com.linkedin.databus2.schemas.FileSystemVersionedSchemaSetProvider.java Source code

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Here is the source code for com.linkedin.databus2.schemas.FileSystemVersionedSchemaSetProvider.java

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package com.linkedin.databus2.schemas;
/*
 *
 * Copyright 2013 LinkedIn Corp. All rights reserved
 *
 * 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.
 *
*/

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.avro.Schema;
import org.apache.commons.io.IOUtils;
import org.apache.log4j.Logger;

/**
 * "Borrowed"  largely from com.linkedin.avro.FileSystemSchemaSetProvider
 */
public class FileSystemVersionedSchemaSetProvider implements VersionedSchemaSetProvider {
    public static final String MODULE = FileSystemVersionedSchemaSetProvider.class.getName();
    private static final Logger logger = Logger.getLogger(MODULE);
    static final String DEFAULT_SCHEMA_SUFFIX = ".avsc";
    static final Pattern FILE_NAME_PATTERN = Pattern.compile("(.*)\\.(\\d+).avsc");

    private final String schemaSuffix;
    private final File[] dirs;

    public FileSystemVersionedSchemaSetProvider(List<File> dirs) {
        this(dirs.toArray(new File[dirs.size()]));
    }

    public FileSystemVersionedSchemaSetProvider(File... dirs) {
        this(DEFAULT_SCHEMA_SUFFIX, dirs);
    }

    public FileSystemVersionedSchemaSetProvider(String schemaSuffix, File... dirs) {
        this.dirs = Arrays.copyOf(dirs, dirs.length);
        this.schemaSuffix = schemaSuffix;
    }

    @Override
    public VersionedSchemaSet loadSchemas() {
        try {
            VersionedSchemaSet schemas = new VersionedSchemaSet();
            for (File f : dirs)
                loadSchemas(f, schemas);
            return schemas;
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    private void loadSchemas(File f, VersionedSchemaSet schemas) throws IOException {
        if (!f.exists() || !f.canRead()) {
            throw new IllegalArgumentException("File does not exist or cannot be read: " + f.getAbsolutePath());
        }

        if (f.isDirectory()) {
            File[] files = f.listFiles();
            if (files != null) {
                for (File child : files)
                    loadSchemas(child, schemas);
            }
        } else if (f.getName().endsWith(schemaSuffix)) {
            VersionedSchemaId verSchemaId = parseSchemaVersion(f.getName());

            if (null != verSchemaId) {
                logger.info("Loading schema " + verSchemaId + " from file: " + f);
                InputStream input = new FileInputStream(f);
                try {
                    String schemaJson = IOUtils.toString(input);
                    schemas.add(new VersionedSchema(verSchemaId, Schema.parse(schemaJson), null));
                } finally {
                    IOUtils.closeQuietly(input);
                }
            }
        } else {
            logger.debug(
                    "Ignoring file " + f + " as it does not end with the required suffix '" + schemaSuffix + "'.");
        }
    }

    static VersionedSchemaId parseSchemaVersion(String fileName) throws IOException {
        Matcher matcher = FILE_NAME_PATTERN.matcher(fileName);
        if (matcher.matches()) {
            String baseName = matcher.group(1);
            short version = Short.parseShort(matcher.group(2));
            return new VersionedSchemaId(baseName, version);
        } else {
            logger.warn("Invalid file name: " + fileName);
            return null;
        }
    }

}