62 lines
1.2 KiB
Java
62 lines
1.2 KiB
Java
package net.filebot;
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import java.util.function.Function;
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@FunctionalInterface
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public interface Resource<R> {
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R get() throws Exception;
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default MemoizedResource<R> memoize() {
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return new MemoizedResource<R>(this);
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}
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default <T> Resource<T> transform(Function<R, T> function) {
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return new TransformedResource<R, T>(this, function);
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}
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static <T> MemoizedResource<T> lazy(Resource<T> resource) {
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return resource.memoize();
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}
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}
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class MemoizedResource<R> implements Resource<R> {
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private final Resource<R> resource;
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private R value;
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public MemoizedResource(Resource<R> resource) {
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this.resource = resource;
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}
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@Override
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public synchronized R get() throws Exception {
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if (value == null) {
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value = resource.get();
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}
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return value;
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}
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public synchronized void clear() {
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value = null;
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}
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}
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class TransformedResource<R, T> implements Resource<T> {
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private final Resource<R> resource;
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private final Function<R, T> function;
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public TransformedResource(Resource<R> resource, Function<R, T> function) {
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this.resource = resource;
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this.function = function;
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}
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@Override
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public T get() throws Exception {
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return function.apply(resource.get());
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}
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}
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