datastore.html

Geotools是一个开源的Java GIS工具包,可利用它来开发符合标准的地理信息系统。Geotools提供了OGC(Open Geospatial Consortium)规范的一个实现来作为他们的

          Retrieves a list of of the available FeatureTypes.

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<CODE>&nbsp;<A HREF="../../../org/geotools/data/FeatureSource.html" title="interface in org.geotools.data">FeatureSource</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../org/geotools/data/DataStore.html#getView(org.geotools.data.Query)">getView</A></B>(<A HREF="../../../org/geotools/data/Query.html" title="interface in org.geotools.data">Query</A>&nbsp;query)</CODE>

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Access a FeatureSource for Query providing a high-level API.
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<CODE>&nbsp;void</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../../org/geotools/data/DataStore.html#updateSchema(java.lang.String, org.geotools.feature.FeatureType)">updateSchema</A></B>(<A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A>&nbsp;typeName,
             <A HREF="../../../org/geotools/feature/FeatureType.html" title="interface in org.geotools.feature">FeatureType</A>&nbsp;featureType)</CODE>

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Used to force namespace and CS info into a persistent change.
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<B>Method Detail</B></FONT></TD>
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<A NAME="createSchema(org.geotools.feature.FeatureType)"><!-- --></A><H3>
createSchema</H3>
<PRE>
public void <B>createSchema</B>(<A HREF="../../../org/geotools/feature/FeatureType.html" title="interface in org.geotools.feature">FeatureType</A>&nbsp;featureType)
                  throws <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></PRE>
<DL>
<DD>Creates storage for a new <code>featureType</code>.

 <p>
 The provided <code>featureType</code> we be accessable by the typeName
 provided by featureType.getTypeName().
 </p>
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>featureType</CODE> - FetureType to add to DataStore
<DT><B>Throws:</B>
<DD><CODE><A HREF="http://java.sun.com/j2se/1.4/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></CODE> - If featureType cannot be created</DL>
</DD>
</DL>
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<A NAME="updateSchema(java.lang.String, org.geotools.feature.FeatureType)"><!-- --></A><H3>
updateSchema</H3>
<PRE>
public void <B>updateSchema</B>(<A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A>&nbsp;typeName,
                         <A HREF="../../../org/geotools/feature/FeatureType.html" title="interface in org.geotools.feature">FeatureType</A>&nbsp;featureType)
                  throws <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></PRE>
<DL>
<DD>Used to force namespace and CS info into a persistent change.
 <p>
 The provided featureType should completely cover the existing schema.
 All attributes should be accounted for and the typeName should match.
 </p>
 <p>
 Suggestions:
 </p>
 <ul>
 <li>Sean - don't do this</li>
 <li>Jody - Just allow changes to metadata: CS, namespace, and others</li>
 <li>James - Allow change/addition of attribtues</li>
 </ul>
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>typeName</CODE> - 
<DT><B>Throws:</B>
<DD><CODE><A HREF="http://java.sun.com/j2se/1.4/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></CODE></DL>
</DD>
</DL>
<HR>

<A NAME="getTypeNames()"><!-- --></A><H3>
getTypeNames</H3>
<PRE>
public <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A>[] <B>getTypeNames</B>()
                      throws <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></PRE>
<DL>
<DD>Retrieves a list of of the available FeatureTypes.

 <p>
 This is simply a list of the FeatureType names as aquiring the actual
 FeatureType schemas may be expensive.
 </p>

 <p>
 Warning: this list may not be unique - the types may be
 in separate namespaces.
 </p>

 <p>
 If you need to worry about such things please consider the use of
 the Catalog and CatalogEntry interface - many DataStores support this.
 getTypeNames is really a convience method for a Catalog.iterator() where
 the name of each entry is returned.
 </p>
<P>
<DD><DL>

<DT><B>Returns:</B><DD>typeNames for available FeatureTypes.
<DT><B>Throws:</B>
<DD><CODE><A HREF="http://java.sun.com/j2se/1.4/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></CODE></DL>
</DD>
</DL>
<HR>

<A NAME="getSchema(java.lang.String)"><!-- --></A><H3>
getSchema</H3>
<PRE>
public <A HREF="../../../org/geotools/feature/FeatureType.html" title="interface in org.geotools.feature">FeatureType</A> <B>getSchema</B>(<A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A>&nbsp;typeName)
                      throws <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></PRE>
<DL>
<DD>Retrieve FeatureType metadata by <code>typeName</code>.

 <p>
 Retrieves the Schema information as a FeatureType object.
 </p>
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>typeName</CODE> - typeName of requested FeatureType
<DT><B>Returns:</B><DD>FeatureType for the provided typeName
<DT><B>Throws:</B>
<DD><CODE><A HREF="http://java.sun.com/j2se/1.4/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></CODE> - If typeName cannot be found</DL>
</DD>
</DL>
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<A NAME="getView(org.geotools.data.Query)"><!-- --></A><H3>
getView</H3>
<PRE>
public <A HREF="../../../org/geotools/data/FeatureSource.html" title="interface in org.geotools.data">FeatureSource</A> <B>getView</B>(<A HREF="../../../org/geotools/data/Query.html" title="interface in org.geotools.data">Query</A>&nbsp;query)
                      throws <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A>,
                             <A HREF="../../../org/geotools/feature/SchemaException.html" title="class in org.geotools.feature">SchemaException</A></PRE>
<DL>
<DD>Access a FeatureSource for Query providing a high-level API.
 <p>
 The provided Query does not need to completely cover the existing
 schema for Query.getTypeName(). The result will mostly likely only be
 a FeatureSource and probably wont' allow write access by the
 FeatureStore method.
 </p>
 <p>
 By using Query we allow support for reprojection, in addition
 to overriding the CoordinateSystem used by the native FeatureType.
 </p>
 <p>
 We may wish to limit this method to only support Queries using
 Filter.ALL.
 </p>
 <p>
 Update - GeoServer has an elegatent implementation of this functionality
 that we could steal. GeoServerFeatureSource, GeoServerFeatureStore and
 GeoServerFeatureLocking serve as a working prototype.
 </p>
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>query</CODE> - Query.getTypeName() locates FeatureType being viewed
<DT><B>Returns:</B><DD>FeatureSource providing opperations for featureType
<DT><B>Throws:</B>
<DD><CODE><A HREF="http://java.sun.com/j2se/1.4/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></CODE> - If FeatureSource is not available
<DD><CODE><A HREF="../../../org/geotools/feature/SchemaException.html" title="class in org.geotools.feature">SchemaException</A></CODE> - If fetureType is not covered by existing schema</DL>
</DD>
</DL>
<HR>

<A NAME="getFeatureSource(java.lang.String)"><!-- --></A><H3>
getFeatureSource</H3>
<PRE>
public <A HREF="../../../org/geotools/data/FeatureSource.html" title="interface in org.geotools.data">FeatureSource</A> <B>getFeatureSource</B>(<A HREF="http://java.sun.com/j2se/1.4/docs/api/java/lang/String.html" title="class or interface in java.lang">String</A>&nbsp;typeName)
                               throws <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></PRE>
<DL>
<DD>Access a FeatureSource for typeName providing a high-level API.

 <p>
 The resulting FeatureSource may implment more functionality:
 </p>
 <pre><code>

 FeatureSource fsource = dataStore.getFeatureSource( "roads" );
 FeatureStore fstore = null;
 if( fsource instanceof FeatureLocking ){
     fstore = (FeatureStore) fs;
 }
 else {
     System.out.println("We do not have write access to roads");
 }
 </code>
 </pre>
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>typeName</CODE> - 
<DT><B>Returns:</B><DD>FeatureSource (or subclass) providing opperations for typeName
<DT><B>Throws:</B>
<DD><CODE><A HREF="http://java.sun.com/j2se/1.4/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></CODE></DL>
</DD>
</DL>
<HR>

<A NAME="getFeatureReader(org.geotools.data.Query, org.geotools.data.Transaction)"><!-- --></A><H3>
getFeatureReader</H3>
<PRE>
public <A HREF="../../../org/geotools/data/FeatureReader.html" title="interface in org.geotools.data">FeatureReader</A> <B>getFeatureReader</B>(<A HREF="../../../org/geotools/data/Query.html" title="interface in org.geotools.data">Query</A>&nbsp;query,
                                      <A HREF="../../../org/geotools/data/Transaction.html" title="interface in org.geotools.data">Transaction</A>&nbsp;transaction)
                               throws <A HREF="http://java.sun.com/j2se/1.4/docs/api/java/io/IOException.html" title="class or interface in java.io">IOException</A></PRE>
<DL>
<DD>Access a FeatureReader providing access to Feature information.

 <p>
 <b>Filter</b> is used as a low-level indication of constraints.
 (Implementations may resort to using a FilteredFeatureReader, or
 provide their own optimizations)
 </p>

 <p>
 <b>FeatureType</b> provides a template for the returned FeatureReader
 </p>

 <ul>
 <li>
 featureType.getTypeName(): used by JDBC as the table reference to query
 against. Shapefile reader may need to store a lookup to the required
 filename.
 </li>
 <li>
 featureType.getAttributeTypes(): describes the requested content. This
 may be a subset of the complete FeatureType defined by the DataStore.
 </li>
 <li>
 getType.getNamespace(): describes the requested namespace for the
 results (may be different then the one used internally)
 </li>
 </ul>

 <p>
 <b>Transaction</b> to externalize DataStore state on a per Transaction
 basis. The most common example is a JDBC datastore saving a Connection
 for use across several FeatureReader requests. Similarly a Shapefile
 reader may wish to redirect FeatureReader requests to a alternate
 filename over the course of a Transaction.
 </p>

 <p>
 <b>Notes For Implementing DataStore</b>
 </p>

 <p>
 Subclasses may need to retrieve additional attributes, beyond those
 requested by featureType.getAttributeTypes(), in order to correctly
 apply the <code>filter</code>.<br>
 These Additional <b>attribtues</b> should be not be returned by
 FeatureReader. Subclasses may use ReTypeFeatureReader to aid in