root / branches / Mobile_Compatible_Hito_1 / libFMap_mobile_shp_driver / src-file / org / gvsig / data / datastores / vectorial / file / shp_util / SHPUtil.java @ 22037
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package org.gvsig.data.datastores.vectorial.file.shp_util; |
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import java.io.File; |
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import org.gvsig.data.datastores.vectorial.file.shp.SHPStore; |
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import org.gvsig.data.datastores.vectorial.file.shp_inst.InstSHPStore; |
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import org.gvsig.data.datastores.vectorial.file.shp_jni.JNISHPStore; |
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import org.gvsig.data.datastores.vectorial.file.shp_mem.MemSHPStore; |
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import es.prodevelop.gvsig.mobile.fmap.driver.vect.shp.ShpReader; |
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/**
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* This utility class will contain SHP-related static methods.
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*
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* @author jldominguez
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*
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*/
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public class SHPUtil { |
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/**
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* We will not load in memory if larger than this.
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*/
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public static int MEMORY_SIZE_LIMIT = 2000000; // approx. 2 megabytes |
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/**
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* We will not instantiate in memory if larger than this.
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*/
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public static int INST_SIZE_LIMIT = 1000000; // approx. 2 megabytes |
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/**
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* JNI is expected to work well if vertices per shape is larger than this.
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*/
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public static int VERTICES_PER_SHAPE_LIMIT = 500; |
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/**
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* This method will decide which data store should be used, dependiand on the SHP and
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* DBF files metadata.
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*
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* @param shpfile the shapefile of interest
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* @return the string that identifies the data store to be used
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*/
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public static String chooseShpDataStoreName(File shpfile) { |
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File dbff = org.gvsig.data.datastores.vectorial.file.shp.utils.SHP.getDbfFile(shpfile);
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//return ShpReader.getDbfFileRowCount()
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long handler = ShpReader.openDbfFile(dbff.getAbsolutePath(), false); |
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int feat_count = ShpReader.getDbfFileRowCount(handler);
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int att_count = ShpReader.getDbfFileFieldCount(handler);
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ShpReader.closeDbfFile(handler); |
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long file_bytes = (int) shpfile.length(); |
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long total_size = file_bytes + (int) dbff.length(); |
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double est_vertices_count = file_bytes / 20.0; |
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double est_vertices_per_shape = est_vertices_count / feat_count;
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// -----------------------------------
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// Metadata:
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//
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// least relevant:
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// feat_count = number of features
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// att_count = number of attributes
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//
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// most relevant:
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// est_vertices_per_shape = estimated vertices per feature
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// total_size = size in bytes of SHP + DBF
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// -----------------------------------
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if (total_size <= INST_SIZE_LIMIT) {
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return InstSHPStore.DATASTORE_NAME;
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} else {
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if (total_size <= MEMORY_SIZE_LIMIT) {
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return MemSHPStore.DATASTORE_NAME;
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} else {
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if (est_vertices_per_shape >= VERTICES_PER_SHAPE_LIMIT) {
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return JNISHPStore.DATASTORE_NAME;
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} else {
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return SHPStore.DATASTORE_NAME;
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} |
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} |
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} |
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} |
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} |