org.apache.sling.feature.builder.MergeHandler Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of org.apache.sling.feature Show documentation

A feature describes an OSGi system

There is a newer version: 2.0.0

Show newest version

/*
 * 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.sling.feature.builder;

import org.apache.sling.feature.Extension;
import org.apache.sling.feature.Feature;
import org.osgi.annotation.versioning.ConsumerType;

/**
 * A feature merge handler can merge a feature of a particular type.
 */
@ConsumerType
public interface MergeHandler {
    /**
     * Checks whether this merger can merge extensions with that name
     * @param extension The extension
     * @return {@code true} if merger can handle this
     */
    boolean canMerge(Extension extension);

    /**
     * Merge the source extension into the target extension.
     *
     * Only called if {@link #canMerge(Extension)} for the
     * extension returned {@code true}.
     * If the target does not yet contain this extension,
     * then the targetEx argument is {@code null}. In that case
     * the handler should the extension to the target.
     *
     * @param context Context for the handler
     * @param target The target feature
     * @param source The source feature
     * @param targetEx The target extension or {@code null} if the extension does not exist in the target.
     * @param sourceEx The source extension
     * @throws IllegalStateException If the extensions can't be merged
     */
    void merge(HandlerContext context, Feature target, Feature source, Extension targetEx, Extension sourceEx);
}