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      1 /*
      2  * Copyright (C) 2014 Google Inc.
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  * http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.google.caliper.runner;
     18 
     19 import static com.google.common.base.Preconditions.checkState;
     20 
     21 import com.google.caliper.runner.TrialOutputFactory.FileAndWriter;
     22 
     23 import java.io.Closeable;
     24 import java.io.File;
     25 import java.io.IOException;
     26 import java.io.PrintWriter;
     27 import java.util.UUID;
     28 
     29 import javax.annotation.concurrent.GuardedBy;
     30 import javax.inject.Inject;
     31 
     32 /**
     33  * A logger to write trial output to a file.
     34  */
     35 @TrialScoped final class TrialOutputLogger implements Closeable {
     36   @GuardedBy("this")
     37   private File file;
     38 
     39   @GuardedBy("this")
     40   private PrintWriter writer;
     41 
     42   private final int trialNumber;
     43   private final Experiment experiment;
     44   private final UUID trialId;
     45   private final TrialOutputFactory outputManager;
     46 
     47   @Inject TrialOutputLogger(TrialOutputFactory outputManager, @TrialNumber int trialNumber,
     48       @TrialId UUID trialId, Experiment experiment) {
     49     this.outputManager = outputManager;
     50     this.trialNumber = trialNumber;
     51     this.trialId = trialId;
     52     this.experiment = experiment;
     53   }
     54 
     55   /** Opens the trial output file. */
     56   synchronized void open() throws IOException {
     57     if (writer == null) {
     58       FileAndWriter fileAndWriter = outputManager.getTrialOutputFile(trialNumber);
     59       file = fileAndWriter.file;
     60       writer = fileAndWriter.writer;
     61     }
     62   }
     63 
     64   /**
     65    * Ensures that the writer has been opened. also creates a happens-before edge that ensures that
     66    * writer is visible (and non-null) after a non-exceptional return from this method.
     67    */
     68   private synchronized void checkOpened() {
     69     checkState(writer != null, "The logger is not open");
     70   }
     71 
     72   /** Prints header information to the file. */
     73   synchronized void printHeader() {
     74     checkOpened();
     75     // make the file self describing
     76     // TODO(lukes): we could print the command line here.  The user wouldn't be able to run it again
     77     // since there would be no runner sending continue messages, but it might be useful to debug
     78     // classpath issues.
     79     writer.println("Trial Number: " + trialNumber);
     80     writer.println("Trial Id: " + trialId);
     81     writer.println("Experiment: " + experiment);
     82     writer.println();
     83   }
     84 
     85   /**
     86    * Logs a line of output to the logger.
     87    *
     88    * @param source The source of the line (e.g. 'stderr')
     89    * @param line The output
     90    */
     91   synchronized void log(String source, String line) {
     92     checkOpened();
     93     writer.printf("[%s] %s%n", source, line);
     94   }
     95 
     96   @Override public synchronized void close() {
     97     if (writer != null) {
     98       writer.close();
     99     }
    100   }
    101 
    102   /** Marks the log file so that it will not be deleted at the end of the benchmark. */
    103   synchronized void ensureFileIsSaved() {
    104     checkOpened();
    105     outputManager.persistFile(file);
    106   }
    107 
    108   /** Returns the log file path. */
    109   synchronized File trialOutputFile() {
    110     checkOpened();
    111     return file;
    112   }
    113 }
    114