gistfile1.txt

package org.drools.ansible.rulebook.integration.api.rulesengine;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class MemoryMonitor {

    private static final Logger LOG = LoggerFactory.getLogger(MemoryMonitor.class.getName());

    private static final int DEFAULT_MEMORY_OCCUPATION_PERCENTAGE_THRESHOLD = 90;

    private final int memoryOccupationPercentageThreshold;

    private final ScheduledThreadPoolExecutor memoryMonitor = new ScheduledThreadPoolExecutor(1, r -> {
        Thread t = new Thread(r);
        t.setDaemon(true);
        return t;
    });

    MemoryMonitor(long amount, TimeUnit unit) {
        this(DEFAULT_MEMORY_OCCUPATION_PERCENTAGE_THRESHOLD, unit.toMillis(amount));
    }

    MemoryMonitor(int threshold, long period) {
        this.memoryOccupationPercentageThreshold = threshold;
        memoryMonitor.scheduleAtFixedRate(this::checkMemoryOccupation, period, period, TimeUnit.MILLISECONDS);
    }

    public void shutdown() {
        memoryMonitor.shutdown();
    }

    protected void checkMemoryOccupation() {
        System.gc();
        int memoryOccupationPercentage = (int) ((100 * (Runtime.getRuntime().maxMemory() - Runtime.getRuntime().freeMemory())) / Runtime.getRuntime().maxMemory());
        if (memoryOccupationPercentage > memoryOccupationPercentageThreshold) {
            throw new MemoryThresholdReachedException(memoryOccupationPercentageThreshold, memoryOccupationPercentage);
        } else {
            LOG.info("Memory occupation is below the threshold: {}%", memoryOccupationPercentageThreshold);
        }
    }
}

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package org.drools.ansible.rulebook.integration.api.rulesengine;

public class MemoryThresholdReachedException extends RuntimeException {

    private final int threshold;
    private final int actual;

    public MemoryThresholdReachedException(int threshold, int actual) {
        this.threshold = threshold;
        this.actual = actual;
    }

    @Override
    public String getMessage() {
        return "Memory threshold reached: " + actual + "% > " + threshold + "%";
    }
}