expressioncolumntest.java

来自「用applet实现很多应用小程序」· Java 代码 · 共 80 行

package test.prefuse.data.column;

import junit.framework.TestCase;
import prefuse.data.Table;
import prefuse.data.expression.ArithmeticExpression;
import prefuse.data.expression.ColumnExpression;
import prefuse.data.expression.Expression;
import prefuse.data.expression.NumericLiteral;
import prefuse.data.io.DelimitedTextTableWriter;
import prefuse.data.util.TableIterator;
import test.prefuse.TestConfig;
import test.prefuse.data.TableTest;
import test.prefuse.data.TableTestData;

public class ExpressionColumnTest extends TestCase implements TableTestData {

    Table t;
    
    protected void setUp() throws Exception {
        super.setUp();
        t = TableTest.getTestCaseTable();
    }

    protected void tearDown() throws Exception {
        super.tearDown();
        t = null;
    }
    
    public void testDerivedColumn() {
        String AVG = "average";
        
        Expression fc = new ColumnExpression(HEADERS[3]);
        Expression dc = new ColumnExpression(HEADERS[4]);
        Expression l2 = new NumericLiteral(2);
        
        Expression add = new ArithmeticExpression(
                ArithmeticExpression.ADD, fc, dc);
        Expression avg = new ArithmeticExpression(
                ArithmeticExpression.DIV, add, l2);
        
        t.addColumn(AVG, avg);
        
        TableIterator it = t.iterator();
        while ( it.hasNext() ) {
            it.nextInt();
            float  f = it.getFloat(HEADERS[3]);
            double d = it.getDouble(HEADERS[4]);
            double av = (f+d)/2;
            assertTrue(av == it.getDouble(AVG));
        }
        
        int r = t.addRow();
        assertTrue(t.getDouble(r, AVG) == 0.0);
        
        t.setFloat(r, HEADERS[3], 2.0f);
        assertTrue(t.getDouble(r, AVG) == 1.0);
        
        t.setDouble(r, HEADERS[4], 3.0f);
        assertTrue(t.getDouble(r, AVG) == 2.5);
                
        if ( TestConfig.verbose() ) {
            try {
                new DelimitedTextTableWriter().writeTable(t, System.out);
            } catch ( Exception e ) { e.printStackTrace(); }
        }
        
        t.removeColumn(AVG);
        t.setDouble(0, HEADERS[4], 0);
        System.gc();
        t.setDouble(0, HEADERS[4], 0);
        
        if ( TestConfig.verbose() ) {
            try {
                new DelimitedTextTableWriter().writeTable(t, System.out);
            } catch ( Exception e ) { e.printStackTrace(); }
        }
    }

}