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package javax.faces.validator;
import java.util.Map;
import javax.el.ELContext;
import javax.el.ELException;
import javax.el.MethodExpression;
import javax.faces.component.StateHolder;
import javax.faces.component.UIComponent;
import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;
/**
* MethodExpressionValidator
* is a {@link Validator} that wraps a {@link MethodExpression}, and it
* performs validation by executing a method on an object identified by
* the {@link MethodExpression}.
*/
public class MethodExpressionValidator implements Validator, StateHolder {
private static final String BEANS_VALIDATION_AVAILABLE =
"javax.faces.private.BEANS_VALIDATION_AVAILABLE";
private static final String VALIDATE_EMPTY_FIELDS_PARAM_NAME =
"javax.faces.VALIDATE_EMPTY_FIELDS";
// ------------------------------------------------------ Instance Variables
private MethodExpression methodExpression = null;
private Boolean validateEmptyFields;
public MethodExpressionValidator() {
super();
}
/**
* Construct a {@link Validator} that contains a {@link MethodExpression}.
*
* @param methodExpression the expression to wrap
*/
public MethodExpressionValidator(MethodExpression methodExpression) {
super();
this.methodExpression = methodExpression;
}
// ------------------------------------------------------- Validator Methods
/**
* @throws NullPointerException {@inheritDoc}
* @throws ValidatorException {@inheritDoc}
*/
@Override
public void validate(FacesContext context,
UIComponent component,
Object value) throws ValidatorException {
if ((context == null) || (component == null)) {
throw new NullPointerException();
}
if (validateEmptyFields(context) || value != null) {
try {
ELContext elContext = context.getELContext();
methodExpression.invoke(elContext, new Object[]{context, component, value});
} catch (ELException ee) {
Throwable e = ee.getCause();
if (e instanceof ValidatorException) {
throw (ValidatorException) e;
} else {
throw ee;
}
}
}
}
// ----------------------------------------------------- StateHolder Methods
@Override
public Object saveState(FacesContext context) {
if (context == null) {
throw new NullPointerException();
}
Object values[] = new Object[1];
values[0] = methodExpression;
return (values);
}
@Override
public void restoreState(FacesContext context, Object state) {
if (context == null) {
throw new NullPointerException();
}
if (state == null) {
return;
}
Object values[] = (Object[]) state;
methodExpression = (MethodExpression) values[0];
}
private boolean transientValue;
@Override
public boolean isTransient() {
return (this.transientValue);
}
@Override
public void setTransient(boolean transientValue) {
this.transientValue = transientValue;
}
private boolean validateEmptyFields(FacesContext ctx) {
if (validateEmptyFields == null) {
ExternalContext extCtx = ctx.getExternalContext();
String val = extCtx.getInitParameter(VALIDATE_EMPTY_FIELDS_PARAM_NAME);
if (null == val) {
val = (String) extCtx.getApplicationMap().get(VALIDATE_EMPTY_FIELDS_PARAM_NAME);
}
if (val == null || "auto".equals(val)) {
validateEmptyFields = isBeansValidationAvailable(ctx);
} else {
validateEmptyFields = Boolean.valueOf(val);
}
}
return validateEmptyFields;
}
private boolean isBeansValidationAvailable(FacesContext context) {
boolean result = false;
Map appMap = context.getExternalContext().getApplicationMap();
if (appMap.containsKey(BEANS_VALIDATION_AVAILABLE)) {
result = (Boolean) appMap.get(BEANS_VALIDATION_AVAILABLE);
} else {
try {
new BeanValidator();
appMap.put(BEANS_VALIDATION_AVAILABLE, Boolean.TRUE);
result = true;
} catch (Throwable t) {
appMap.put(BEANS_VALIDATION_AVAILABLE, Boolean.FALSE);
}
}
return result;
}
}