More HPSF documentation
git-svn-id: https://svn.apache.org/repos/asf/jakarta/poi/trunk@353330 13f79535-47bb-0310-9956-ffa450edef68
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Rainer Klute
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@ -11,7 +11,7 @@
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</authors>
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</header>
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<body>
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<section><title>How To Use the HPSF APIs</title>
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<section title="How To Use the HPSF API">
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<p>This HOW-TO is organized in four sections. You should read them
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sequentially because the later sections build upon the earlier ones.</p>
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@ -51,7 +51,7 @@
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<anchor id="sec1"/>
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<section><title>Reading Standard Properties</title>
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<section title="Reading Standard Properties">
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<note>This section explains how to read
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the most important standard properties of a Microsoft Office
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@ -94,8 +94,8 @@
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<p>Sounds easy, doesn't it? Here are the steps in detail.</p>
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<section><title>Open the document \005SummaryInformation in the root of the
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POI filesystem</title>
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<section title="Open the document \005SummaryInformation in the root of the
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POI filesystem">
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<p>An application that wants to open a document in a POI filesystem
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(POIFS) proceeds as shown by the following code fragment. (The full
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@ -230,7 +230,8 @@ else
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</section>
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<anchor id="sec2"/>
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<section><title>Additional Standard Properties, Exceptions And Embedded Objects</title>
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<section title="Additional Standard Properties, Exceptions And Embedded
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Objects">
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<note>This section focusses on reading additional standard properties. It
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also talks about exceptions that may be thrown when dealing with HPSF and
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@ -308,12 +309,12 @@ else
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</section>
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<anchor id="sec3"/>
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<section><title>Reading Non-Standard Properties</title>
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<section title="Reading Non-Standard Properties">
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<note>This section tells how to read non-standard properties. Non-standard
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properties are application-specific ID/type/value triples.</note>
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<section><title>Overview</title>
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<section title="Overview">
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<p>Now comes the real hardcode stuff. As mentioned above,
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<code>SummaryInformation</code> and
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<code>DocumentSummaryInformation</code> are just special cases of the
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@ -359,7 +360,7 @@ else
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</ol>
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</section>
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<section><title>A Sample Application</title>
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<section title="A Sample Application">
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<p>Let's have a look at a sample Java application that dumps all property
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set streams contained in a POI file system. The full source code of this
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program can be found as <em>ReadCustomPropertySets.java</em> in the
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@ -397,7 +398,7 @@ import org.apache.poi.util.HexDump;</source>
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system.</p>
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</section>
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<section><title>The Property Set</title>
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<section title="The Property Set">
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<p>The listener class tries to create a <code>PropertySet</code> from each
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stream using the <code>PropertySetFactory.create()</code> method:</p>
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@ -438,7 +439,7 @@ import org.apache.poi.util.HexDump;</source>
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set stream.</p>
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</section>
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<section><title>The Sections</title>
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<section title="The Sections">
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<p>The next step is to print the number of sections followed by the
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sections themselves:</p>
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@ -493,7 +494,7 @@ for (int i2 = 0; i2 < properties.length; i2++)
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}</source>
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</section>
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<section><title>The Section's Format ID</title>
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<section title="The Section's Format ID">
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<p>The first method called on the <code>Section</code> instance is
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<code>getFormatID()</code>. As explained above, the format ID of the
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first section in a property set determines the type of the property
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@ -517,7 +518,7 @@ out(" Format ID: " + s);</source>
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<code>System.out.println()</code>.</p>
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</section>
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<section><title>The Properties</title>
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<section title="The Properties">
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<p>Before getting the properties, it is possible to find out how many
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properties are available in the section via the
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<code>Section.getPropertyCount()</code>. The sample application uses this
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@ -549,7 +550,7 @@ out(" No. of properties: " + propertyCount);</source>
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}</source>
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</section>
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<section><title>Sample Output</title>
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<section title="Sample Output">
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<p>The output of the sample program might look like the following. It
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shows the summary information and the document summary information
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property sets of a Microsoft Word document. However, unlike the first and
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@ -630,7 +631,7 @@ No property set stream: "/1Table"</source>
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</ul>
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</section>
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<section><title>Property IDs</title>
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<section title="Property IDs">
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<p>Properties in the same section are distinguished by their IDs. This is
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similar to variables in a programming language like Java, which are
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distinguished by their names. But unlike variable names, property IDs are
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@ -714,7 +715,7 @@ No property set stream: "/1Table"</source>
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</table>
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</section>
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<section><title>Property types</title>
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<section title="Property types">
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<p>A property is nothing without its value. It is stored in a property set
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stream as a sequence of bytes. You must know the property's
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<strong>type</strong> in order to properly interpret those bytes and
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@ -734,7 +735,7 @@ No property set stream: "/1Table"</source>
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the work for you.</p>
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</section>
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<section><title>Property values</title>
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<section title="Property values">
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<p>When an application wants to retrieve a property's value and calls
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<code>Property.getValue()</code>, HPSF has to interpret the bytes making
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out the value according to the property's type. The type determines how
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@ -809,7 +810,7 @@ No property set stream: "/1Table"</source>
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</section>
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<section><title>Dictionaries</title>
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<section title="Dictionaries">
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<p>The property with ID 0 has a very special meaning: It is a
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<strong>dictionary</strong> mapping property IDs to property names. We
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have seen already that the meanings of standard properties in the
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@ -832,7 +833,7 @@ No property set stream: "/1Table"</source>
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sections.</p>
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</section>
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<section><title>Codepage support</title>
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<section title="Codepage support">
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<fixme author="Rainer Klute">Improve codepage support!</fixme>
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<p>The property with ID 1 holds the number of the codepage which was used
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@ -846,14 +847,67 @@ No property set stream: "/1Table"</source>
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document from another region of the world and want to process it with
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HPSF you are in trouble - unless the creator used Unicode, of course.</p>
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</section>
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</section>
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<section><title>Further Reading</title>
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<p>There are still some aspects of HSPF left which are not covered by this
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HOW-TO. You should dig into the Javadoc API documentation to learn
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further details. Since you've struggled through this document up to this
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point, you are well prepared.</p>
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<anchor id="sec4"/>
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<section title="Writing Properties">
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<note>This section describes how to write properties.</note>
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<section title="Overview">
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<p>Writing properties is possible at a low level only at the moment. You
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have to deal with property IDs and variant types to write
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properties. There are no convenient classes or convenient methods for
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dealing with summary information and document summary information streams
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yet. If you have not already done so, you should read <link
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href="#sec3">section 3</link> to understand the following.</p>
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<p>HPSF's writing capabilities come with the classes
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<code>MutablePropertySet</code>, <code>MutableSection</code>, and
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<code>MutableProperty</code> and some helper classes. The "mutable"
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classes extend their superclasses <code>PropertySet</code>,
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<code>Section</code>, and <code>Property</code> and provide "set" and
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"write" methods.</p>
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<p>When you are going to write a property set stream your application has
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to perform the following steps:</p>
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<ol>
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<li>Create a <code>MutablePropertySet</code> instance.</li>
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<li>Get hold of a <code>MutableSection</code>. You can either retrieve
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the one that is always present in a new <code>MutablePropertySet</code>
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or create a new <code>MutableSection</code> and add it to the
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<code>MutablePropertySet</code>.
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</li>
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<li>Set any <code>Section</code> fields as you like.</li>
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<li>Create as many <code>MutableProperty</code> objects as you need. Set
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each property's ID, type, and value. Add the
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<code>MutableProperties</code> to the <code>MutableSection</code>.
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</li>
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<li>Create further <code>MutableSection</code>s if you need them.</li>
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<li>Eventually retrieve the property set as a byte stream using
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<code>MutablePropertySet.toInputStream()</code> and write it to a POIFS
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document.</li>
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</ol>
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</section>
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<section title="Low-level Writing Functions In Details">
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<fixme author="Rainer Klute">This section is still to be written.</fixme>
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</section>
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</section>
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<section title="Further Reading">
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<p>There are still some aspects of HSPF left which are not covered by this
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HOW-TO. You should dig into the Javadoc API documentation to learn
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further details. Since you've struggled through this document up to this
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point, you are well prepared.</p>
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</section>
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</section>
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</body>
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</document>
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