org.springframework.data.hadoop.fs.FileSystemFactoryBean.java Source code

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Here is the source code for org.springframework.data.hadoop.fs.FileSystemFactoryBean.java

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/*
 * Copyright 2011 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.fs;

import java.net.URI;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.util.StringUtils;

/**
 * FactoryBean for creating Hadoop {@link FileSystem} instances. Useful for interacting with
 * HDFS from outside a Map Reduce job. If no parameter is given, a file system using the installed
 * Hadoop defaults will be created.
 * 
 * @author Costin Leau
 */
public class FileSystemFactoryBean implements InitializingBean, DisposableBean, FactoryBean<FileSystem> {

    private FileSystem fs;
    private Configuration configuration;
    private URI uri;
    private String user;
    private boolean closeAll = false;
    private boolean close = true;

    public void afterPropertiesSet() throws Exception {
        Configuration cfg = (configuration != null ? configuration : new Configuration(true));
        if (uri == null) {
            uri = FileSystem.getDefaultUri(cfg);
        }
        if (StringUtils.hasText(user)) {
            fs = FileSystem.get(uri, cfg, user);
        } else {
            fs = FileSystem.get(uri, cfg);
        }
    }

    public void destroy() throws Exception {
        if (fs != null && close) {
            fs.close();
        }
        fs = null;

        if (closeAll) {
            // TODO: potentially call close all just for the current user
            FileSystem.closeAll();
        }
    }

    public FileSystem getObject() throws Exception {
        return fs;
    }

    public Class<?> getObjectType() {
        return (fs != null ? fs.getClass() : FileSystem.class);
    }

    public boolean isSingleton() {
        return true;
    }

    /**
     * Sets the Hadoop configuration for this file system.
     * 
     * @param configuration The configuration to set.
     */
    public void setConfiguration(Configuration configuration) {
        this.configuration = configuration;
    }

    /**
     * Sets the URI (if available) for this file system.
     * 
     * @param uri The uri to set.
     */
    public void setUri(URI uri) {
        this.uri = uri;
    }

    /**
     * Sets the user impersonation (optional) for creating this file-system.
     * Should be used when running against a Hadoop Kerberos cluster. 
     * 
     * @param user user/group information
     */
    public void setUser(String user) {
        this.user = user;
    }

    /**
     * Indicates whether all the Hadoop file systems should be closed once this factory is destroyed.
     * False by default - should be turned on as a safety measure when the app controls the entire lifecycle of Hadoop inside
     * a JVM.
     *
     * @param closeAll the close all
     * @see FileSystem#closeAll()
     */
    public void setCloseAll(boolean closeAll) {
        this.closeAll = closeAll;
    }

    /**
     * Indicates whether the Hadoop file systems should be closed once this factory is destroyed.
     * True by default - should be turned off when running 'embedded' or if long running operations outlive the application context.
     *
     * @param close
     * @see FileSystem#close()
     */
    public void setClose(boolean close) {
        this.close = close;
    }
}