formatvalidator.java

《j2ee经典实例详解》的源代码。原书无附带光盘。介绍的是一个在线银行系统的例子。绝对难得

/*
 * Copyright (c) 2005 Sun Microsystems, Inc.  All rights reserved.  U.S.
 * Government Rights - Commercial software.  Government users are subject
 * to the Sun Microsystems, Inc. standard license agreement and
 * applicable provisions of the FAR and its supplements.  Use is subject
 * to license terms.
 *
 * This distribution may include materials developed by third parties.
 * Sun, Sun Microsystems, the Sun logo, Java and J2EE are trademarks
 * or registered trademarks of Sun Microsystems, Inc. in the U.S. and
 * other countries.
 *
 * Copyright (c) 2005 Sun Microsystems, Inc. Tous droits reserves.
 *
 * Droits du gouvernement americain, utilisateurs gouvernementaux - logiciel
 * commercial. Les utilisateurs gouvernementaux sont soumis au contrat de
 * licence standard de Sun Microsystems, Inc., ainsi qu'aux dispositions
 * en vigueur de la FAR (Federal Acquisition Regulations) et des
 * supplements a celles-ci.  Distribue par des licences qui en
 * restreignent l'utilisation.
 *
 * Cette distribution peut comprendre des composants developpes par des
 * tierces parties. Sun, Sun Microsystems, le logo Sun, Java et J2EE
 * sont des marques de fabrique ou des marques deposees de Sun
 * Microsystems, Inc. aux Etats-Unis et dans d'autres pays.
 */


package validators;

import javax.faces.FactoryFinder;
import javax.faces.component.UIComponent;
import javax.faces.component.UIInput;
import javax.faces.context.FacesContext;
import javax.faces.application.FacesMessage;
import javax.faces.validator.Validator;
import javax.faces.validator.ValidatorException;
import javax.faces.component.StateHolder;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.StringTokenizer;
import javax.faces.application.ApplicationFactory;
import javax.faces.application.Application;
import util.MessageFactory;


/**
 * <p><strong>FormatValidator</strong> is a Validator that checks
 * the validity of String representation of the value of the
 * associated component against a list of specified patterns.</p>
 * <ul>
 * <li>Call getValue() to retrieve the current value of the component.
 *     If it is <code>null</code>, exit immediately.  (If null values
 *     should not be allowed, a RequiredValidator can be configured
 *     to check for this case.)</li>
 * <li><code>formatPattern</code> is a <code>|</code> separated string
 * of allowed patterns. </li>
 * <li> This validator uses the following rules to match a value against a
 * pattern.
 * <li> if the matching pattern has a "A", then corresponding character
 *      in input value should be a letter.
 * <li> if the matching pattern has a "9", then corresponding character
 *      in input value should be a number.
 * <li> if the matching pattern has a "#", then corresponding character
 *      in input value should be a number or  a letter.
 * <li> Any other character must match literally.
 * </ul> </ul>
 *
 * Validators have to be Serializable, so you can't maintain a reference to
 * a java.sql.Connection or javax.sql.DataSource inside this class in case
 * you need to hook upto the database or some other back end resource.
 * One approach would be to use JNDI-based data source lookups or do
 * this verification in the business tier.
 */
public class FormatValidator implements Validator, StateHolder {
    // ----------------------------------------------------- Manifest Constants

    /**
     * <p>The message identifier of the Message to be created if
     * the validation fails.  The message format string for this
     * message may optionally include a <code>{0}</code> placeholder, which
     * will be replaced by list of format patterns.</p>
     */
    public static final String FORMAT_INVALID_MESSAGE_ID = "FormatInvalid";
    private ArrayList formatPatternsList = null;

    // 
    // General Methods
    //

    /**
     * <code>|</code> separated String of format patterns
     * that this validator must match against.
     */
    private String formatPatterns = null;
    private boolean transientValue = false;

    //
    // Constructors and Initializers    
    //
    public FormatValidator() {
        super();
    }

    /**
     * <p>Construct a FormatValidator with the specified formatPatterns
     * String. </p>
     *
     * @param formatPatterns <code>|</code> separated String of format patterns
     *        that this validator must match against.
     *
     */
    public FormatValidator(String formatPatterns) {
        super();
        this.formatPatterns = formatPatterns;
        parseFormatPatterns();
    }

    /**
     * <p>Return the format patterns that the validator supports.
     */
    public String getFormatPatterns() {
        return (this.formatPatterns);
    }

    /**
     * <p>Set the format patterns that the validator support..</p>
     *
     * @param formatPatterns <code>|</code> separated String of format patterns
     *        that this validator must match against.
     *
     */
    public void setFormatPatterns(String formatPatterns) {
        this.formatPatterns = formatPatterns;
        parseFormatPatterns();
    }

    /**
     * Parses the <code>formatPatterns</code> into validPatterns
     * <code>ArrayList</code>. The delimiter must be "|".
     */
    public void parseFormatPatterns() {
        if ((formatPatterns == null) || (formatPatterns.length() == 0)) {
            return;
        }

        if (formatPatternsList != null) {
            // formatPatterns have been parsed already.
            return;
        } else {
            formatPatternsList = new ArrayList();
        }

        StringTokenizer st = new StringTokenizer(formatPatterns, "|");

        while (st.hasMoreTokens()) {
            String token = st.nextToken();
            formatPatternsList.add(token);
        }
    }

    // 
    // Methods from Validator
    //
    public void validate(FacesContext context, UIComponent component,
        Object toValidate) {
        boolean valid = false;
        String value = null;

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

        if (!(component instanceof UIInput)) {
            return;
        }

        if ((null == formatPatternsList) || (null == toValidate)) {
            return;
        }

        value = toValidate.toString();

        // validate the value against the list of valid patterns.
        Iterator patternIt = formatPatternsList.iterator();

        while (patternIt.hasNext()) {
            valid = isFormatValid(((String) patternIt.next()), value);

            if (valid) {
                break;
            }
        }

        if (!valid) {
            FacesMessage errMsg =
                MessageFactory.getMessage(context, FORMAT_INVALID_MESSAGE_ID,
                    (new Object[] { formatPatterns }));
            throw new ValidatorException(errMsg);
        }
    }

    /**
     * Returns true if the value matches one of the valid patterns.
     */
    protected boolean isFormatValid(String pattern, String value) {
        boolean valid = true;

        // if there is no pattern to match then value is valid
        if ((pattern == null) || (pattern.length() == 0)) {
            return true;
        }

        // if the value is null or a zero length string return false.
        if ((value == null) || (value.length() == 0)) {
            return false;
        }

        // if the length of the value is not equal to the length of the
        // pattern string then the value is not valid.
        if (value.length() != pattern.length()) {
            return false;
        }

        value = value.trim();

        // rules for matching. 
        // 1. if the matching pattern has a "A", then corresponding character
        // in the value should a letter.
        // 2. if the matching pattern has a "9", then corresponding character
        // in the value should a number
        // 3. if the matching pattern has a "#", then corresponding character
        // in the value should a number or a letter
        // 4.. any other character must match literally.
        char[] input = value.toCharArray();
        char[] fmtpattern = pattern.toCharArray();

        for (int i = 0; i < fmtpattern.length; ++i) {
            if (fmtpattern[i] == 'A') {
                if (!(Character.isLetter(input[i]))) {
                    valid = false;
                }
            } else if (fmtpattern[i] == '9') {
                if (!(Character.isDigit(input[i]))) {
                    valid = false;
                }
            } else if (fmtpattern[i] == '#') {
                if ((!(Character.isDigit(input[i]))) &&
                        (!(Character.isLetter(input[i])))) {
                    valid = false;
                }
            } else {
                if (!(fmtpattern[i] == input[i])) {
                    valid = false;
                }
            }
        }

        return valid;
    }

    public Object saveState(FacesContext context) {
        Object[] values = new Object[2];
        values[0] = formatPatterns;
        values[1] = formatPatternsList;

        return (values);
    }

    public void restoreState(FacesContext context, Object state) {
        Object[] values = (Object[]) state;
        formatPatterns = (String) values[0];
        formatPatternsList = (ArrayList) values[1];
    }

    public boolean isTransient() {
        return (this.transientValue);
    }

    public void setTransient(boolean transientValue) {
        this.transientValue = transientValue;
    }
}