Java tutorial
/******************************************************************************* * Copyright (c) 2000, 20007 IBM Corporation and others. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.swt.dnd; import java.net.MalformedURLException; import java.net.URL; import org.eclipse.rap.rwt.SingletonUtil; /** * The class <code>URLTransfer</code> provides a platform specific mechanism for * converting text in URL format represented as a java <code>String</code> to a * platform specific representation of the data and vice versa. The string must * contain a fully specified url. * <p> * An example of a java <code>String</code> containing a URL is shown below: * </p> * <code><pre> * String url = "http://www.eclipse.org"; * </code></pre> * * @see Transfer * @since 1.3 */ public class URLTransfer extends ByteArrayTransfer { static final String TYPE_NAME = "url"; static final int TYPE_ID = registerType(TYPE_NAME); private URLTransfer() { } /** * Returns the singleton instance of the URLTransfer class. * * @return the singleton instance of the URLTransfer class */ public static URLTransfer getInstance() { return SingletonUtil.getSessionInstance(URLTransfer.class); } /** * This implementation of <code>javaToNative</code> converts a URL represented * by a java <code>String</code> to a platform specific representation. * * @param object a java <code>String</code> containing a URL * @param transferData an empty <code>TransferData</code> object that will be * filled in on return with the platform specific format of the data * @see Transfer#nativeToJava */ public void javaToNative(Object object, TransferData transferData) { if (!checkURL(object) || !isSupportedType(transferData)) { DND.error(DND.ERROR_INVALID_DATA); } transferData.result = 1; try { transferData.data = new URL((String) object); } catch (MalformedURLException e) { transferData.result = 0; } } /** * This implementation of <code>nativeToJava</code> converts a platform * specific representation of a URL to a java <code>String</code>. * * @param transferData the platform specific representation of the data to be * converted * @return a java <code>String</code> containing a URL if the conversion was * successful; otherwise null * @see Transfer#javaToNative */ public Object nativeToJava(TransferData transferData) { if (!isSupportedType(transferData) || transferData.data == null) return null; if (transferData.result != 1) return null; return ((URL) transferData.data).toString(); } protected int[] getTypeIds() { return new int[] { TYPE_ID }; } protected String[] getTypeNames() { return new String[] { TYPE_NAME }; } boolean checkURL(Object object) { return object != null && (object instanceof String) && ((String) object).length() > 0; } protected boolean validate(Object object) { return checkURL(object); } }