Java tutorial
/* * Copyright 2000-2018 Vaadin Ltd. * * 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 com.vaadin.server; import java.io.Serializable; import java.util.regex.Matcher; import java.util.regex.Pattern; import com.vaadin.server.Sizeable.Unit; import com.vaadin.shared.util.SharedUtil; /** * A class for representing a value-unit pair. Also contains utility methods for * parsing such pairs from a string. * * @since 7.4 * @author Vaadin Ltd */ public class SizeWithUnit implements Serializable { private final float size; private final Unit unit; private static final Pattern SIZE_PATTERN = Pattern.compile(SharedUtil.SIZE_PATTERN); /** * Constructs a new SizeWithUnit object representing the pair (size, unit). * * @param size * a numeric value * @param unit * a unit */ public SizeWithUnit(float size, Unit unit) { this.size = size; this.unit = unit; } /** * Returns the numeric value stored in this object. * * @return the value of this (value, unit) pair */ public float getSize() { return size; } /** * Returns the unit stored in this object. * * @return the unit of this (value, unit) pair */ public Unit getUnit() { return unit; } /** * Returns an object whose numeric value and unit are taken from the string * s. If s does not specify a unit and defaultUnit is not null, defaultUnit * is used as the unit. If defaultUnit is null and s is a nonempty string * representing a unitless number, an exception is thrown. Null or empty * string will produce {-1,Unit#PIXELS}. * * @param s * the string to be parsed * @param defaultUnit * The unit to be used if s does not contain any unit. Use null * for no default unit. * @return an object containing the parsed value and unit */ public static SizeWithUnit parseStringSize(String s, Unit defaultUnit) { if (s == null) { return null; } s = s.trim(); if (s.isEmpty()) { return null; } float size = 0; Unit unit = null; Matcher matcher = SIZE_PATTERN.matcher(s); if (matcher.find()) { size = Float.parseFloat(matcher.group(1)); if (size < 0) { size = -1; unit = Unit.PIXELS; } else { String symbol = matcher.group(2); if ((symbol != null && !symbol.isEmpty()) || defaultUnit == null) { unit = Unit.getUnitFromSymbol(symbol); } else { unit = defaultUnit; } } } else { throw new IllegalArgumentException( "Invalid size argument: \"" + s + "\" (should match " + SIZE_PATTERN.pattern() + ")"); } return new SizeWithUnit(size, unit); } /** * Returns an object whose numeric value and unit are taken from the string * s. Null or empty string will produce {-1,Unit#PIXELS}. An exception is * thrown if s specifies a number without a unit. * * @param s * the string to be parsed * @return an object containing the parsed value and unit */ public static SizeWithUnit parseStringSize(String s) { return parseStringSize(s, null); } }