org.richfaces.el.ValueExpressionAnalayserImpl Maven / Gradle / Ivy
package org.richfaces.el;
import javax.el.ELContext;
import javax.el.ELException;
import javax.el.ValueExpression;
import javax.faces.context.FacesContext;
public class ValueExpressionAnalayserImpl implements ValueExpressionAnalayser {
private abstract static class ValueResolutionCommand {
private ValueDescriptor valueDescriptor;
public ValueDescriptor getValueDescriptor() {
return valueDescriptor;
}
void setValueDescriptor(ValueDescriptor valueDescriptor) {
this.valueDescriptor = valueDescriptor;
}
public abstract void resolve(ValueExpression expression, ELContext context);
}
private static final class GetTypeCommand extends ValueResolutionCommand {
@Override
public void resolve(ValueExpression expression, ELContext context) {
expression.getType(context);
}
}
private static final class SetValueCommand extends ValueResolutionCommand {
private Object value;
public SetValueCommand(Object value) {
super();
this.value = value;
}
@Override
public void resolve(ValueExpression expression, ELContext context) {
expression.setValue(context, value);
}
}
private void checkNotNull(FacesContext context, ValueExpression expression) {
if (context == null) {
throw new NullPointerException("facesContext");
}
if (expression == null) {
throw new NullPointerException("expression");
}
}
private void resolveValue(FacesContext context, ValueExpression initialExpression, ValueResolutionCommand command) throws ELException {
checkNotNull(context, initialExpression);
ValueExpression expression = initialExpression;
while (expression != null) {
CapturingELContext capturingContext = new CapturingELContext(context.getELContext());
command.resolve(expression, capturingContext);
if (capturingContext.hasReferenceExpression()) {
expression = capturingContext.getReferenceExpression();
} else {
ValueDescriptor result = capturingContext.getDescriptor();
if (result == null) {
throw new ELException("Cannot determine property for expression " + initialExpression.getExpressionString());
}
command.setValueDescriptor(result);
break;
}
}
}
public ValueDescriptor getPropertyDescriptor(FacesContext context, ValueExpression expression) throws ELException {
ValueResolutionCommand command = new GetTypeCommand();
resolveValue(context, expression, command);
return command.getValueDescriptor();
}
public ValueDescriptor updateValueAndGetPropertyDescriptor(FacesContext context, ValueExpression expression, Object newValue) throws ELException {
ValueResolutionCommand command = new SetValueCommand(newValue);
resolveValue(context, expression, command);
return command.getValueDescriptor();
}
}