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Spring Framework example source code file (CharacterEditor.java)

This example Spring Framework source code file (CharacterEditor.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Spring Framework tags/keywords

bean, character, charactereditor, charactereditor, illegalargumentexception, illegalargumentexception, javabean, object, propertyeditorsupport, string, string, unicode_length, unicode_length, unicode_prefix

The Spring Framework CharacterEditor.java source code

/*
 * Copyright 2002-2008 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
 *
 *      http://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 org.springframework.util.StringUtils;

/**
 * Editor for a {@link java.lang.Character}, to populate a property
 * of type <code>Character or char from a String value.
 *
 * <p>Note that the JDK does not contain a default
 * {@link java.beans.PropertyEditor property editor} for <code>char!
 * {@link org.springframework.beans.BeanWrapperImpl} will register this
 * editor by default.
 * 
 * <p>Also supports conversion from a Unicode character sequence; e.g.
 * <code>u0041 ('A').
 *
 * @author Juergen Hoeller
 * @author Rob Harrop
 * @author Rick Evans
 * @since 1.2
 * @see java.lang.Character
 * @see org.springframework.beans.BeanWrapperImpl
 */
public class CharacterEditor extends PropertyEditorSupport {

	/**
	 * The prefix that identifies a string as being a Unicode character sequence.
	 */
	private static final String UNICODE_PREFIX = "\\u";

	/**
	 * The length of a Unicode character sequence.
	 */
	private static final int UNICODE_LENGTH = 6;


	private final boolean allowEmpty;


	/**
	 * Create a new CharacterEditor instance.
	 * <p>The "allowEmpty" parameter controls whether an empty String is
	 * to be allowed in parsing, i.e. be interpreted as the <code>null
	 * value when {@link #setAsText(String) text is being converted}. If
	 * <code>false, an {@link IllegalArgumentException} will be thrown
	 * at that time.
	 * @param allowEmpty if empty strings are to be allowed
	 */
	public CharacterEditor(boolean allowEmpty) {
		this.allowEmpty = allowEmpty;
	}


	public void setAsText(String text) throws IllegalArgumentException {
		if (this.allowEmpty && !StringUtils.hasLength(text)) {
			// Treat empty String as null value.
			setValue(null);
		}
		else if (text == null) {
			throw new IllegalArgumentException("null String cannot be converted to char type");
		}
		else if (isUnicodeCharacterSequence(text)) {
			setAsUnicode(text);
		}
		else if (text.length() != 1) {
			throw new IllegalArgumentException("String [" + text + "] with length " +
					text.length() + " cannot be converted to char type");
		}
		else {
			setValue(new Character(text.charAt(0)));
		}
	}

	public String getAsText() {
		Object value = getValue();
		return (value != null ? value.toString() : "");
	}


	private boolean isUnicodeCharacterSequence(String sequence) {
		return (sequence.startsWith(UNICODE_PREFIX) && sequence.length() == UNICODE_LENGTH);
	}

	private void setAsUnicode(String text) {
		int code = Integer.parseInt(text.substring(UNICODE_PREFIX.length()), 16);
		setValue(new Character((char) code));
	}

}

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