com.vaushell.superpipes.transforms.done.T_Done.java Source code

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Here is the source code for com.vaushell.superpipes.transforms.done.T_Done.java

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/*
 * Copyright (C) 2013 Fabien Vauchelles (fabien_AT_vauchelles_DOT_com).
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3, 29 June 2007, of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301  USA
 */

package com.vaushell.superpipes.transforms.done;

import com.vaushell.superpipes.dispatch.Message;
import com.vaushell.superpipes.transforms.A_Transform;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.Serializable;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import org.apache.commons.codec.digest.DigestUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Filter already known message by ID.
 *
 * @author Fabien Vauchelles (fabien_AT_vauchelles_DOT_com)
 */
public class T_Done extends A_Transform {
    // PUBLIC
    public T_Done() {
        super();

        this.ids = new HashSet<>();
        this.fields = new ArrayList<>();
    }

    @Override
    public void prepare() throws IOException {
        // Config
        path = getNode().getDispatcher().getDatas().resolve(Paths.get(getNode().getNodeID(), "done.dat"));

        Files.createDirectories(path.getParent());

        // Load previous ID
        if (Files.exists(path)) {
            try (final BufferedReader bfr = Files.newBufferedReader(path, Charset.forName("utf-8"))) {
                String line = bfr.readLine();
                while (line != null) {
                    final int ind = line.indexOf(' ');
                    if (ind < 0) {
                        ids.add(line);
                    } else {
                        ids.add(line.substring(0, ind));
                    }

                    line = bfr.readLine();
                }
            }
        }

        // Load fields list
        final String fieldsStr = getProperties().getConfigString("fields", null);
        if (fieldsStr != null) {
            for (final String field : fieldsStr.split(",")) {
                final String cleanField = field.trim();
                if (!cleanField.isEmpty()) {
                    fields.add(cleanField);
                }
            }
        }
    }

    @Override
    public Message transform(final Message message) throws Exception {
        if (LOGGER.isTraceEnabled()) {
            LOGGER.trace("[" + getNode().getNodeID() + "/" + getClass().getSimpleName() + "] transform message : "
                    + Message.formatSimple(message));
        }

        final String ID = buildID(message, fields);
        if (ids.contains(ID)) {
            return null;
        }

        // Save message ID. Won't be replay
        ids.add(ID);

        try (final BufferedWriter bfw = Files.newBufferedWriter(path, Charset.forName("utf-8"),
                StandardOpenOption.APPEND, StandardOpenOption.CREATE)) {
            bfw.write(ID);
            bfw.write(' ');
            bfw.write(Message.formatSimple(message));
            bfw.newLine();
        }

        return message;
    }

    @Override
    public void terminate() {
        // Nothing
    }

    // PRIVATE
    private static final Logger LOGGER = LoggerFactory.getLogger(T_Done.class);
    private final HashSet<String> ids;
    private Path path;
    private final List<String> fields;

    private String buildID(final Message message, final Collection<String> keys) {
        if (message.getPropertyCount() == 0) {
            return null;
        }

        final StringBuilder sb = new StringBuilder();

        for (final String key : keys) {
            final Serializable value = message.getProperty(key);
            if (value != null) {
                sb.append('$').append(key).append('#').append(value);
            }
        }

        if (sb.length() <= 0) {
            return buildID(message, message.getKeys());
        } else {
            return DigestUtils.md5Hex(sb.toString());
        }
    }
}