SolrCopyConsumer.java

package org.icij.extract.solr;

import java.util.Map;
import java.util.HashMap;

import java.io.IOException;

import org.apache.solr.common.SolrDocument;
import org.apache.solr.common.SolrInputDocument;
import org.apache.solr.client.solrj.SolrClient;
import org.apache.solr.client.solrj.SolrServerException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A consumer that forces reindexing by copying a field onto itself
 * or onto another field.
 *
 * @author Matthew Caruana Galizia <mcaruana@icij.org>
 * @since 1.0.0-beta
 */
public class SolrCopyConsumer extends SolrMachineConsumer {

	private static final Logger logger = LoggerFactory.getLogger(SolrCopyConsumer.class);
	private static final String BAD_VALUE = "ERROR:SCHEMA-INDEX-MISMATCH,stringValue=";

	private final SolrClient client;
	private final Map<String, String> map;

	public SolrCopyConsumer(final SolrClient client, final Map<String, String> map) {
		super();
		this.client = client;
		this.map = map;
	}

	@Override
	protected void consume(final SolrDocument input) throws SolrServerException, IOException {
		final SolrInputDocument output = new SolrInputDocument();

		// Copy the source fields to the target fields.
		// Copy all the fields from the returned document. This ensures that wildcard matches work.
		for (String field : input.keySet()) {
			copyField(field, input, output);
		}

		logger.info(String.format("Adding document with ID \"%s\".", input.getFieldValue(idField)));
		client.add(output);
	}

	private void copyField(final String from, final SolrDocument input,
		final SolrInputDocument output) {
		final Map<String, Object> atomic = new HashMap<>();
		String to = map.get(from);

		// If there's no target field, copy the field onto itself.
		// This forces reindexing in Solr.
		if (null == to) {
			to = from;
		}

		// The ID field can't be set atomically.
		if (to.equals(idField)) {
			output.setField(to, input.getFieldValue(idField));
		} else {
			Object value = input.getFieldValue(from);

			// Fix bad values.
			if (value instanceof String && ((String) value).startsWith(BAD_VALUE)) {
				value = ((String) value).substring(BAD_VALUE.length());
			}

			atomic.put("set", value);
			output.setField(to, atomic);
		}
	}
}