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package javax.faces.validator;

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.FacesContext;

/**
 * <p><strong
 * class="changed_modified_2_0_rev_a">MethodExpressionValidator</strong>
 * 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}.</p>
 */

public class MethodExpressionValidator implements Validator, StateHolder {

    // ------------------------------------------------------ Instance Variables

    private MethodExpression methodExpression = null;

    public MethodExpressionValidator() {

        super();

    }

    /**
     * <p>Construct a {@link Validator} that contains a {@link MethodExpression}.</p>
     */
    public MethodExpressionValidator(MethodExpression methodExpression) {

        super();
        this.methodExpression = methodExpression;

    }

    // ------------------------------------------------------- Validator Methods

    /**
     * @throws NullPointerException {@inheritDoc}
     * @throws ValidatorException   {@inheritDoc}
     */
    public void validate(FacesContext context,
                         UIComponent component,
                         Object value) throws ValidatorException {

        if ((context == null) || (component == null)) {
            throw new NullPointerException();
        }
        if (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


    public Object saveState(FacesContext context) {
        if (context == null) {
            throw new NullPointerException();
        }
        Object values[] = new Object[1];
        values[0] = methodExpression;
        return (values);

    }


    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 = false;


    public boolean isTransient() {

        return (this.transientValue);

    }


    public void setTransient(boolean transientValue) {

        this.transientValue = transientValue;

    }

}
