<?xml version="1.0" encoding="UTF-8"?>
<!--
The contents of this file are subject to the terms of the Common Development
and Distribution License (the License). You may not use this file except in
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If applicable, add the following below the CDDL Header, with the fields
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The Original Software is NetBeans. The Initial Developer of the Original
Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun
Microsystems, Inc. All Rights Reserved.
-->
<!DOCTYPE api-answers PUBLIC "-//NetBeans//DTD Arch Answers//EN" "../../nbbuild/antsrc/org/netbeans/nbbuild/Arch.dtd" [
  <!ENTITY api-questions SYSTEM "../../nbbuild/antsrc/org/netbeans/nbbuild/Arch-api-questions.xml">
]>

<api-answers
  question-version="1.12"
  module="JavaHelp API"
  author="jglick@netbeans.org"
>

  &api-questions;


<!--
        <question id="arch-what">
            What is this project good for?
            <hint>
            Please provide here a few lines describing the project, 
            what problem it should solve, provide links to documentation, 
            specifications, etc.
            </hint>
        </question>
-->
    <answer id="arch-what">
        The JavaHelp integration API wraps the standard JavaHelp extension
        library. It also provides a small additional API for NetBeans modules to
        supply help sets to the system, add GUI menu items, and request that
        particular help topics be displayed.
        <api name="JavaHelpIntegrationAPI" type="export" category="official" 
        url="@TOP@/index.html" group="java"/>
    </answer>



<!--
        <question id="compat-i18n">
            Is your module correctly internationalized?
            <hint>
            Correct internationalization means that it obeys instuctions 
            at <a href="http://www.netbeans.org/devhome/docs/i18n/index.html">
            NetBeans I18N pages</a>.
            </hint>
        </question>
-->
    <answer id="compat-i18n">
        Yes.
    </answer>



<!--
        <question id="compat-standards">
            Does the module implement or define any standards? Is the 
            implementation exact or does it deviate somehow?
        </question>
-->
    <answer id="compat-standards">
        It only implements its own integration API. The JavaHelp reference
        implementation is bundled and that implements the JavaHelp API.
    </answer>



<!--
        <question id="compat-version">
            Can your module coexist with earlier and future
            versions of itself? Can you correctly read all old settings? Will future
            versions be able to read your current settings? Can you read
            or politely ignore settings stored by a future version?
            
            <hint>
            Very helpful for reading settings is to store version number
            there, so future versions can decide whether how to read/convert
            the settings and older versions can ignore the new ones.
            </hint>
        </question>
-->
    <answer id="compat-version">
        N/A
    </answer>



<!--
        <question id="dep-jre">
            Which version of JRE do you need (1.2, 1.3, 1.4, etc.)?
            <hint>
            It is expected that if your module runs on 1.x that it will run 
            on 1.x+1 if no, state that please. Also describe here cases where
            you run different code on different versions of JRE and why.
            </hint>
        </question>
-->
    <answer id="dep-jre">
        1.3
    </answer>



<!--
        <question id="dep-jrejdk">
            Do you require the JDK or is the JRE enough?
        </question>
-->
    <answer id="dep-jrejdk">
        JRE
    </answer>



<!--
        <question id="dep-nb">
            What other NetBeans projects does this one depend on?
            <hint>
            If you want, describe such projects as imported API using
            the <code>&lt;api name=&quot;identification&quot; type=&quot;import or export&quot; category=&quot;stable&quot; url=&quot;where is the description&quot; /></code>
            </hint>
        </question>
-->
    <answer id="dep-nb">
        <ul>
            <li><api name="ModulesAPI" type="import" category="official" 
            url="@org-openide-modules@/overview-summary.html" group="java"/></li>
            <li><api name="UtilitiesAPI" type="import" category="official" 
            url="@org-openide-util@/overview-summary.html" group="java"/></li>
            <li><api name="ServicesAPI" type="import" category="official" 
            url="@org-openide-util@/org/openide/util/doc-files/api.html#service-lookup" group="java"/></li>
            <li><api name="NodesAPI" type="import" category="official" 
            url="@org-openide-nodes@/overview-summary.html" group="java"/></li>
            <li><api name="WindowSystemAPI" type="import" category="official" 
            url="@org-openide-windows@/overview-summary.html" group="java"/></li>
            <li><api name="ActionsAPI" type="import" category="official" 
            url="@org-openide-actions@/overview-summary.html" group="java"/></li>
        </ul>

    </answer>



<!--
        <question id="dep-non-nb">
            What other projects outside NetBeans does this one depend on?
            
            <hint>
            Some non-NetBeans projects are packaged as NetBeans modules
            (see <a href="http://libs.netbeans.org">libraries</a>) and
            it is prefered to use this approach when more modules may
            depend on such third-party library.
            </hint>
        </question>
-->
    <answer id="dep-non-nb">
        Just a JAXP-compliant SAX parser.
    </answer>



<!--
        <question id="dep-platform">
            On which platforms does your module run? Does it run in the same
            way on each?
            <hint>
            If your module is using JNI or deals with special differences of
            OSes like filesystems, etc. please describe here what they are.
            </hint>
        </question>
-->
    <answer id="dep-platform">
        Any
    </answer>



<!--
        <question id="deploy-jar">
            Do you deploy just module JAR file(s) or other files as well?
            <hint>
            If your module consists of just one module JAR file, just confirm that.
            If it uses more than one JAR, describe where they are located, how
            they refer to each other. 
            If it consist of module JAR(s) and other files, please describe
            what is their purpose, why other files are necessary. Please 
            make sure that installation/deinstallation leaves the system 
            in state as it was before installation.
            </hint>
        </question>
-->
    <answer id="deploy-jar">
        <p>
            The JavaHelp extension library (<samp>jh.jar</samp>) is included,
            currently at version 1.1.3.
        </p>
        <p>
            <strong>Note</strong> that some versions of Solaris ship with their
            own copy of this library in the location
            <samp>/usr/j2se/opt/javahelp/lib/jhall.jar</samp>. Since this JAR is
            included in the extensions path of the JRE on such machines, it would
            override the copy of <samp>jh.jar</samp> shipped with the NetBeans
            integration module. Normally this would be tolerable, but
            unfortunately the version shipped with Solaris is outdated and
            exhibits a number of serious bugs, especially in the handling of
            Japanese search text, which make the NetBeans help system unusable
            and which were fixed in subsequent official JavaHelp releases. (Note
            that search databases for JavaHelp help sets are often not cleanly
            usable in versions of JavaHelp other than the one in which they were
            built, since details of how HTML substring indices are calculated
            tend to be unstable between even minor releases.) To avoid such bugs,
            the NetBeans launcher checks for the existence of the abovementioned
            file, and if found, prepends the NetBeans <samp>jh.jar</samp> to the
            JVM's boot classpath. Other options were considered and rejected as
            unworkable.
        </p>
    </answer>



<!--
        <question id="deploy-nbm">
            Can you deploy an NBM via the Update Center?
            <hint>
            If not why?
            </hint>
        </question>
-->
    <answer id="deploy-nbm">
        Yes.
    </answer>



<!--
        <question id="deploy-packages">
            Are packages of your module made inaccessible by not declaring them
            public?
            
            <hint>
            NetBeans module system allows restriction of access rights to
            public classes of your module from other modules. This prevents
            unwanted dependencies of others on your code and should be used
            whenever possible (<a href="http://www.netbeans.org/download/apis/org/openide/doc-files/upgrade.html#3.4-public-packages">
            public packages
            </a>). 
            </hint>
        </question>
-->
    <answer id="deploy-packages">
        Yes.
    </answer>



<!--
        <question id="deploy-shared">
            Do you need to be installed in the shared location only, or in the user directory only,
            or can your module be installed anywhere?
            <hint>
            Installation location shall not matter, if it does explain why.
            Consider also whether <code>InstalledFileLocator</code> can help.
            </hint>
        </question>
-->
    <answer id="deploy-shared">
        Either.
    </answer>



<!--
        <question id="exec-classloader">
            Does your code create its own class loader(s)?
            <hint>
            A bit unusual. Please explain why and what for.
            </hint>
        </question>
-->
    <answer id="exec-classloader">
        No.
    </answer>



<!--
        <question id="exec-component">
            Is execution of your code influenced by any (string) property
            of any of your components?
            
            <hint>
            Often <code>JComponent.getClientProperty</code>, <code>Action.getValue</code>
            or <code>PropertyDescriptor.getValue</code>, etc. are used to influence
            a behaviour of some code. This of course forms an interface that should
            be documented. Also if one depends on some interface that an object
            implements (<code>component instanceof Runnable</code>) that forms an
            API as well.
            </hint>
        </question>
-->
    <answer id="exec-component">
        <ul>
            <li>
                <api type="export" group="property" name="OpenIDE-mergeIntoMaster" category="official">
                    The context and key <code>OpenIDE/mergeIntoMaster</code> can be set as an attribute on a help set
                    provided programmatically rather than with an XML file to
                    customize one attribute. Such programmatic provision is rare
                    but supported.
                </api>
            
            </li>
            <li>
                <api type="export" group="property" name="javahelp.ignore.modality" category="friend">
                     The help window through JDK 1.5.0 handles modal dialogs by reparenting the help 
                     component into a child dialog of any new modal dialog whenever it is shown, and 
                     reparenting it back into a frame whenever it is hidden.  Under certain circumstances
                     (showing two dialogs sequentially before the frame can be re-shown), it can produce
                     a race condition in the underlying java.awt.Toolkit implementation.  As a workaround,
                     callers of DialogDisplayer.getDefault().notify(DialogDescriptor) may set the system
                     property "javahelp.ignore.modality" to the String "true".  This system property will
                     be reset by notify(), and applied as a client property of the root pane of the dialog
                     to be shown.  JavaHelp will, in turn, ignore the appearance of any dialog whose root
                     pane posesses the client property "javahelp.ignore.modality" with the String value
                     "true".
                </api>
            
            </li>
        </ul>
    </answer>



<!--
        <question id="exec-introspection">
            Does your module use any kind of runtime type informations (instanceof,
            work with java.lang.Class, etc.)?
            <hint>
            Check for cases when you have an object of type A and you also
            expect it to (possibly) be of type B and do some special action. That
            should be documented. The same applies on operations in meta-level
            (Class.isInstance(...), Class.isAssignableFrom(...), etc.).
            </hint>
        </question>
-->
    <answer id="exec-introspection">
        No.
    </answer>



<!--
        <question id="exec-privateaccess">
            Are you aware of any other parts of the system calling some of 
            your methods by reflection?
            <hint>
            If so, describe the &quot;contract&quot; as an API. Likely private or friend one, but
            still API and consider rewrite of it.
            </hint>
        </question>
-->
    <answer id="exec-privateaccess">
        <samp>openide-deprecated.jar</samp> calls the public API via
        introspection to avoid a compile-time dependency.
    </answer>



<!--
        <question id="exec-process">
            Do you execute an external process from your module? How do you ensure
            that the result is the same on different platforms? Do you parse output?
            Do you depend on result code?
            <hint>
            If you feed an input, parse the output please declare that as an API.
            </hint>
        </question>
-->
    <answer id="exec-process">
        No.
    </answer>



<!--
        <question id="exec-property">
            Is execution of your code influenced by any environment or
            Java system (<code>System.getProperty</code>) property?
            
            <hint>
            If there is a property that can change the behaviour of your 
            code, somebody will likely use it. You should describe what it does 
            and the stability category of this API. You may use
            <pre>
                &lt;property name=&quot;id&quot; category=&quot;private&quot; >
                    description of the property, where it is used, what it influence, etc.
                &lt;/property>            
            </pre>
            </hint>
        </question>
-->
    <answer id="exec-property">
        No.
    </answer>



<!--
        <question id="exec-reflection">
            Does your code use Java Reflection to execute other code?
            <hint>
            This usually indicates a missing or unsufficient API in the other
            part of the system. If the other side is not aware of your dependency
            this contract can be easily broken.
            </hint>
        </question>
-->
    <answer id="exec-reflection">
        There <em>is</em> a workaround for a Java bug (#4675772)
        which almost involves reflection - manually removing entries from UI
        defaults. Without this, the module will throw exceptions when disabled
        and then re&#x00EB;nabled without a restart.
        <p/>
        The module is using reflection to access the
        <api name="ModalityExcludeAPI" category="friend" group="java" type="import">
        offered by some JDKs and tracked as Java bug (5092094) <!-- see
        http://ccc.sfbay/5092094 if you can --> allowing to exclude modal
        dialogs behaviour for certain windows - in this case the help window.
        </api>.
    </answer>



<!--
        <question id="format-clipboard">
            Which data flavors (if any) does your code read from or insert to
            the clipboard (by access to clipboard on means calling methods on <code>java.awt.datatransfer.Transferable</code>?
            
            <hint>
            Often Node's deal with clipboard by usage of <code>Node.clipboardCopy, Node.clipboardCut and Node.pasteTypes</code>.
            Check your code for overriding these methods.
            </hint>
        </question>
-->
    <answer id="format-clipboard">
        N/A
    </answer>



<!--
        <question id="format-dnd">
            Which protocols (if any) does your code understand during Drag &amp; Drop?
            <hint>
            Often Node's deal with clipboard by usage of <code>Node.drag, Node.getDropType</code>. 
            Check your code for overriding these methods. Btw. if they are not overriden, they
            by default delegate to <code>Node.clipboardCopy, Node.clipboardCut and Node.pasteTypes</code>.
            </hint>
        </question>
-->
    <answer id="format-dnd">
        N/A
    </answer>



<!--
        <question id="format-types">
            Which protocols and file formats (if any) does your module read or write on disk,
            or transmit or receive over the network?
        </question>
-->
    <answer id="format-types">
        <ul>
            <li>
                The bundled JavaHelp code reads standard help sets.
            </li>
            <li>
                There is a published XML DTD for declaring the existence of a
                help set.
            </li>
            <li>
                There is a published XML DTD for creating a menu item pointing to
                a help topic.
            </li>
            <li>
                <api group="dtd" 
                     category="friend" 
                     type="export" 
                     name="ObjectTag"
                     url="@TOP@/overview-summary.html">
                </api>
                This tag is used in HTML content to create hyperlink like label in JHContentViewer. It invokes IDE
                default HTML Browser to correctly display external links.
            </li>
        </ul>
    </answer>



<!--
        <question id="lookup-lookup">
            Does your module use <code>org.openide.util.Lookup</code>
            to find any components to communicate with? Which ones?
            
            <hint>
            Please describe the interfaces you are searching for, where 
            are defined, whether you are searching for just one or more of them,
            if the order is important, etc. Also clasify the stability of such
            API contract.
            </hint>
        </question>
-->
    <answer id="lookup-lookup">
        It searches for instances of <code>javax.help.HelpSet</code> in lookup,
        according to the API specification.
    </answer>



<!--
        <question id="lookup-register">
            Do you register anything into lookup for other code to find?
            <hint>
            Do you register using layer file or using <code>META-INF/services</code>?
            Who is supposed to find your component?
            </hint>
        </question>
-->
    <answer id="lookup-register">
        A singleton instance of <code>org.netbeans.api.javahelp.Help</code> is
        registered into lookup, according to the API specification. Modules may
        depend on its existence by requiring a token of the same name. An
        instance of a handler for the <code>nbdocs</code> URL protocol (covered
        in the specification) is also registered.
    </answer>



<!--
        <question id="lookup-remove">
            Do you remove entries of other modules from lookup?
            <hint>
            Why? Of course, that is possible, but it can be dangerous. Is the module
            your are masking resource from aware of what you are doing?
            </hint>
        </question>
-->
    <answer id="lookup-remove">
        No.
    </answer>



<!--
        <question id="perf-exit">
            Does your module run any code on exit?
        </question>
-->
    <answer id="perf-exit">
        No.
    </answer>



<!--
        <question id="perf-huge_dialogs">
            Does your module contain any dialogs or wizards with a large number of
            GUI controls such as combo boxes, lists, trees, or text areas?
        </question>
-->
    <answer id="perf-huge_dialogs">
        The JavaHelp window is fairly complex, but the module only provides the
        frame that contains it.
    </answer>



<!--
        <question id="perf-limit">
            Are there any hardcoded or practical limits in the number or size of
            elements your code can handle?
        </question>
-->
    <answer id="perf-limit">
        When displaying help, all help sets need to be parsed by JavaHelp to
        determine the ID maps. For a large number of help sets, this might
        consume too much memory and CPU to be practical. Also when displaying
        "merged" help (the normal case), all help sets need to be merged
        together, which can also be time-consuming as their number grows.
    </answer>



<!--
        <question id="perf-mem">
            How much memory does your component consume? Estimate
            with a relation to the number of windows, etc.
        </question>
-->
    <answer id="perf-mem">
        Unknown. Help sets which are not in active use are supposed to be held
        softly so they could be collected.
    </answer>



<!--
        <question id="perf-menus">
            Does your module use dynamically updated context menus, or
            context-sensitive actions with complicated enablement logic?
        </question>
-->
    <answer id="perf-menus">
        Menu items representing links to help topics are dynamically enabled or
        disabled. They are always enabled in case help sets have not yet been
        parsed, to avoid forcing a parse just to display the menu item; if
        selected at this time when there is no actual corresponding ID, they will
        do nothing. After help sets have been parsed, menu items referring to
        help topics which are actually available (the normal case) are enabled.
        In case a help topic is missing for some reason, the menu item is
        disabled.
    </answer>



<!--
        <question id="perf-progress">
            Does your module execute any long-running tasks?
            <hint>Typically they are tasks like connecting over
            network, computing huge amount of data, compilation.
            Such communication should be done asynchronously (for example
            using <code>RequestProcessor</code>), definitively it should 
            not block AWT thread.
            </hint>
        </question>
-->
    <answer id="perf-progress">
        Loading and merging help sets is done asynchronously since it can be
        slow.
    </answer>



<!--
        <question id="perf-scale">
            Which external criteria influence the performance of your
            program (size of file in editor, number of files in menu, 
            in source directory, etc.) and how well your code scales?
            Please include some estimates.
        </question>
-->
    <answer id="perf-scale">
        Size of help set XML files (the map file especially) probably impacts
        parsing speed and memory consumption. Number of distinct help sets will
        probably impact performance as well. Exact numbers unknown, but JavaHelp
        appears to be pretty slow to parse and merge help sets.
    </answer>



<!--
        <question id="perf-startup">
            Does your module run any code on startup?
        </question>
-->
    <answer id="perf-startup">
        Yes, it registers a global AWT window listener. This appears to be the
        only way to reliably tell whether a modal dialog is showing at a given
        time (and to receive notification when one is shown). There is a rather
        complex set of hacks to convert the help viewer into a nonmodal dialog
        and reparent it to an active modal dialog; otherwise it would be
        impossible to access help while a modal dialog was showing. There is an
        open request for AWT to support multiple application contexts, which
        would permit the help viewer to live in an independent context and not be
        blocked by modal dialogs used in NetBeans, but until this is fixed there
        is no known good solution to the modality problem.
    </answer>



<!--
        <question id="perf-wakeup">
            Does any piece of your code wake up periodically and do something
            even when the system is otherwise idle (no user interaction)?
        </question>
-->
    <answer id="perf-wakeup">
        No.
    </answer>



<!--
        <question id="resources-file">
            Does your module use <code>java.io.File</code> directly?
            
            <hint>
            NetBeans provide a logical wrapper over plain files called 
            <code>org.openide.filesystems.FileObject</code> that
            provides uniform access to such resources and is the prefered
            way that should be used. But of course there can be situations when
            this is not suitable.
            </hint>
        </question>
-->
    <answer id="resources-file">
        It uses <code>InstalledFileLocator</code> to implement the
        <code>nbdocs</code> URL protocol, permitting help sets or files to be
        loaded from disk files in the NetBeans installation, rather than from
        inside the module. This is necessary to make it easy for users to
        customize CSS stylesheets, for example.
    </answer>



<!--
        <question id="resources-layer">
            Does your module provide own layer? Does it create any files or
            folders in it? What it is trying to communicate by that and with which 
            components?
            
            <hint>
            NetBeans allows automatic and declarative installation of resources 
            by module layers. Module register files into appropriate places
            and other components use that information to perform their task
            (build menu, toolbar, window layout, list of templates, set of
            options, etc.). 
            </hint>
        </question>
-->
    <answer id="resources-layer">
        The layer registers the <code>Help</code> singleton, declares some XML
        DTDs and their processors, installs some menu items, etc.
    </answer>



<!--
        <question id="resources-mask">
            Does your module mask/hide/override any resources provided by other modules in
            their layers?
            
            <hint>
            If you mask a file provided by another module, you probably depend
            on that and do not want the other module to (for example) change
            the file's name. That module shall thus make that file available as an API
            of some stability category.
            </hint>
        </question>
-->
    <answer id="resources-mask">
        No. However the <code>usersguide</code> module does mask the master help
        link menu item created by this module, replacing it with a similar one
        which jumps straight to the introductory page of the main NetBeans online
        help.
    </answer>



<!--
        <question id="resources-read">
            Does your module read any resources from layers? For what purpose?
            
            <hint>
            As this is some kind of intermodule dependency, it is a kind of API.
            Please describe it and clasify according to 
            <a href="http://openide.netbeans.org/tutorial/api-design.html#categories">
            common stability categories</a>.
            </hint>
        </question>
-->
    <answer id="resources-read">
        Not directly. It uses lookup to find help sets, while providing an XML
        processor to make this easier. It provides another XML processor
        permitting modules to add menu items, but does not directly interpret
        these.
    </answer>

</api-answers>
