net.derquinse.common.util.zip.LoadedZipFile.java Source code

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Here is the source code for net.derquinse.common.util.zip.LoadedZipFile.java

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/*
 * Copyright (C) the original author or 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 net.derquinse.common.util.zip;

import static net.derquinse.common.util.zip.InternalPreconditions.checkLoader;

import java.io.IOException;
import java.util.Map;

import net.derquinse.common.io.MemoryByteSource;
import net.derquinse.common.io.MemoryByteSourceLoader;

import com.google.common.base.Function;
import com.google.common.collect.ForwardingMap;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Maps;
import com.google.common.util.concurrent.UncheckedExecutionException;

/**
 * Zip file loaded into memory.
 * @author Andres Rodriguez
 */
public final class LoadedZipFile extends ForwardingMap<String, MemoryByteSource> {
    /** Loader used. */
    private final MemoryByteSourceLoader loader;
    /** Contents. */
    private final ImmutableMap<String, MemoryByteSource> entryMap;

    /** Constructor. */
    LoadedZipFile(MemoryByteSourceLoader loader, Map<String, ? extends MemoryByteSource> entries) {
        this.loader = checkLoader(loader);
        this.entryMap = ImmutableMap.copyOf(entries);
    }

    @Override
    protected Map<String, MemoryByteSource> delegate() {
        return entryMap;
    }

    /**
     * Transform the entry map.
     */
    private <T> Map<String, T> transform(Function<? super MemoryByteSource, T> f) throws IOException {
        try {
            return ImmutableMap.copyOf(Maps.transformValues(entryMap, f));
        } catch (UncheckedExecutionException e) {
            Throwable t = e.getCause();
            if (t instanceof IOException) {
                throw (IOException) t;
            }
            throw e;
        }
    }

    /**
     * Compress the entries with GZIP.
     */
    public Map<String, MemoryByteSource> gzip() throws IOException {
        return transform(GZIP.gzip(loader));
    }

    /**
     * Compress the entries with GZIP. Those smaller than the original will be kept in compressed
     * form.
     */
    public Map<String, MaybeCompressed<MemoryByteSource>> maybeGzip() throws IOException {
        return transform(GZIP.maybeGzip(loader));
    }
}