadata documentMeta;

    private float score;

    public NutchDocument() {
        fields = new HashMap<String, List<String>>();
        documentMeta = new Metadata();
        score = 0.0f;
    }

    public void add(String name, String value) {
        List<String> fieldValues = fields.get(name);
        if (fieldValues == null) {
            fieldValues = new ArrayList<String>();
        }
        fieldValues.add(value);
        fields.put(name, fieldValues);
    }

    private void addFieldUnprotected(String name, String value) {
        fields.get(name).add(value);
    }

    public String getFieldValue(String name) {
        List<String> fieldValues = fields.get(name);
        if (fieldValues == null) {
            return null;
        }
        if (fieldValues.size() == 0) {
            return null;
        }
        return fieldValues.get(0);
    }

    public List<String> getFieldValues(String name) {
        return fields.get(name);
    }

    public List<String> removeField(String name) {
        return fields.remove(name);
    }

    public Collection<String> getFieldNames() {
        return fields.keySet();
    }

    /** Iterate over all fields. */
    public Iterator<Entry<String, List<String>>> iterator() {
        return fields.entrySet().iterator();
    }

    public float getScore() {
        return score;
    }

    public void setScore(float score) {
        this.score = score;
    }

    public Metadata getDocumentMeta() {
        return documentMeta;
    }

    public void readFields(DataInput in) throws IOException {
        byte version = in.readByte();
        if (version != VERSION) {
            throw new VersionMismatchException(VERSION, version);
        }
        int size = WritableUtils.readVInt(in);
        for (int i = 0; i < size; i++) {
            String name = Text.readString(in);
            int numValues = WritableUtils.readVInt(in);
            fields.put(name, new ArrayList<String>());
            for (int j = 0; j < numValues; j++) {
                String value = Text.readString(in);
                addFieldUnprotected(name, value);
            }
        }
        score = in.readFloat();
        documentMeta.readFields(in);
    }

    public void write(DataOutput out) throws IOException {
        out.writeByte(VERSION);
        WritableUtils.writeVInt(out, fields.size());
        for (Map.Entry<String, List<String>> entry : fields.entrySet()) {
            Text.writeString(out, entry.getKey());
            List<String> values = entry.getValue();
            WritableUtils.writeVInt(out, values.size());
            for (String value : values) {
                Text.writeString(out, value);
            }
        }
        out.writeFloat(score);
        documentMeta.write(out);
    }

    /**
     * A utility-like method which can easily be used to write any
     * {@link org.apache.nutch.indexer.NutchDocument} object to string for simple
     * debugging.
     */
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("doc {\n");
        for (Entry<String, List<String>> entry : fields.entrySet()) {
            sb.append("\t");
            sb.append(entry.getKey());
            sb.append(":\t");
            sb.append(entry.getValue());
            sb.append("\n");
        }
        sb.append("}\n");
        return sb.toString();
    }
}