package org.eclipse.aether.collection;

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 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
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 * 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
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 * Unless required by applicable law or agreed to in writing,
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import org.eclipse.aether.graph.Dependency;

Decides what dependencies to include in the dependency graph.

Note: Implementations must be stateless.

Warning: This hook is called from a hot spot and therefore implementations should pay attention to performance. Among others, implementations should provide a semantic equals() method. 
See Also:
RepositorySystemSession.getDependencySelector()
RepositorySystem.collectDependencies(RepositorySystemSession, CollectRequest)/**
 * Decides what dependencies to include in the dependency graph.
 * <p>
 * <strong>Note:</strong> Implementations must be stateless.
 * <p>
 * <em>Warning:</em> This hook is called from a hot spot and therefore implementations should pay attention to
 * performance. Among others, implementations should provide a semantic {@link Object#equals(Object) equals()} method.
 * 
 * @see org.eclipse.aether.RepositorySystemSession#getDependencySelector()
 * @see org.eclipse.aether.RepositorySystem#collectDependencies(org.eclipse.aether.RepositorySystemSession,
 *      CollectRequest)
 */
public interface DependencySelector
{

    
Decides whether the specified dependency should be included in the dependency graph.
Params:
dependency – The dependency to check, must not be null.
Returns:
false if the dependency should be excluded from the children of the current node, true otherwise./**
     * Decides whether the specified dependency should be included in the dependency graph.
     * 
     * @param dependency The dependency to check, must not be {@code null}.
     * @return {@code false} if the dependency should be excluded from the children of the current node, {@code true}
     *         otherwise.
     */
    boolean selectDependency( Dependency dependency );

    
Derives a dependency selector for the specified collection context. When calculating the child selector,
implementors are strongly advised to simply return the current instance if nothing changed to help save memory.
Params:
context – The dependency collection context, must not be null.
Returns:
The dependency selector for the target node or null if dependencies should be unconditionally included in the sub graph./**
     * Derives a dependency selector for the specified collection context. When calculating the child selector,
     * implementors are strongly advised to simply return the current instance if nothing changed to help save memory.
     * 
     * @param context The dependency collection context, must not be {@code null}.
     * @return The dependency selector for the target node or {@code null} if dependencies should be unconditionally
     *         included in the sub graph.
     */
    DependencySelector deriveChildSelector( DependencyCollectionContext context );

}