https://github.com/spring-projects/spring-framework: Spring Beans (Spring IO)
  • Juergen Hoeller 
/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.beans.propertyeditors;

import java.beans.PropertyEditorSupport;
import java.text.DateFormat;
import java.text.ParseException;
import java.util.Date;

import org.springframework.lang.Nullable;
import org.springframework.util.StringUtils;


Property editor for java.util.Date, supporting a custom java.text.DateFormat. 
This is not meant to be used as system PropertyEditor but rather
as locale-specific date editor within custom controller code,
parsing user-entered number strings into Date properties of beans
and rendering them in the UI form.

In web MVC code, this editor will typically be registered with binder.registerCustomEditor. 
Author:Juergen Hoeller
See Also:
Since:28.04.2003
/**
 * Property editor for {@code java.util.Date},
 * supporting a custom {@code java.text.DateFormat}.
 *
 * <p>This is not meant to be used as system PropertyEditor but rather
 * as locale-specific date editor within custom controller code,
 * parsing user-entered number strings into Date properties of beans
 * and rendering them in the UI form.
 *
 * <p>In web MVC code, this editor will typically be registered with
 * {@code binder.registerCustomEditor}.
 *
 * @author Juergen Hoeller
 * @since 28.04.2003
 * @see java.util.Date
 * @see java.text.DateFormat
 * @see org.springframework.validation.DataBinder#registerCustomEditor
 */
public class CustomDateEditor extends PropertyEditorSupport {

	private final DateFormat dateFormat;

	private final boolean allowEmpty;

	private final int exactDateLength;


	
Create a new CustomDateEditor instance, using the given DateFormat
for parsing and rendering.

The "allowEmpty" parameter states if an empty String should
be allowed for parsing, i.e. get interpreted as null value.
Otherwise, an IllegalArgumentException gets thrown in that case.

Params:
  • dateFormat – the DateFormat to use for parsing and rendering
  • allowEmpty – if empty strings should be allowed
/**
	 * Create a new CustomDateEditor instance, using the given DateFormat
	 * for parsing and rendering.
	 * <p>The "allowEmpty" parameter states if an empty String should
	 * be allowed for parsing, i.e. get interpreted as null value.
	 * Otherwise, an IllegalArgumentException gets thrown in that case.
	 * @param dateFormat the DateFormat to use for parsing and rendering
	 * @param allowEmpty if empty strings should be allowed
	 */
	public CustomDateEditor(DateFormat dateFormat, boolean allowEmpty) {
		this.dateFormat = dateFormat;
		this.allowEmpty = allowEmpty;
		this.exactDateLength = -1;
	}

	
Create a new CustomDateEditor instance, using the given DateFormat
for parsing and rendering.

The "allowEmpty" parameter states if an empty String should
be allowed for parsing, i.e. get interpreted as null value.
Otherwise, an IllegalArgumentException gets thrown in that case.

The "exactDateLength" parameter states that IllegalArgumentException gets thrown if the String does not exactly match the length specified. This is useful because SimpleDateFormat does not enforce strict parsing of the year part, not even with setLenient(false). Without an "exactDateLength" specified, the "01/01/05" would get parsed to "01/01/0005". However, even with an "exactDateLength" specified, prepended zeros in the day or month part may still allow for a shorter year part, so consider this as just one more assertion that gets you closer to the intended date format. 
Params:
  • dateFormat – the DateFormat to use for parsing and rendering
  • allowEmpty – if empty strings should be allowed
  • exactDateLength – the exact expected length of the date String
/**
	 * Create a new CustomDateEditor instance, using the given DateFormat
	 * for parsing and rendering.
	 * <p>The "allowEmpty" parameter states if an empty String should
	 * be allowed for parsing, i.e. get interpreted as null value.
	 * Otherwise, an IllegalArgumentException gets thrown in that case.
	 * <p>The "exactDateLength" parameter states that IllegalArgumentException gets
	 * thrown if the String does not exactly match the length specified. This is useful
	 * because SimpleDateFormat does not enforce strict parsing of the year part,
	 * not even with {@code setLenient(false)}. Without an "exactDateLength"
	 * specified, the "01/01/05" would get parsed to "01/01/0005". However, even
	 * with an "exactDateLength" specified, prepended zeros in the day or month
	 * part may still allow for a shorter year part, so consider this as just
	 * one more assertion that gets you closer to the intended date format.
	 * @param dateFormat the DateFormat to use for parsing and rendering
	 * @param allowEmpty if empty strings should be allowed
	 * @param exactDateLength the exact expected length of the date String
	 */
	public CustomDateEditor(DateFormat dateFormat, boolean allowEmpty, int exactDateLength) {
		this.dateFormat = dateFormat;
		this.allowEmpty = allowEmpty;
		this.exactDateLength = exactDateLength;
	}


	
Parse the Date from the given text, using the specified DateFormat.

/**
	 * Parse the Date from the given text, using the specified DateFormat.
	 */
	@Override
	public void setAsText(@Nullable String text) throws IllegalArgumentException {
		if (this.allowEmpty && !StringUtils.hasText(text)) {
			// Treat empty String as null value.
			setValue(null);
		}
		else if (text != null && this.exactDateLength >= 0 && text.length() != this.exactDateLength) {
			throw new IllegalArgumentException(
					"Could not parse date: it is not exactly" + this.exactDateLength + "characters long");
		}
		else {
			try {
				setValue(this.dateFormat.parse(text));
			}
			catch (ParseException ex) {
				throw new IllegalArgumentException("Could not parse date: " + ex.getMessage(), ex);
			}
		}
	}

	
Format the Date as String, using the specified DateFormat.

/**
	 * Format the Date as String, using the specified DateFormat.
	 */
	@Override
	public String getAsText() {
		Date value = (Date) getValue();
		return (value != null ? this.dateFormat.format(value) : "");
	}

}