org.italiangrid.storm.webdav.fs.attrs.DefaultExtendedFileAttributesHelper.java Source code

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Here is the source code for org.italiangrid.storm.webdav.fs.attrs.DefaultExtendedFileAttributesHelper.java

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/**
 * Copyright (c) Istituto Nazionale di Fisica Nucleare, 2014.
 *
 * 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 org.italiangrid.storm.webdav.fs.attrs;

import java.io.File;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.attribute.UserDefinedFileAttributeView;
import java.util.List;

import org.springframework.util.Assert;

public class DefaultExtendedFileAttributesHelper implements ExtendedAttributesHelper {

    public static final String STORM_ADLER32_CHECKSUM_ATTR_NAME = "storm.checksum.adler32";

    public DefaultExtendedFileAttributesHelper() {

    }

    protected String getAttributeValue(UserDefinedFileAttributeView view, String attributeName) throws IOException {

        if (view.list().contains(attributeName)) {
            ByteBuffer buffer = ByteBuffer.allocateDirect(view.size(attributeName));
            view.read(attributeName, buffer);
            buffer.flip();
            return StandardCharsets.UTF_8.decode(buffer).toString();
        } else {
            return "";
        }
    }

    @Override
    public void setExtendedFileAttribute(File f, String attributeName, String attributeValue) throws IOException {

        Assert.notNull(f);
        Assert.hasText(attributeName);

        UserDefinedFileAttributeView faView = Files.getFileAttributeView(f.toPath(),
                UserDefinedFileAttributeView.class);

        if (faView == null) {
            throw new IOException("UserDefinedFileAttributeView not supported on file " + f.getAbsolutePath());
        }

        faView.write(attributeName, StandardCharsets.UTF_8.encode(attributeValue));
    }

    @Override
    public String getExtendedFileAttributeValue(File f, String attributeName) throws IOException {

        Assert.notNull(f);
        Assert.hasText(attributeName);

        UserDefinedFileAttributeView faView = Files.getFileAttributeView(f.toPath(),
                UserDefinedFileAttributeView.class);

        if (faView == null) {
            throw new IOException("UserDefinedFileAttributeView not supported on file " + f.getAbsolutePath());
        }

        return getAttributeValue(faView, attributeName);

    }

    @Override
    public List<String> getExtendedFileAttributeNames(File f) throws IOException {

        Assert.notNull(f);
        UserDefinedFileAttributeView faView = Files.getFileAttributeView(f.toPath(),
                UserDefinedFileAttributeView.class);

        if (faView == null) {
            throw new IOException("UserDefinedFileAttributeView not supported on file " + f.getAbsolutePath());
        }

        return faView.list();
    }

    @Override
    public void setChecksumAttribute(File f, String checksumValue) throws IOException {

        if (fileSupportsExtendedAttributes(f)) {
            setExtendedFileAttribute(f, STORM_ADLER32_CHECKSUM_ATTR_NAME, checksumValue);
        }

    }

    @Override
    public String getChecksumAttribute(File f) throws IOException {

        return getExtendedFileAttributeValue(f, STORM_ADLER32_CHECKSUM_ATTR_NAME);
    }

    @Override
    public boolean fileSupportsExtendedAttributes(File f) throws IOException {

        Assert.notNull(f);
        UserDefinedFileAttributeView faView = Files.getFileAttributeView(f.toPath(),
                UserDefinedFileAttributeView.class);

        return (faView != null);
    }

}