Example usage for org.apache.commons.pool2.impl EvictionPolicy evict

Introduction

In this page you can find the example usage for org.apache.commons.pool2.impl EvictionPolicy evict.

Prototype

boolean evict(EvictionConfig config, PooledObject<T> underTest, int idleCount);

Source Link

Document

This method is called to test if an idle object in the pool should be evicted or not.

Usage

From source file:JDBCPool.dbcp.demo.sourcecode.GenericObjectPool.java

/**
 * {@inheritDoc}//  www  . j  a v  a2s.co  m
 * <p>
 * Successive activations of this method examine objects in sequence,
 * cycling through objects in oldest-to-youngest order.
 */
@Override
public void evict() throws Exception {
    assertOpen();

    if (idleObjects.size() > 0) {

        PooledObject<T> underTest = null;
        EvictionPolicy<T> evictionPolicy = getEvictionPolicy();

        synchronized (evictionLock) {
            EvictionConfig evictionConfig = new EvictionConfig(getMinEvictableIdleTimeMillis(),
                    getSoftMinEvictableIdleTimeMillis(), getMinIdle());

            boolean testWhileIdle = getTestWhileIdle();

            for (int i = 0, m = getNumTests(); i < m; i++) {
                if (evictionIterator == null || !evictionIterator.hasNext()) {
                    evictionIterator = new EvictionIterator(idleObjects);
                }
                if (!evictionIterator.hasNext()) {
                    // Pool exhausted, nothing to do here
                    return;
                }

                try {
                    underTest = evictionIterator.next();
                } catch (NoSuchElementException nsee) {
                    // Object was borrowed in another thread
                    // Don't count this as an eviction test so reduce i;
                    i--;
                    evictionIterator = null;
                    continue;
                }

                if (!underTest.startEvictionTest()) {
                    // Object was borrowed in another thread
                    // Don't count this as an eviction test so reduce i;
                    i--;
                    continue;
                }

                // User provided eviction policy could throw all sorts of
                // crazy exceptions. Protect against such an exception
                // killing the eviction thread.
                boolean evict;
                try {
                    evict = evictionPolicy.evict(evictionConfig, underTest, idleObjects.size());
                } catch (Throwable t) {
                    // Slightly convoluted as SwallowedExceptionListener
                    // uses Exception rather than Throwable
                    PoolUtils.checkRethrow(t);
                    swallowException(new Exception(t));
                    // Don't evict on error conditions
                    evict = false;
                }

                if (evict) {
                    destroy(underTest);
                    destroyedByEvictorCount.incrementAndGet();
                } else {
                    if (testWhileIdle) {
                        boolean active = false;
                        try {
                            factory.activateObject(underTest);
                            active = true;
                        } catch (Exception e) {
                            destroy(underTest);
                            destroyedByEvictorCount.incrementAndGet();
                        }
                        if (active) {
                            if (!factory.validateObject(underTest)) {
                                destroy(underTest);
                                destroyedByEvictorCount.incrementAndGet();
                            } else {
                                try {
                                    factory.passivateObject(underTest);
                                } catch (Exception e) {
                                    destroy(underTest);
                                    destroyedByEvictorCount.incrementAndGet();
                                }
                            }
                        }
                    }
                    if (!underTest.endEvictionTest(idleObjects)) {
                        // TODO - May need to add code here once additional
                        // states are used
                    }
                }
            }
        }
    }
    AbandonedConfig ac = this.abandonedConfig;
    if (ac != null && ac.getRemoveAbandonedOnMaintenance()) {
        removeAbandoned(ac);
    }
}

---