org.apache.hadoop.hbase.coprocessor.BaseEnvironment.java Source code

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Here is the source code for org.apache.hadoop.hbase.coprocessor.BaseEnvironment.java

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/*
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.hadoop.hbase.coprocessor;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Coprocessor;
import org.apache.hadoop.hbase.CoprocessorEnvironment;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.HTableWrapper;
import org.apache.hadoop.hbase.client.Table;
import org.apache.hadoop.hbase.util.VersionInfo;
import org.apache.yetus.audience.InterfaceAudience;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.ExecutorService;

/**
 * Encapsulation of the environment of each coprocessor
 */
@InterfaceAudience.Private
public class BaseEnvironment<C extends Coprocessor> implements CoprocessorEnvironment<C> {
    private static final Log LOG = LogFactory.getLog(BaseEnvironment.class);

    /** The coprocessor */
    public C impl;
    /** Chaining priority */
    protected int priority = Coprocessor.PRIORITY_USER;
    /** Current coprocessor state */
    Coprocessor.State state = Coprocessor.State.UNINSTALLED;
    /** Accounting for tables opened by the coprocessor */
    protected List<Table> openTables = Collections.synchronizedList(new ArrayList<Table>());
    private int seq;
    private Configuration conf;
    private ClassLoader classLoader;

    /**
     * Constructor
     * @param impl the coprocessor instance
     * @param priority chaining priority
     */
    public BaseEnvironment(final C impl, final int priority, final int seq, final Configuration conf) {
        this.impl = impl;
        this.classLoader = impl.getClass().getClassLoader();
        this.priority = priority;
        this.state = Coprocessor.State.INSTALLED;
        this.seq = seq;
        this.conf = conf;
    }

    /** Initialize the environment */
    @Override
    public void startup() throws IOException {
        if (state == Coprocessor.State.INSTALLED || state == Coprocessor.State.STOPPED) {
            state = Coprocessor.State.STARTING;
            Thread currentThread = Thread.currentThread();
            ClassLoader hostClassLoader = currentThread.getContextClassLoader();
            try {
                currentThread.setContextClassLoader(this.getClassLoader());
                impl.start(this);
                state = Coprocessor.State.ACTIVE;
            } finally {
                currentThread.setContextClassLoader(hostClassLoader);
            }
        } else {
            LOG.warn("Not starting coprocessor " + impl.getClass().getName() + " because not inactive (state="
                    + state.toString() + ")");
        }
    }

    /** Clean up the environment */
    @Override
    public void shutdown() {
        if (state == Coprocessor.State.ACTIVE) {
            state = Coprocessor.State.STOPPING;
            Thread currentThread = Thread.currentThread();
            ClassLoader hostClassLoader = currentThread.getContextClassLoader();
            try {
                currentThread.setContextClassLoader(this.getClassLoader());
                impl.stop(this);
                state = Coprocessor.State.STOPPED;
            } catch (IOException ioe) {
                LOG.error("Error stopping coprocessor " + impl.getClass().getName(), ioe);
            } finally {
                currentThread.setContextClassLoader(hostClassLoader);
            }
        } else {
            LOG.warn("Not stopping coprocessor " + impl.getClass().getName() + " because not active (state="
                    + state.toString() + ")");
        }
        synchronized (openTables) {
            // clean up any table references
            for (Table table : openTables) {
                try {
                    ((HTableWrapper) table).internalClose();
                } catch (IOException e) {
                    // nothing can be done here
                    LOG.warn("Failed to close " + table.getName(), e);
                }
            }
        }
    }

    @Override
    public C getInstance() {
        return impl;
    }

    @Override
    public ClassLoader getClassLoader() {
        return classLoader;
    }

    @Override
    public int getPriority() {
        return priority;
    }

    @Override
    public int getLoadSequence() {
        return seq;
    }

    /** @return the coprocessor environment version */
    @Override
    public int getVersion() {
        return Coprocessor.VERSION;
    }

    /** @return the HBase release */
    @Override
    public String getHBaseVersion() {
        return VersionInfo.getVersion();
    }

    @Override
    public Configuration getConfiguration() {
        return conf;
    }

    /**
     * Open a table from within the Coprocessor environment
     * @param tableName the table name
     * @return an interface for manipulating the table
     * @exception IOException Exception
     */
    @Override
    public Table getTable(TableName tableName) throws IOException {
        return this.getTable(tableName, null);
    }

    /**
     * Open a table from within the Coprocessor environment
     * @param tableName the table name
     * @return an interface for manipulating the table
     * @exception IOException Exception
     */
    @Override
    public Table getTable(TableName tableName, ExecutorService pool) throws IOException {
        return HTableWrapper.createWrapper(openTables, tableName, this, pool);
    }
}