Java Code Examples for javax.el.ELProcessor#eval()

@Test
public void testEnvironmentResolver(){
    EnvironmentImpl environment = new EnvironmentImpl();
    environment.setAttribute( "testAtr1", true );
    environment.setAttribute( "testAtr2", "33" );
    environment.setAttribute( "testAtr3", null );

    ELProcessor processor = ElUtil.initNewELProcessor( environment, null );

    boolean result = (boolean)processor.eval( "empty testAtr3 && testAtr1" );

    // this again fails: "ELResolver cannot handle a null base Object with identifier 'unknownAtr'"
    //boolean result = (boolean)processor.eval( "empty testAtr3 && testAtr1 && empty unknownAtr" );

    Assert.assertTrue( result );
}
 

@Override
public void execute( GraphEngine engine, Token token ){
    GraphInstance instance = token.getInstance();
    Environment environment = instance.getEnvironment();

    if( !environment.containsAttribute( attribute ) ){
        if( isRequired ){
            // Throw exception
            throw new WorkflowException( "Missing required attribute '" + attribute + "'" );
        }
        else{
            // Use default value
            if( defaultValue instanceof String && ElUtil.hasBrackets( (String)defaultValue ) ){
                ELProcessor processor = ElUtil.initNewELProcessor( environment, instance.getExternalId() );
                Object expressionResult = processor.eval( ElUtil.removeBrackets( (String)defaultValue ) );
                environment.setAttribute( attribute, expressionResult );
            }
            else{
                environment.setAttribute( attribute, defaultValue );
            }
        }
    }

    // Validate type of value
    Object value = environment.getAttribute( attribute );
    if( value != null && !type.isAssignableFrom( value.getClass() ) ){
        throw new WorkflowException( "The value of attribute '" + attribute
                + "' is of type " + value.getClass().getCanonicalName()
                + " whis is not assignable to the expected type " + type.getCanonicalName() );
    }

    engine.complete( token, null );
}
 

@Override
public void execute( GraphEngine engine, Token token ){
    GraphInstance instance = token.getInstance();
    Environment environment = instance.getEnvironment();
    if( value instanceof String && ElUtil.hasBrackets( (String)value ) ){
        ELProcessor processor = ElUtil.initNewELProcessor( environment, instance.getExternalId() );
        Object expressionResult = processor.eval( ElUtil.removeBrackets( (String)value ) );
        environment.setAttribute( attribute, expressionResult );
    }
    else{
        environment.setAttribute( attribute, value );
    }
    engine.complete( token, null );
}
 

@Test
public void testConditions(){
    ELProcessor processor = ElUtil.initNewELProcessor( new EnvironmentImpl(), null );

    processor.defineBean( "client", new Client( 1, "Heli Kopter" ) );
    boolean result = (boolean)processor.eval( "not empty client.name and client.id > 0" );

    Assert.assertTrue( result );
}
 

@Override
@SuppressWarnings("unchecked")
public T evaluate( GraphInstance instance ){
    if( StringUtils.isNotBlank( expression ) ){
        ELProcessor processor = ElUtil.initNewELProcessor( instance.getEnvironment(), instance.getExternalId() );
        Object expressionResult = processor.eval( ElUtil.removeBrackets( expression ) );
        return (T)expressionResult;
    }
    return null;
}
 

@Test
public void testEnvironmentResolverInstanceIdNull(){
    EnvironmentImpl environment = new EnvironmentImpl();

    ELProcessor processor = ElUtil.initNewELProcessor( environment, null );

    Long instanceId = (Long)processor.eval( "WORKFLOW_INSTANCE_ID" );
    Assert.assertEquals( null, instanceId );
}
 

@Test
public void testEnvironmentResolverInstanceId(){
    EnvironmentImpl environment = new EnvironmentImpl();

    ELProcessor processor = ElUtil.initNewELProcessor( environment, 55L );

    long instanceId = (long)processor.eval( "WORKFLOW_INSTANCE_ID" );
    Assert.assertEquals( 55, instanceId );
}
 

@Test
public void testEnvironmentResolverNull(){
    EnvironmentImpl environment = new EnvironmentImpl();
    environment.setAttribute( "testDate1", null );

    ELProcessor processor = ElUtil.initNewELProcessor( environment, null );

    // in EL, null.fieldName does not throw a nullpointer, and null in conditions always returns false
    boolean result = (boolean)processor.eval( "testDate1.time < System.currentTimeMillis()" );
    Assert.assertFalse( result );
    result = (boolean)processor.eval( "testDate1.whatever > System.currentTimeMillis()" );
    Assert.assertFalse( result );
}
 

@Test
public void test03() {
    ELProcessor processor = new ELProcessor();
    Object result = processor.eval("!false");
    Assert.assertEquals(Boolean.TRUE, result);
}
 

@Test
public void testUnaryMinus01() {
    ELProcessor processor = new ELProcessor();
    Object result = processor.eval("-null");
    Assert.assertEquals(Long.valueOf(0), result);
}
 

@Test
public void testDivide02() {
    ELProcessor processor = new ELProcessor();
    Object result = processor.eval("null / null");
    Assert.assertEquals(Long.valueOf(0), result);
}
 

@Test
public void testAdd02() {
    ELProcessor processor = new ELProcessor();
    Object result = processor.eval("null + null");
    Assert.assertEquals(Long.valueOf(0), result);
}
 

@Test
public void test01() {
    ELProcessor processor = new ELProcessor();
    Object result = processor.eval("null?1:2");
    Assert.assertEquals(Long.valueOf(2), result);
}
 

@Test
public void test04() {
    ELProcessor processor = new ELProcessor();
    Object result = processor.eval("null && null");
    Assert.assertEquals(Boolean.FALSE, result);
}
 

@Test
public void test03() {
    ELProcessor processor = new ELProcessor();
    Object result = processor.eval("null && true");
    Assert.assertEquals(Boolean.FALSE, result);
}
 

@Test
public void test01() {
    ELProcessor processor = new ELProcessor();
    Object result = processor.eval("true && true");
    Assert.assertEquals(Boolean.TRUE, result);
}
 

@Test
public void test04() {
    ELProcessor processor = new ELProcessor();
    Object result = processor.eval("null || null");
    Assert.assertEquals(Boolean.FALSE, result);
}
 

@Test
public void test03() {
    ELProcessor processor = new ELProcessor();
    Object result = processor.eval("null || true");
    Assert.assertEquals(Boolean.TRUE, result);
}
 

@Test
public void test02() {
    ELProcessor processor = new ELProcessor();
    Object result = processor.eval("true || null");
    Assert.assertEquals(Boolean.TRUE, result);
}
 

/**
 * Note that we have to use a separate {@link ELProcessor} for each evaluation
 * as the {@link OptionsELResolver} may not be reused.
 *
 * @param expression
 * @param options
 * @param configuration
 * @return the result of the expression evaluation
 */
static Object eval(String expression, Options options, Configuration configuration) {
    ELProcessorFactory elpFactory = (ELProcessorFactory) configuration
            .getPropertyValue(ELProcessorFactory.EL_PROCESSOR_FACTORY_KEY);
    ELProcessor elp = elpFactory.createELProcessor(configuration);
    elp.getELManager().addELResolver(new OptionsELResolver(options));
    return elp.eval(expression);
}