package org.alfresco.service.license;

import java.io.InputStream;

import org.alfresco.service.NotAuditable;

/**
 * Contract for managing licenses.
 * 
 * @author davidc
 */
public interface LicenseService
{
    //Constants for return values when loading a license from an input stream
    public static final String INPUTSTREAM_SUCCESS = "success";
    public static final String INPUTSTREAM_FAIL = "fail";
    public static final String INPUTSTREAM_RELOAD_FAIL = "reload-fail";
    
    /**
     * Force license reload
     */
    public String loadLicense();
    
    /**
     * Load license from the input stream
     * @param licenseStream The input stream
     * 
     * @return confirmation if the license loaded successfully.
     */
    public String loadLicense(InputStream licenseStream);
    
    /**
     * Begin the license verification loop. Throws an exception if a new .lic file has been supplied that is invalid.
     * Will quietly make the repository read only if there is no license and the repository isn't eligible for the free
     * trial period or the license has expired.
     * 
     * @throws LicenseException
     *             if an invalid .lic file has been supplied
     */
    @NotAuditable
    public void verifyLicense() throws LicenseException;

    /**
     * Was the license known to be valid the last time it was checked?.
     * 
     * @return true if there is a valid license
     */
    public boolean isLicenseValid();

    /**
     * Get description of installed license.
     * 
     * @return license descriptor (or null, if no valid license is installed)
     */
    @NotAuditable
    public LicenseDescriptor getLicense();
    
    /**
     * Register a callback that gets called when a license changes.
     */
    public void registerOnLicenseChange(LicenseChangeHandler callback);
    
    /**
     * Informs the service it is being shutdown.
     */
    @NotAuditable
    public void shutdown();
    
    /**
     * Inteface for components wishing to know when the license has changed
     *  
     * @see #registerOnLicenseChange(LicenseChangeHandler)
     */
    public interface LicenseChangeHandler 
    {
        /**
         * Notification of a license change.
         * 
         * @param licenseDescriptor         the new license (never <tt>null</tt>)
         */
        void onLicenseChange(LicenseDescriptor licenseDescriptor);
        
        /**
         * Notification that a license have failed to validate
         */
        void onLicenseFail();
    }
}