com.google.javascript.jscomp.bundle.CachedTransformer.java Source code

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Here is the source code for com.google.javascript.jscomp.bundle.CachedTransformer.java

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/*
 * Copyright 2017 The Closure Compiler Authors.
 *
 * Licensed 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 com.google.javascript.jscomp.bundle;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;

/** A Transformer that caches output from a delegate transformer. */
@GwtIncompatible
public class CachedTransformer implements Source.Transformer {

    private static final String DEFAULT_CACHE_SPEC = "maximumSize=10000";

    private final LoadingCache<Source, Source> cache;

    public CachedTransformer(Source.Transformer delegate, CacheBuilder<? super Source, ? super Source> builder) {
        this.cache = builder.build(CacheLoader.from(delegate::transform));
    }

    public CachedTransformer(Source.Transformer delegate, String spec) {
        this(delegate, CacheBuilder.from(spec));
    }

    public CachedTransformer(Source.Transformer delegate) {
        this(delegate, DEFAULT_CACHE_SPEC);
    }

    @Override
    public Source transform(Source input) {
        return cache.getUnchecked(input);
    }
}