com.google.gxp.compiler.fs.AbstractFileSystem.java Source code

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Here is the source code for com.google.gxp.compiler.fs.AbstractFileSystem.java

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/*
 * Copyright (C) 2008 Google Inc.
 *
 * 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.gxp.compiler.fs;

import com.google.common.collect.Lists;

import java.nio.charset.Charset;
import java.util.*;
import java.util.regex.Pattern;

/**
 * Abstract base class for typical implementations of {@code FileSystem}. This
 * is useful for implementing {@code FileSystem}s that have all of the
 * following characteristics:
 * <ul>
 * <li>use a single {@code FileStore}
 * <li>represent a filename list as a sequence of filenames separated by some
 *     delimiter which can be matched by a regular expression
 * </ul>
 */
public abstract class AbstractFileSystem implements FileSystem {
    /**
     * Returns the FileStore used by this FileSystem.
     */
    protected abstract FileStore getFileStore();

    /**
     * Returns a regular expression which matches filename list delimters.
     */
    protected abstract Pattern getFilenameListDelimiter();

    /**
     * {@inheritDoc}
     *
     * <p>This implementation simply returns a {@code FileRef} with the abstract
     * name "/" on the {@code FileStore} returned by {@link #getFileStore()}.
     */
    public final FileRef getRoot() {
        return new FileRef(getFileStore(), "/");
    }

    /**
     * {@inheritDoc}
     *
     * <p>This implementation splits {@code filenameList} using the result of
     * {@link #getFilenameListDelimiter()} and parses the resulting filenames
     * with {@link #parseFilename(String)}.
     */
    public final List<FileRef> parseFilenameList(String filenameList) {
        String[] filenames = getFilenameListDelimiter().split(filenameList, -1);
        List<FileRef> result = Lists.newArrayListWithExpectedSize(filenames.length);
        for (int i = 0; i < filenames.length; i++) {
            result.add(parseFilename(filenames[i]));
        }
        return Collections.unmodifiableList(result);
    }

    public Charset getDefaultCharset() {
        throw new UnsupportedOperationException();
    }
}