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package org.openide.modules;

import org.openide.util.Lookup;

/**
 * Information about the set of available {@linkplain ModuleInfo modules}.
 * @since org.openide.modules 7.19
 */
public class Modules {
    /**
     * Constructor for subclasses.
     */
    protected Modules() {}
    
    /**
     * Gets the singleton set of modules.
     * An implementation of this service should be registered by the module system.
     * The fallback implementation implements {@link #ownerOf} using a linear search.
     * @return the default instance
     */
    public static Modules getDefault() {
        Modules impl = Lookup.getDefault().lookup(Modules.class);
        if (impl == null) {
            impl = new Modules();
        }
        return impl;
    }

    /* Finds a module with given code name base.
     * @param cnb the {@link ModuleInfo#getCodeNameBase() code name base} of a module
     * @return the found module or <code>null</code>, if such module is not known
     *   to the system
     * @since 7.37
     */
    public ModuleInfo findCodeNameBase(String cnb) {
        for (ModuleInfo module : Lookup.getDefault().lookupAll(ModuleInfo.class)) {
            if (cnb.equals(module.getCodeNameBase())) {
                return module;
            }
        }
        return null;
    }
    
    /**
     * Finds the module which loaded a class.
     * @param clazz a class
     * @return the owner of the class, or null if it is not owned by any module
     * @see ModuleInfo#owns
     */
    public ModuleInfo ownerOf(Class<?> clazz) {
        for (ModuleInfo module : Lookup.getDefault().lookupAll(ModuleInfo.class)) {
            if (module.owns(clazz)) {
                return module;
            }
        }
        return null;
    }
}