co.cask.cdap.logging.serialize.LogSchema.java Source code

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Here is the source code for co.cask.cdap.logging.serialize.LogSchema.java

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/*
 * Copyright  2014 Cask Data, Inc.
 *
 * 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.
 */

package co.cask.cdap.logging.serialize;

import org.apache.avro.Schema;
import org.apache.hadoop.io.MD5Hash;

import java.io.IOException;
import java.net.URL;

/**
 * Handles generation of schema for logging.
 */
public final class LogSchema {
    private static final String SCHEMA_LOCATION = "/logging/schema/LoggingEvent.avsc";
    private static final URL SCHEMA_URL = LogSchema.class.getResource(SCHEMA_LOCATION);
    private final Schema schema;
    private final SchemaHash schemaHash;

    public LogSchema() throws IOException {
        this.schema = new Schema.Parser().parse(getClass().getResourceAsStream(SCHEMA_LOCATION));
        this.schemaHash = new SchemaHash(MD5Hash.digest(getClass().getResourceAsStream(SCHEMA_LOCATION)));
    }

    public Schema getAvroSchema() {
        return schema;
    }

    public SchemaHash getSchemaHash() {
        return schemaHash;
    }

    public static URL getSchemaURL() {
        return SCHEMA_URL;
    }

    /**
     * Used to generate hash for schema.
     */
    public static final class SchemaHash {
        private final MD5Hash md5Hash;

        public SchemaHash(MD5Hash md5Hash) {
            this.md5Hash = md5Hash;
        }

        @Override
        public boolean equals(Object o) {
            if (this == o) {
                return true;
            }
            if (o == null || getClass() != o.getClass()) {
                return false;
            }

            SchemaHash that = (SchemaHash) o;
            return !(md5Hash != null ? !md5Hash.equals(that.md5Hash) : that.md5Hash != null);
        }

        @Override
        public int hashCode() {
            return md5Hash != null ? md5Hash.hashCode() : 0;
        }

        @Override
        public String toString() {
            return md5Hash.toString();
        }
    }
}