connectors/file/src/main/java/org/apache/edgent/connectors/file/FileWriterRetentionConfig.java

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regarding copyright ownership.  The ASF licenses this file
to you under the Apache License, Version 2.0 (the
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  http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing,
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specific language governing permissions and limitations
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*/
package org.apache.edgent.connectors.file;

/**
 * FileWriter finalized (non-active) file retention configuration control.
 * <p>
 * File removal can be any combination of:
 * <ul>
 * <li>remove a file when {@code fileCount} would be exceeded</li>
 * <li>remove a file when {@code aggregateFileSize} would be exceeded</li>
 * <li>remove a file that's older than {@code ageSec} seconds</li>
 * </ul>
 */
public class FileWriterRetentionConfig {
    private int fileCount;
    private long aggregateFileSize;
    private long ageSec;
    private long periodMsec;
    
    /** same as {@code newConfig(fileCount, 0, 0, 0)}
     * 
     * @param fileCount remove a file when {@code fileCount} would be exceeded. 0 to disable.
     * @return the retention config
     */
    public static  FileWriterRetentionConfig newFileCountBasedConfig(int fileCount) {
        if (fileCount < 1)
            throw new IllegalArgumentException("fileCount");
        return newConfig(fileCount, 0, 0, 0);
    }
    /** same as {@code newConfig(0, aggregateFileSize, 0, 0)}
     * 
     * @param aggregateFileSize remove a file when {@code aggregateFileSize} would be exceeded. 0 to disable.
     * @return the retention config
     */
    public static  FileWriterRetentionConfig newAggregateFileSizeBasedConfig(long aggregateFileSize) {
        if (aggregateFileSize < 1)
            throw new IllegalArgumentException("aggregateFileSize");
        return newConfig(0, aggregateFileSize, 0, 0);
    }
    /** same as {@code newConfig(0, 0, ageSe, periodMsecc)}
     * 
     * @param ageSec remove a file that's older than {@code ageSec} seconds.  0 to disable.
     * @param periodMsec frequency for checking for ageSec based removal. 0 to disable.]
     * @return the retention config
     */
    public static  FileWriterRetentionConfig newAgeBasedConfig(long ageSec, long periodMsec) {
        if (ageSec < 1)
            throw new IllegalArgumentException("ageSec");
        if (periodMsec < 1)
            throw new IllegalArgumentException("periodMsec");
        return newConfig(0, 0, ageSec, periodMsec);
    }
    
    /**
     * Create a new configuration.
     * 
     * @param fileCount remove a file when {@code fileCount} would be exceeded. 0 to disable.
     * @param aggregateFileSize remove a file when {@code aggregateFileSize} would be exceeded. 0 to disable.
     * @param ageSec remove a file that's older than {@code ageSec} seconds.  0 to disable.
     * @param periodMsec frequency for checking for ageSec based removal. 0 to disable.]
     * @return the retention config
     */
    public static FileWriterRetentionConfig newConfig(int fileCount, long aggregateFileSize, long ageSec, long periodMsec) {
        return new FileWriterRetentionConfig(fileCount, aggregateFileSize, ageSec, periodMsec);
    }
    
    private FileWriterRetentionConfig(int fileCount, long aggregateFileSize, long ageSec, long periodMsec) {
        if (fileCount < 0)
            throw new IllegalArgumentException("fileCount");
        if (aggregateFileSize < 0)
            throw new IllegalArgumentException("aggregateFileSize");
        if (ageSec < 0)
            throw new IllegalArgumentException("ageSec");
        if (periodMsec < 0)
            throw new IllegalArgumentException("periodMsec");
        if (fileCount==0 && aggregateFileSize==0 && (ageSec==0 || periodMsec==0))
            throw new IllegalArgumentException("no retention configuration specified");
        this.fileCount = fileCount;
        this.aggregateFileSize = aggregateFileSize;
        this.ageSec = ageSec;
        this.periodMsec = periodMsec;
    }
    
    /**
     * Get the file count configuration value.
     * @return the value
     */
    public int getFileCount() { return fileCount; }
    
    /**
     * Get the aggregate file size configuration value.
     * @return the value
     */
    public long getAggregateFileSize() { return aggregateFileSize; }
    
    /**
     * Get the file age configuration value.
     * @return the value
     */
    public long getAgeSec() { return ageSec; }
    
    /**
     * Get the time period configuration value.
     * @return the value
     */
    public long getPeriodMsec() { return periodMsec; }
    
    /**
     * Evaluate if the specified values indicate that a final file should
     * be removed.
     *
     * @param fileCount the current number of retained files
     * @param aggregateFileSize the aggregate size of all of the retained files
     * @return true if a retained file should be removed.
     */
    public boolean evaluate(int fileCount, long aggregateFileSize) {
        return (this.fileCount > 0 && fileCount > this.fileCount)
                || (this.aggregateFileSize > 0 && aggregateFileSize > this.aggregateFileSize);
    }
    
    @Override
    public String toString() {
        return String.format("fileCount:%d aggSize:%d ageSec:%d",
                getFileCount(), getAggregateFileSize(), getAgeSec());
    }
    
}