ColorConverter.java
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.commons.beanutils2.converters;
import java.awt.Color;
import java.util.Objects;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* {@link org.apache.commons.beanutils2.Converter} implementation that handles conversion to and from {@link Color}.
*
* <p>
* Will interpret hexadecimal colors similar to CSS engines, for example #RGB is interpreted as #RRGGBB. If using the literal hexadecimal value is desired, the
* value should be prefixed with {@code 0x} instead of {@link #HEX_COLOR_PREFIX #}.
* </p>
*
* @since 2.0.0
*/
public class ColorConverter extends AbstractConverter<Color> {
/** Prefix for hexadecimal color notation. */
private static final String HEX_COLOR_PREFIX = "#";
/** Regular expression matching the output of {@link Color#toString()}. */
private static final Pattern JAVA_COLOR_PATTERN = Pattern.compile("^(?:[A-Za-z\\d._]+)??\\[?(?:r=)?(\\d{1,3}),(?:g=)?(\\d{1,3}),(?:b=)?(\\d{1,3})\\]?$");
/**
* Construct a <strong>{@link Color}</strong> <em>Converter</em> that throws a {@code ConversionException} if an error occurs.
*/
public ColorConverter() {
}
/**
* Constructs a {@link org.apache.commons.beanutils2.Converter} that will return the specified default value if a conversion error occurs.
*
* @param defaultValue The default value to be returned if the value to be converted is missing or an error occurs converting the value.
*/
public ColorConverter(final Color defaultValue) {
super(defaultValue);
}
/**
* Converts a {@link Color} into a {@link String}.
*
* <p>
* Supports hexadecimal colors like #RGB, #RRGGBB, #RGBA, and #RRGGBBAA, and interprets raw color names based on the colors defined in Java, such as:
* </p>
*
* <ul>
* <li>{@link Color#BLACK}</li>
* <li>{@link Color#BLUE}</li>
* <li>{@link Color#CYAN}</li>
* <li>{@link Color#DARK_GRAY}</li>
* <li>{@link Color#GRAY}</li>
* <li>{@link Color#GREEN}</li>
* <li>{@link Color#LIGHT_GRAY}</li>
* <li>{@link Color#MAGENTA}</li>
* <li>{@link Color#ORANGE}</li>
* <li>{@link Color#PINK}</li>
* <li>{@link Color#RED}</li>
* <li>{@link Color#WHITE}</li>
* <li>{@link Color#YELLOW}</li>
* </ul>
*
* @param type Data type to which this value should be converted.
* @param value The String property value to convert.
* @return A {@link Color} which represents the compiled configuration property.
* @throws NullPointerException If the value is null.
* @throws NumberFormatException If an invalid number is provided.
*/
@Override
protected <T> T convertToType(final Class<T> type, final Object value) throws Throwable {
if (Color.class.isAssignableFrom(type)) {
final String stringValue = toString(value);
switch (toLowerCase(stringValue)) {
case "black":
return type.cast(Color.BLACK);
case "blue":
return type.cast(Color.BLUE);
case "cyan":
return type.cast(Color.CYAN);
case "darkgray":
case "darkgrey":
case "dark_gray":
case "dark_grey":
return type.cast(Color.DARK_GRAY);
case "gray":
case "grey":
return type.cast(Color.GRAY);
case "green":
return type.cast(Color.GREEN);
case "lightgray":
case "lightgrey":
case "light_gray":
case "light_grey":
return type.cast(Color.LIGHT_GRAY);
case "magenta":
return type.cast(Color.MAGENTA);
case "orange":
return type.cast(Color.ORANGE);
case "pink":
return type.cast(Color.PINK);
case "red":
return type.cast(Color.RED);
case "white":
return type.cast(Color.WHITE);
case "yellow":
return type.cast(Color.YELLOW);
default:
// Do nothing.
}
if (stringValue.startsWith(HEX_COLOR_PREFIX)) {
return type.cast(parseHexadecimalColor(stringValue));
}
if (stringValue.contains(",")) {
return type.cast(parseToStringColor(stringValue));
}
return type.cast(Color.decode(stringValue));
}
throw conversionException(type, value);
}
/**
* Gets the default type this {@code Converter} handles.
*
* @return The default type this {@code Converter} handles.
* @since 2.0.0
*/
@Override
protected Class<Color> getDefaultType() {
return Color.class;
}
/**
* Returns a {@link Color} for hexadecimal colors.
*
* @param value Hexadecimal representation of a color.
* @return The converted value.
* @throws NumberFormatException If the hexadecimal input contains non parsable characters.
*/
private Color parseHexadecimalColor(final String value) {
Objects.requireNonNull(value);
switch (value.length()) {
case 4:
return new Color(Integer.parseInt(value.substring(1, 2), 16) * 17, Integer.parseInt(value.substring(2, 3), 16) * 17,
Integer.parseInt(value.substring(3, 4), 16) * 17);
case 5:
return new Color(Integer.parseInt(value.substring(1, 2), 16) * 17, Integer.parseInt(value.substring(2, 3), 16) * 17,
Integer.parseInt(value.substring(3, 4), 16) * 17, Integer.parseInt(value.substring(4, 5), 16) * 17);
case 7:
return new Color(Integer.parseInt(value.substring(1, 3), 16), Integer.parseInt(value.substring(3, 5), 16),
Integer.parseInt(value.substring(5, 7), 16));
case 9:
return new Color(Integer.parseInt(value.substring(1, 3), 16), Integer.parseInt(value.substring(3, 5), 16),
Integer.parseInt(value.substring(5, 7), 16), Integer.parseInt(value.substring(7, 9), 16));
default:
throw new IllegalArgumentException("Value is an malformed hexadecimal color, if literal value decoding "
+ "is required, prefix with 0x instead of #, otherwise expecting 3, 4, 6, or 8 characters only.");
}
}
/**
* Parses the Color based on the result of the {@link Color#toString()} method.
*
* Accepts the following values:
* <ul>
* <li>{@code java.awt.Color[r=255,g=255,b=255]}</li>
* <li>{@code [r=255,g=255,b=255]}</li>
* <li>{@code r=255,g=255,b=255}</li>
* <li>{@code 255,255,255}</li>
* </ul>
*
* @param value A color as represented by {@link Color#toString()}.
* @return The Java friendly {@link Color} this color represents.
* @throws IllegalArgumentException If the input can't be matches by the {@link #JAVA_COLOR_PATTERN} or a {@link Color} component specified is over 255.
*/
private Color parseToStringColor(final String value) {
Objects.requireNonNull(value);
final Matcher matcher = JAVA_COLOR_PATTERN.matcher(value);
if (!matcher.matches()) {
throw new IllegalArgumentException("Invalid Color String provided. Could not parse.");
}
final int red = Integer.parseInt(matcher.group(1));
final int green = Integer.parseInt(matcher.group(2));
final int blue = Integer.parseInt(matcher.group(3));
if (red > 255 || green > 255 || blue > 255) {
throw new IllegalArgumentException("Color component integers must be between 0 and 255.");
}
return new Color(red, green, blue);
}
}