org.apache.hadoop.metrics.spi.CompositeContext.java Source code

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Here is the source code for org.apache.hadoop.metrics.spi.CompositeContext.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.metrics.spi;

import java.io.IOException;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.ArrayList;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.metrics.ContextFactory;
import org.apache.hadoop.metrics.MetricsContext;
import org.apache.hadoop.metrics.MetricsException;
import org.apache.hadoop.metrics.MetricsRecord;
import org.apache.hadoop.metrics.MetricsUtil;
import org.apache.hadoop.metrics.Updater;

/**
 * @deprecated in favor of <code>org.apache.hadoop.metrics2</code> usage.
 */
@Deprecated
@InterfaceAudience.Public
@InterfaceStability.Evolving
public class CompositeContext extends AbstractMetricsContext {

    private static final Log LOG = LogFactory.getLog(CompositeContext.class);
    private static final String ARITY_LABEL = "arity";
    private static final String SUB_FMT = "%s.sub%d";
    private final ArrayList<MetricsContext> subctxt = new ArrayList<MetricsContext>();

    @InterfaceAudience.Private
    public CompositeContext() {
    }

    @InterfaceAudience.Private
    public void init(String contextName, ContextFactory factory) {
        super.init(contextName, factory);
        int nKids;
        try {
            String sKids = getAttribute(ARITY_LABEL);
            nKids = Integer.valueOf(sKids);
        } catch (Exception e) {
            LOG.error("Unable to initialize composite metric " + contextName + ": could not init arity", e);
            return;
        }
        for (int i = 0; i < nKids; ++i) {
            MetricsContext ctxt = MetricsUtil.getContext(String.format(SUB_FMT, contextName, i), contextName);
            if (null != ctxt) {
                subctxt.add(ctxt);
            }
        }
    }

    @InterfaceAudience.Private
    @Override
    public MetricsRecord newRecord(String recordName) {
        return (MetricsRecord) Proxy.newProxyInstance(MetricsRecord.class.getClassLoader(),
                new Class[] { MetricsRecord.class }, new MetricsRecordDelegator(recordName, subctxt));
    }

    @InterfaceAudience.Private
    @Override
    protected void emitRecord(String contextName, String recordName, OutputRecord outRec) throws IOException {
        for (MetricsContext ctxt : subctxt) {
            try {
                ((AbstractMetricsContext) ctxt).emitRecord(contextName, recordName, outRec);
                if (contextName == null || recordName == null || outRec == null) {
                    throw new IOException(contextName + ":" + recordName + ":" + outRec);
                }
            } catch (IOException e) {
                LOG.warn("emitRecord failed: " + ctxt.getContextName(), e);
            }
        }
    }

    @InterfaceAudience.Private
    @Override
    protected void flush() throws IOException {
        for (MetricsContext ctxt : subctxt) {
            try {
                ((AbstractMetricsContext) ctxt).flush();
            } catch (IOException e) {
                LOG.warn("flush failed: " + ctxt.getContextName(), e);
            }
        }
    }

    @InterfaceAudience.Private
    @Override
    public void startMonitoring() throws IOException {
        for (MetricsContext ctxt : subctxt) {
            try {
                ctxt.startMonitoring();
            } catch (IOException e) {
                LOG.warn("startMonitoring failed: " + ctxt.getContextName(), e);
            }
        }
    }

    @InterfaceAudience.Private
    @Override
    public void stopMonitoring() {
        for (MetricsContext ctxt : subctxt) {
            ctxt.stopMonitoring();
        }
    }

    /**
     * Return true if all subcontexts are monitoring.
     */
    @InterfaceAudience.Private
    @Override
    public boolean isMonitoring() {
        boolean ret = true;
        for (MetricsContext ctxt : subctxt) {
            ret &= ctxt.isMonitoring();
        }
        return ret;
    }

    @InterfaceAudience.Private
    @Override
    public void close() {
        for (MetricsContext ctxt : subctxt) {
            ctxt.close();
        }
    }

    @InterfaceAudience.Private
    @Override
    public void registerUpdater(Updater updater) {
        for (MetricsContext ctxt : subctxt) {
            ctxt.registerUpdater(updater);
        }
    }

    @InterfaceAudience.Private
    @Override
    public void unregisterUpdater(Updater updater) {
        for (MetricsContext ctxt : subctxt) {
            ctxt.unregisterUpdater(updater);
        }
    }

    private static class MetricsRecordDelegator implements InvocationHandler {
        private static final Method m_getRecordName = initMethod();

        private static Method initMethod() {
            try {
                return MetricsRecord.class.getMethod("getRecordName", new Class[0]);
            } catch (Exception e) {
                throw new RuntimeException("Internal error", e);
            }
        }

        private final String recordName;
        private final ArrayList<MetricsRecord> subrecs;

        MetricsRecordDelegator(String recordName, ArrayList<MetricsContext> ctxts) {
            this.recordName = recordName;
            this.subrecs = new ArrayList<MetricsRecord>(ctxts.size());
            for (MetricsContext ctxt : ctxts) {
                subrecs.add(ctxt.createRecord(recordName));
            }
        }

        public Object invoke(Object p, Method m, Object[] args) throws Throwable {
            if (m_getRecordName.equals(m)) {
                return recordName;
            }
            assert Void.TYPE.equals(m.getReturnType());
            for (MetricsRecord rec : subrecs) {
                m.invoke(rec, args);
            }
            return null;
        }
    }

}