org.springframework.data.hadoop.store.strategy.naming.UuidFileNamingStrategy.java Source code

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Here is the source code for org.springframework.data.hadoop.store.strategy.naming.UuidFileNamingStrategy.java

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/*
 * Copyright 2014 the original author or authors.
 *
 * 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 org.springframework.data.hadoop.store.strategy.naming;

import java.util.UUID;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.fs.Path;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;

/**
 * A {@code FileNamingStrategy} which uses an uuid.
 *
 * @author Janne Valkealahti
 *
 */
public class UuidFileNamingStrategy extends AbstractFileNamingStrategy {

    private final static Log log = LogFactory.getLog(UuidFileNamingStrategy.class);

    private String uuid;

    private volatile String prefix = "-";

    /**
     * Instantiates a new uuid file naming strategy using
     * an {@link UUID}.
     */
    public UuidFileNamingStrategy() {
        this(UUID.randomUUID().toString());
    }

    /**
     * Instantiates a new uuid file naming strategy using
     * a given uuid string.
     *
     * @param uuid the uuid string
     */
    public UuidFileNamingStrategy(String uuid) {
        this.uuid = uuid;
    }

    /**
     * Instantiates a new uuid file naming strategy using
     * a given uuid string.
     *
     * @param uuid the uuid string
     * @param enabled the enabled
     */
    public UuidFileNamingStrategy(String uuid, boolean enabled) {
        this.uuid = uuid;
        setEnabled(enabled);
    }

    @Override
    public Path resolve(Path path) {
        if (isEnabled()) {
            if (path != null) {
                return new Path(path.getParent(), path.getName() + prefix + uuid);
            } else {
                return new Path(prefix + uuid);
            }
        } else {
            return path;
        }
    }

    @Override
    public Path init(Path path) {
        path = super.init(path);
        log.debug("Init using path=[" + path + "]");
        if (path != null && isEnabled()) {
            String oldName = path.getName();
            String newName = StringUtils.replace(oldName, prefix + uuid, "");
            if (!StringUtils.hasText(newName)) {
                path = null;
                log.debug("Removed last handled name part, returning null");
            } else if (!ObjectUtils.nullSafeEquals(oldName, newName)) {
                path = new Path(path.getParent(), newName);
                log.debug("Removed handled prefix, path is now " + newName);
            }
        }
        return path;
    }

    @Override
    public void next() {
    }

    @Override
    public UuidFileNamingStrategy createInstance() {
        UuidFileNamingStrategy instance = new UuidFileNamingStrategy(uuid, isEnabled());
        instance.setOrder(getOrder());
        instance.setEnabled(isEnabled());
        instance.setPrefix(prefix);
        return instance;
    }

    public void setUuid(String uuid) {
        this.uuid = uuid;
    }

    public String getUuid() {
        return uuid;
    }

    /**
     * Sets the prefix preceding uuid part.
     *
     * @param prefix the new prefix
     */
    public void setPrefix(String prefix) {
        Assert.notNull(prefix, "Prefix cannot be null");
        this.prefix = prefix;
    }

}