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The Core Camel Java DSL based router
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.camel.util.function;
import java.util.Objects;
import java.util.Optional;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Consumer;
import java.util.function.Predicate;
import java.util.function.Supplier;
public final class Suppliers {
private Suppliers() {
}
public static Supplier memorize(Supplier supplier) {
final AtomicReference valueHolder = new AtomicReference<>();
return () -> {
T supplied = valueHolder.get();
if (supplied == null) {
synchronized (valueHolder) {
supplied = valueHolder.get();
if (supplied == null) {
supplied = Objects.requireNonNull(supplier.get(), "Supplier should not return null");
valueHolder.lazySet(supplied);
}
}
}
return supplied;
};
}
public static Supplier memorize(ThrowingSupplier supplier, Consumer consumer) {
final AtomicReference valueHolder = new AtomicReference<>();
return () -> {
T supplied = valueHolder.get();
if (supplied == null) {
synchronized (valueHolder) {
supplied = valueHolder.get();
if (supplied == null) {
try {
supplied = Objects.requireNonNull(supplier.get(), "Supplier should not return null");
valueHolder.lazySet(supplied);
} catch (Exception e) {
consumer.accept(e);
}
}
}
}
return supplied;
};
}
public static Optional firstNotNull(ThrowingSupplier... suppliers) throws Exception {
T answer = null;
for (ThrowingSupplier supplier : suppliers) {
answer = supplier.get();
if (answer != null) {
break;
}
}
return Optional.ofNullable(answer);
}
public static Optional firstMatching(Predicate predicate, ThrowingSupplier... suppliers) throws Exception {
T answer = null;
for (ThrowingSupplier supplier : suppliers) {
answer = supplier.get();
if (predicate.test(answer)) {
break;
}
}
return Optional.ofNullable(answer);
}
}