/**
 * Copyright (c) 2008, http://www.snakeyaml.org
 *
 * 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.yaml.snakeyaml.events;

import java.util.Map;

import org.yaml.snakeyaml.DumperOptions.Version;
import org.yaml.snakeyaml.error.Mark;

/**
 * Marks the beginning of a document.
 * <p>
 * This event followed by the document's content and a {@link DocumentEndEvent}.
 * </p>
 */
public final class DocumentStartEvent extends Event {
    private final boolean explicit;
    private final Version version;
    private final Map<String, String> tags;

    public DocumentStartEvent(Mark startMark, Mark endMark, boolean explicit, Version version,
            Map<String, String> tags) {
        super(startMark, endMark);
        this.explicit = explicit;
        this.version = version;
        // TODO enforce not null
        // if (tags == null) {
        // throw new NullPointerException("Tags must be provided.");
        // }
        this.tags = tags;
    }

    public boolean getExplicit() {
        return explicit;
    }

    /**
     * YAML version the document conforms to.
     * 
     * @return <code>null</code>if the document has no explicit
     *         <code>%YAML</code> directive. Otherwise an array with two
     *         components, the major and minor part of the version (in this
     *         order).
     */
    public Version getVersion() {
        return version;
    }

    /**
     * Tag shorthands as defined by the <code>%TAG</code> directive.
     * 
     * @return Mapping of 'handles' to 'prefixes' (the handles include the '!'
     *         characters).
     */
    public Map<String, String> getTags() {
        return tags;
    }

    @Override
    public boolean is(Event.ID id) {
        return ID.DocumentStart == id;
    }
}
