VFS-2.0-RC1/core/src/main/java/org/apache/commons/vfs/operations/DefaultFileOperations.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.commons.vfs.operations;

import org.apache.commons.vfs.FileSystemException;
import org.apache.commons.vfs.FileSystemManager;
import org.apache.commons.vfs.FileObject;

import java.util.List;
import java.util.ArrayList;

/**
 *
 * @author Siarhei Baidun
 * @since 0.1
 */
public class DefaultFileOperations implements FileOperations
{
    /**
     *
     */
    private final FileSystemManager fsmanager;

    /**
     *
     */
    private final FileObject fileObject;

    /**
     *
     * @param file The file.
     */
    public DefaultFileOperations(final FileObject file)
    {
        fileObject = file;

        fsmanager = file.getFileSystem().getFileSystemManager();
    }

    /**
     * @return The operation classes.
     * @throws FileSystemException If an error occurs.
     *
     */
    public Class[] getOperations() throws FileSystemException
    {

        final String scheme = fileObject.getURL().getProtocol();
        final FileOperationProvider[] providers = fsmanager
                .getOperationProviders(scheme);

        if (providers == null)
        {
            return null;
        }

        final List operations = new ArrayList();

        for (int i = 0; i < providers.length; i++)
        {
            FileOperationProvider provider = providers[i];

            provider.collectOperations(operations, fileObject);
        }

        return (Class[]) operations.toArray(new Class[] {});
    }

    /**
     * @param operationClass The Class that performs the operation.
     * @return The FileOperation.
     * @throws FileSystemException if an error occurs.
     *
     */
    public FileOperation getOperation(Class operationClass)
            throws FileSystemException
    {

        final String scheme = fileObject.getURL().getProtocol();
        final FileOperationProvider[] providers = fsmanager
                .getOperationProviders(scheme);

        if (providers == null)
        {
            throw new FileSystemException(
                    "vfs.provider/operation-not-supported.error", operationClass);
        }

        FileOperation resultOperation = null;

        for (int i = 0; i < providers.length; i++)
        {
            FileOperationProvider provider = providers[i];

            resultOperation = provider.getOperation(fileObject, operationClass);

            if (resultOperation != null)
            {
                break;
            }
        }

        if (resultOperation == null)
        {
            throw new FileSystemException(
                    "vfs.provider/operation-not-supported.error", operationClass);
        }

        return resultOperation;
    }

    /**
     * @param operationClass the operation's class.
     * @return true if the operation of specified class is supported for current
     *         FileObject and false otherwise.
     *
     * @throws FileSystemException if an error occurs.
     *
     */
    public boolean hasOperation(Class operationClass) throws FileSystemException
    {
        Class[] operations = getOperations();
        if (operations == null)
        {
            return false;
        }

        for (int i = 0; i < operations.length; i++)
        {
            Class operation = operations[i];
            if (operationClass.isAssignableFrom(operation))
            {
                return true;
            }
        }
        return false;
    }
}