net.digitalid.utility.logging.logger.FileLogger Maven / Gradle / Ivy

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package net.digitalid.utility.logging.logger;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;
import java.util.Properties;

import javax.annotation.Nonnull;

import net.digitalid.utility.annotations.method.Impure;
import net.digitalid.utility.annotations.method.Pure;
import net.digitalid.utility.annotations.ownership.Capturable;
import net.digitalid.utility.annotations.ownership.Captured;
import net.digitalid.utility.validation.annotations.file.existence.ExistentParent;
import net.digitalid.utility.validation.annotations.file.kind.Normal;
import net.digitalid.utility.validation.annotations.file.permission.Writable;
import net.digitalid.utility.validation.annotations.type.Mutable;

/**
 * This class implements a logger that logs the messages to a file.
 * 
 * Warning: Logging from different processes to the same file may fail!
 */
@Mutable
public class FileLogger extends PrintStreamLogger {
    
    /* -------------------------------------------------- Constructors -------------------------------------------------- */
    
    /**
     * Creates a file logger that logs the messages to the given file.
     * 
     * @throws FileNotFoundException if the given file cannot be opened or created.
     */
    protected FileLogger(@Captured @Nonnull @Normal @Writable @ExistentParent File file) throws FileNotFoundException {
        super(new PrintStream(new FileOutputStream(file, true)));
    }
    
    /**
     * Returns a file logger that logs the messages to the given file.
     * 
     * @throws FileNotFoundException if the given file cannot be opened or created.
     */
    @Pure
    public static @Capturable @Nonnull FileLogger with(@Captured @Nonnull @Normal @Writable @ExistentParent File file) throws FileNotFoundException {
        return new FileLogger(file);
    }
    
    /* -------------------------------------------------- File -------------------------------------------------- */
    
    /**
     * Sets the file to which the messages are logged.
     * 
     * @throws FileNotFoundException if the given file cannot be opened or created.
     */
    @Impure
    protected void setFile(@Captured @Nonnull @Normal @Writable @ExistentParent File file) throws FileNotFoundException {
        final @Nonnull PrintStream printStream = new PrintStream(new FileOutputStream(file, true));
        
        final @Nonnull Properties properties = System.getProperties();
        printStream.println();
        printStream.println(properties.getProperty("java.runtime.name") + " " + properties.getProperty("java.runtime.version"));
        printStream.println(properties.getProperty("java.vm.name") + " " + properties.getProperty("java.vm.version"));
        printStream.println(properties.getProperty("os.name") + " " + properties.getProperty("os.version") + " on " + properties.getProperty("os.arch"));
        printStream.println();
        
        setPrintStream(printStream);
    }
    
}