com.datastax.data.dataset.io.schema.XMLDataSetSchemaWriter Maven / Gradle / Ivy

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package com.datastax.data.dataset.io.schema;


import com.datastax.data.dataset.*;

import java.io.*;
import java.math.BigDecimal;
import java.util.Date;
import java.util.Map;
import java.util.Set;

/**
 * Writes the schema for a {@link com.datastax.data.dataset.DataSet} out as an XML Schema.
 *
 * Canonical use:
 * 
 * Writer writer = new PrintWriter(System.out);
 * XMLDataSetSchemaWriter xmlWriter = new XMLDataSetSchemaWriter(writer);
 * xmlWriter.writeDataSet(ds);
 * 
 * You can also use the static {@link com.datastax.data.dataset.util.DataSetUtility} methods, like
 * {@link com.datastax.data.dataset.util.DataSetUtility#writeDataSetAsXml(OutputStream, DataSet)} for a one-line operation.
 */
public class XMLDataSetSchemaWriter implements DataSetSchemaWriter {
    /**
     * The PrintWriter used internally for the export, instantiated in the constructor.
     */
    private PrintWriter outputPrintWriter;
    
    /**
     * Creates a new instance of XMLDataSetSchemaWriter for a given {@link OutputStream}.
     * @param os The {@link java.io.OutputStream} to write to; must be open. Will not be closed by this class. The
     * OutputStream will be wrapped in a {@link java.io.PrintWriter} so line separation
     * will be environment-specific.
     */
    public XMLDataSetSchemaWriter(OutputStream os) {
        if ( ! ( os instanceof BufferedOutputStream)) {
            os = new BufferedOutputStream(os);
        }
        this.outputPrintWriter = new PrintWriter(new BufferedWriter(new OutputStreamWriter(os)));
    }

    /**
     * Creates a new instance of XMLDataSetSchemaWriter for a given {@link Writer}.
     * @param writer The {@link java.io.Writer} to write to; must be open. Will not be closed by this class. The
     * writer will be wrapped in a {@link java.io.PrintWriter} so line separation will be
     * environment-specific.
     */
    public XMLDataSetSchemaWriter(Writer writer) {
        if ( writer instanceof PrintWriter) {
            this.outputPrintWriter = (PrintWriter)writer;
        } else {
            if ( writer instanceof BufferedWriter) {
                writer = new BufferedWriter(writer);
            }
            
            this.outputPrintWriter = new PrintWriter(writer);
        }
    }

    public void writeDataSet(DataSet ds) throws SchemaWriterException {
        writeXmlSchema(ds, "");
        outputPrintWriter.flush();
    }

    public void writeDataSet(DataSet ds, String... tableNames) throws SchemaWriterException {
        writeXmlSchema(ds, tableNames);
        outputPrintWriter.flush();
    }
    
    /**
     * Writes the entire schema to the current {@link PrintWriter}.
     * @param ds The DataSource to write.
     * @param tableNames List of table names to write, will include their relations as well.
     */
    private void writeXmlSchema(DataSet ds, String... tableNames) {
        PrintWriter pw = this.outputPrintWriter;
        boolean allTables = ( tableNames.length == 1 && tableNames[0].length() == 0 );
        
        pw.println("");
        pw.print("");
        pw.print("\t");
        pw.println("\t\t");
        pw.println("\t\t\t");
        
        Map> tables = DataSetIOUtility.extractTableList(tableNames);
        
        for (DataTable table : ds.getTables()) {
            if (!(table instanceof DataRelationTable)) {
                String tableName = table.getName();
                if ( ! allTables && ! tables.containsKey(tableName)) continue;
                
                pw.print("\t\t\t\t");
                pw.println("\t\t\t\t\t");
                pw.println("\t\t\t\t\t\t");
                for (DataColumn col : table.getColumns()) {
                    String columnName = col.getName();
                    Set cols = tables.get(tableName);
                    if ( ! allTables && ! cols.contains(columnName)) continue;
                    
                    pw.print("\t\t\t\t\t\t\t");
                }
                pw.println("\t\t\t\t\t\t");
                pw.println("\t\t\t\t\t");
                pw.println("\t\t\t\t");
            }
        }
        pw.println("\t\t\t");
        pw.println("\t\t");
        
        pw.println("\t\t");
        pw.println("\t\t\t");
        
        //write the relations out
        for (DataRelation r : ds.getRelations()) {
            DataColumn parentCol = r.getParentColumn();
            DataColumn childCol = r.getChildColumn();
            String parentTableName = parentCol.getTable().getName();
            String childTableName = childCol.getTable().getName();
            if ( ! allTables && ! ( tables.containsKey(parentTableName) && tables.containsKey(childTableName)))  continue;
            
            Set cols = null;
            cols = tables.get(parentTableName);
            if ( ! allTables && ! cols.contains(parentCol.getName())) continue;
            cols = tables.get(childTableName);
            if ( ! allTables && ! cols.contains(childCol.getName())) continue;
            
            pw.print("\t\t\t\t");
        }
        
        //write the data relation tables out
        for (DataTable table : ds.getTables()) {
            if (table instanceof DataRelationTable) {
                DataRelationTable drt = (DataRelationTable)table;
                if ( ! allTables && ! tables.containsKey(drt.getParentTable().getName())) continue;
                
                pw.print("\t\t\t\t");
            }
        }
        
        //write the data values out
        for (DataValue value : ds.getValues()) {
            pw.print("\t\t\t\t");
        }
        
        //close the annotation section
        pw.println("\t\t\t");
        pw.println("\t\t");
        
        //close the document down
        pw.println("\t");
        pw.println("");
    }
}