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   2. New interface IgniteMetrics

package

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org.apache.ignite;

public

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interface

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IgniteMetrics

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{

    <T extends Metric> T metric(T metric);

     voidvoid longMetric(String name, LongSupplier valueSupplier, @Nullable String description);
 
   LongConsumer longMetric(String name, @Nullable String description);

     voidvoid doubleMetric(String name, DoubleSupplier valueSupplier, @Nullable String description);

    DoubleConsumer doubleMetric(String name, @Nullable String description);

     voidvoid booleanMetric(String name, BooleanSupplier valueSupplier, @Nullable String description);

    Consumer<Boolean> booleanMetric(String name, @Nullable String description);

    <T> void objectMetric(String name, Class<T> valueType, Supplier<T> valueSupplier, @Nullable String description);

    <T> Consumer<T> objectMetric(String name, Class<T> valueType, @Nullable String description);

    void removeMetric(String name);

     ReadOnlyMetricRegistry registry(String name);
}

Risks and Assumptions

• Custom metrics can affect the performance. 
• Ignite doesn't store custom metrics. At least at the first phase. After node restart, the metrics require registration anew.

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