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 * 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.jsieve.commands;

import static org.apache.jsieve.Constants.COMPARATOR_PREFIX;
import static org.apache.jsieve.Constants.COMPARATOR_PREFIX_LENGTH;

import java.util.List;

import org.apache.jsieve.Argument;
import org.apache.jsieve.Arguments;
import org.apache.jsieve.Block;
import org.apache.jsieve.SieveContext;
import org.apache.jsieve.StringListArgument;
import org.apache.jsieve.exception.FeatureException;
import org.apache.jsieve.exception.LookupException;
import org.apache.jsieve.exception.SieveException;
import org.apache.jsieve.mail.MailAdapter;

/**
 * Class Require implements the Require Command as defined in RFC 3028, section
 * 3.2.
 */
public class Require extends AbstractPrologCommand {

    /**
     * Constructor for Require.
     */
    public Require() {
        super();
    }

    /**
     * <p>
     * Ensure the required feature is configured.
     * </p>
     * <p>
     * Also,
     * 
     * @see org.apache.jsieve.commands.AbstractCommand#executeBasic(MailAdapter,
     *      Arguments, Block, SieveContext)
     *      </p>
     */
    protected Object executeBasic(MailAdapter mail, Arguments arguments,
            Block block, SieveContext context) throws SieveException {
        final List<String> stringArgumentList = ((StringListArgument) arguments
                                .getArgumentList().get(0)).getList();
        for (String stringArgument: stringArgumentList) {
            validateFeature(stringArgument, mail, context);
        }
        return null;
    }

    /**
     * Method validateFeature validates the required feature is configured as
     * either a Command or a Test.
     * 
     * @param name
     * @param mail
     * @param context not nul
     * @throws FeatureException
     */
    protected void validateFeature(String name, MailAdapter mail,
            SieveContext context) throws FeatureException {
        if (name.startsWith(COMPARATOR_PREFIX)) {
            final String comparatorName = name.substring(COMPARATOR_PREFIX_LENGTH);
            if (!context.getComparatorManager().isSupported(comparatorName)) {
                throw new FeatureException("Comparator \"" + comparatorName
                        + "\" is not supported.");
            }
        } else {
            // Validate as a Command
            try {
                validateCommand(name, context);
                return;
            } catch (LookupException e) {
                // Not a command
            }
    
            // Validate as a Test
            try {
                validateTest(name, context);
            } catch (LookupException e) {
                throw new FeatureException("Feature \"" + name
                        + "\" is not supported.");
            }
        }
    }

    /**
     * Method validateCommand.
     * 
     * @param name
     * @throws LookupException
     */
    protected void validateCommand(String name, SieveContext context)
            throws LookupException {
        context.getCommandManager().getCommand(name);
    }

    /**
     * Method validateTest.
     * 
     * @param name not null
     * @param context not null
     * @throws LookupException
     */
    protected void validateTest(String name, SieveContext context)
            throws LookupException {
        context.getTestManager().getTest(name);
    }

    /**
     * @see org.apache.jsieve.commands.AbstractCommand#validateArguments(Arguments,
     *      SieveContext)
     */
    protected void validateArguments(Arguments arguments, SieveContext context)
            throws SieveException {
        List<Argument> args = arguments.getArgumentList();
        if (args.size() != 1)
            throw context.getCoordinate().syntaxException(
                    new StringBuilder("Exactly 1 argument permitted. Found ").append((int)args.size()));

        Argument argument = args.get(0);
        if (!(argument instanceof StringListArgument))
            throw context.getCoordinate().syntaxException(
                    "Expecting a string-list");
    }

}