com.lithium.flow.filer.ReadOnlyFiler.java Source code

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Here is the source code for com.lithium.flow.filer.ReadOnlyFiler.java

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/*
 * Copyright 2015 Lithium Technologies, 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.lithium.flow.filer;

import static com.google.common.base.Preconditions.checkNotNull;

import java.io.IOException;
import java.io.OutputStream;

import javax.annotation.Nonnull;

import com.google.common.base.Predicate;
import com.google.common.base.Predicates;

/**
 * Decorates an instance of {@link Filer} to prevent writes.
 *
 * @author Matt Ayres
 */
public class ReadOnlyFiler extends DecoratedFiler {
    private final Predicate<Filer> predicate;

    public ReadOnlyFiler(@Nonnull Filer delegate) {
        this(delegate, Predicates.alwaysTrue());
    }

    public ReadOnlyFiler(@Nonnull Filer delegate, @Nonnull Predicate<Filer> predicate) {
        super(checkNotNull(delegate));
        this.predicate = checkNotNull(predicate);
    }

    @Override
    @Nonnull
    public OutputStream writeFile(@Nonnull String path) throws IOException {
        if (predicate.apply(this)) {
            throw new IOException("read only: " + path);
        } else {
            return super.writeFile(path);
        }
    }

    @Override
    public void setFileTime(@Nonnull String path, long time) throws IOException {
        if (predicate.apply(this)) {
            throw new IOException("read only: " + path);
        } else {
            super.setFileTime(path, time);
        }
    }

    @Override
    public void deleteFile(@Nonnull String path) throws IOException {
        if (predicate.apply(this)) {
            throw new IOException("read only: " + path);
        } else {
            super.deleteFile(path);
        }
    }

    @Override
    public void createDirs(@Nonnull String path) throws IOException {
        if (predicate.apply(this)) {
            throw new IOException("read only: " + path);
        } else {
            super.createDirs(path);
        }
    }

    @Override
    public void renameFile(@Nonnull String oldPath, @Nonnull String newPath) throws IOException {
        if (predicate.apply(this)) {
            throw new IOException("read only: " + oldPath);
        } else {
            super.renameFile(oldPath, newPath);
        }
    }
}