com.codahale.metrics.LongAdderProxy Maven / Gradle / Ivy
package com.codahale.metrics;
/**
* Proxy for creating long adders depending on the runtime. By default it tries to
* the JDK's implementation and fallbacks to the internal one if the JDK doesn't provide
* any. The JDK's LongAdder and the internal one don't have a common interface, therefore
* we adapten them to {@link InternalLongAdderProvider}, which serves as a common interface for
* long adders.
*/
class LongAdderProxy {
private interface Provider {
LongAdderAdapter get();
}
/**
* To avoid NoClassDefFoundError during loading {@link LongAdderProxy}
*/
private static class JdkProvider implements Provider {
@Override
public LongAdderAdapter get() {
return new LongAdderAdapter() {
private final java.util.concurrent.atomic.LongAdder longAdder =
new java.util.concurrent.atomic.LongAdder();
@Override
public void add(long x) {
longAdder.add(x);
}
@Override
public long sum() {
return longAdder.sum();
}
@Override
public void increment() {
longAdder.increment();
}
@Override
public void decrement() {
longAdder.decrement();
}
@Override
public long sumThenReset() {
return longAdder.sumThenReset();
}
};
}
}
/**
* Backed by the internal LongAdder
*/
private static class InternalLongAdderProvider implements Provider {
@Override
public LongAdderAdapter get() {
return new LongAdderAdapter() {
private final LongAdder longAdder = new LongAdder();
@Override
public void add(long x) {
longAdder.add(x);
}
@Override
public long sum() {
return longAdder.sum();
}
@Override
public void increment() {
longAdder.increment();
}
@Override
public void decrement() {
longAdder.decrement();
}
@Override
public long sumThenReset() {
return longAdder.sumThenReset();
}
};
}
}
private static final Provider INSTANCE = getLongAdderProvider();
private static Provider getLongAdderProvider() {
try {
final JdkProvider jdkProvider = new JdkProvider();
jdkProvider.get(); // To trigger a possible `NoClassDefFoundError` exception
return jdkProvider;
} catch (Throwable e) {
return new InternalLongAdderProvider();
}
}
public static LongAdderAdapter create() {
return INSTANCE.get();
}
}