Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2011 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.swt.custom; import org.eclipse.swt.*; import org.eclipse.swt.graphics.*; /** * <code>StyleRange</code> defines a set of styles for a specified * range of text. * <p> * The hashCode() method in this class uses the values of the public * fields to compute the hash value. When storing instances of the * class in hashed collections, do not modify these fields after the * object has been inserted. * </p> * * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a> */ public class StyleRange extends TextStyle implements Cloneable { /** * the start offset of the range, zero-based from the document start */ public int start; /** * the length of the range */ public int length; /** * the font style of the range. It may be a combination of * SWT.NORMAL, SWT.ITALIC or SWT.BOLD * * Note: the font style is not used if the <code>font</code> attribute * is set */ public int fontStyle = SWT.NORMAL; /** * Create a new style range with no styles * * @since 3.2 */ public StyleRange() { } /** * Create a new style range from an existing text style. * * @param style the text style to copy * * @since 3.4 */ public StyleRange(TextStyle style) { super(style); } /** * Create a new style range. * * @param start start offset of the style * @param length length of the style * @param foreground foreground color of the style, null if none * @param background background color of the style, null if none */ public StyleRange(int start, int length, Color foreground, Color background) { super(null, foreground, background); this.start = start; this.length = length; } /** * Create a new style range. * * @param start start offset of the style * @param length length of the style * @param foreground foreground color of the style, null if none * @param background background color of the style, null if none * @param fontStyle font style of the style, may be SWT.NORMAL, SWT.ITALIC or SWT.BOLD */ public StyleRange(int start, int length, Color foreground, Color background, int fontStyle) { this(start, length, foreground, background); this.fontStyle = fontStyle; } /** * Compares the argument to the receiver, and returns true * if they represent the <em>same</em> object using a class * specific comparison. * * @param object the object to compare with this object * @return <code>true</code> if the object is the same as this object and <code>false</code> otherwise * * @see #hashCode() */ @Override public boolean equals(Object object) { if (object == this) return true; if (object instanceof StyleRange) { StyleRange style = (StyleRange) object; if (start != style.start) return false; if (length != style.length) return false; return similarTo(style); } return false; } /** * Returns an integer hash code for the receiver. Any two * objects that return <code>true</code> when passed to * <code>equals</code> must return the same value for this * method. * * @return the receiver's hash * * @see #equals(Object) */ @Override public int hashCode() { return super.hashCode() ^ fontStyle; } boolean isVariableHeight() { return font != null || (metrics != null && (metrics.ascent != 0 || metrics.descent != 0)) || rise != 0; } /** * Returns whether or not the receiver is unstyled (i.e., does not have any * style attributes specified). * * @return true if the receiver is unstyled, false otherwise. */ public boolean isUnstyled() { if (font != null) return false; if (rise != 0) return false; if (metrics != null) return false; if (foreground != null) return false; if (background != null) return false; if (fontStyle != SWT.NORMAL) return false; if (underline) return false; if (strikeout) return false; if (borderStyle != SWT.NONE) return false; return true; } /** * Compares the specified object to this StyleRange and answer if the two * are similar. The object must be an instance of StyleRange and have the * same field values for except for start and length. * * @param style the object to compare with this object * @return true if the objects are similar, false otherwise */ public boolean similarTo(StyleRange style) { if (!super.equals(style)) return false; if (fontStyle != style.fontStyle) return false; return true; } /** * Returns a new StyleRange with the same values as this StyleRange. * * @return a shallow copy of this StyleRange */ @Override public Object clone() { try { return super.clone(); } catch (CloneNotSupportedException e) { return null; } } /** * Returns a string containing a concise, human-readable * description of the receiver. * * @return a string representation of the StyleRange */ @Override public String toString() { StringBuilder buffer = new StringBuilder(); buffer.append("StyleRange {"); buffer.append(start); buffer.append(", "); buffer.append(length); buffer.append(", fontStyle="); switch (fontStyle) { case SWT.BOLD: buffer.append("bold"); break; case SWT.ITALIC: buffer.append("italic"); break; case SWT.BOLD | SWT.ITALIC: buffer.append("bold-italic"); break; default: buffer.append("normal"); } String str = super.toString(); int index = str.indexOf('{'); str = str.substring(index + 1); if (str.length() > 1) buffer.append(", "); buffer.append(str); return buffer.toString(); } }