1 /* 2 * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package javax.print; 27 28 import java.io.IOException; 29 30 /** 31 * Interface MultiDoc specifies the interface for an object that supplies more 32 * than one piece of print data for a Print Job. "Doc" is a short, 33 * easy-to-pronounce term that means "a piece of print data," and a "multidoc" 34 * is a group of several docs. The client passes to the Print Job an object 35 * that implements interface MultiDoc, and the Print Job calls methods on 36 * that object to obtain the print data. 37 * <P> 38 * Interface MultiDoc provides an abstraction similar to a "linked list" of 39 * docs. A multidoc object is like a node in the linked list, containing the 40 * current doc in the list and a pointer to the next node (multidoc) in the 41 * list. The Print Job can call the multidoc's {@link #getDoc() 42 * getDoc()} method to get the current doc. When it's ready to go 43 * on to the next doc, the Print Job can call the multidoc's {@link #next() 44 * next()} method to get the next multidoc, which contains the 45 * next doc. So Print Job code for accessing a multidoc might look like this: 46 * <PRE> 47 * void processMultiDoc(MultiDoc theMultiDoc) { 48 * 49 * MultiDoc current = theMultiDoc; 50 51 * while (current != null) { 52 * processDoc (current.getDoc()); 53 * current = current.next(); 54 * } 55 * } 56 * </PRE> 57 * <P> 58 * Of course, interface MultiDoc can be implemented in any way that fulfills 59 * the contract; it doesn't have to use a linked list in the implementation. 60 * <P> 61 * To get all the print data for a multidoc print job, a Print Service 62 * proxy could use either of two patterns: 63 * <OL TYPE=1> 64 * <LI> 65 * The <B>interleaved</B> pattern: Get the doc from the current multidoc. Get 66 * the print data representation object from the current doc. Get all the print 67 * data from the print data representation object. Get the next multidoc from 68 * the current multidoc, and repeat until there are no more. (The code example 69 * above uses the interleaved pattern.) 70 * 71 * <LI> 72 * The <B>all-at-once</B> pattern: Get the doc from the current multidoc, and 73 * save the doc in a list. Get the next multidoc from the current multidoc, and 74 * repeat until there are no more. Then iterate over the list of saved docs. Get 75 * the print data representation object from the current doc. Get all the print 76 * data from the print data representation object. Go to the next doc in the 77 * list, and repeat until there are no more. 78 * </OL> 79 * Now, consider a printing client that is generating print data on the fly and 80 * does not have the resources to store more than one piece of print data at a 81 * time. If the print service proxy used the all-at-once pattern to get the 82 * print data, it would pose a problem for such a client; the client would have 83 * to keep all the docs' print data around until the print service proxy comes 84 * back and asks for them, which the client is not able to do. To work with such 85 * a client, the print service proxy must use the interleaved pattern. 86 * <P> 87 * To address this problem, and to simplify the design of clients providing 88 * multiple docs to a Print Job, every Print Service proxy that supports 89 * multidoc print jobs is required to access a MultiDoc object using the 90 * interleaved pattern. That is, given a MultiDoc object, the print service 91 * proxy will call {@link #getDoc() getDoc()} one or more times 92 * until it successfully obtains the current Doc object. The print service proxy 93 * will then obtain the current doc's print data, not proceeding until all the 94 * print data is obtained or an unrecoverable error occurs. If it is able to 95 * continue, the print service proxy will then call {@link #next() 96 * next()} one or more times until it successfully obtains either 97 * the next MultiDoc object or an indication that there are no more. An 98 * implementation of interface MultiDoc can assume the print service proxy will 99 * follow this interleaved pattern; for any other pattern of usage, the MultiDoc 100 * implementation's behavior is unspecified. 101 * <P> 102 * There is no restriction on the number of client threads that may be 103 * simultaneously accessing the same multidoc. Therefore, all implementations of 104 * interface MultiDoc must be designed to be multiple thread safe. In fact, a 105 * client thread could be adding docs to the end of the (conceptual) list while 106 * a Print Job thread is simultaneously obtaining docs from the beginning of the 107 * list; provided the multidoc object synchronizes the threads properly, the two 108 * threads will not interfere with each other 109 */ 110 111 public interface MultiDoc { 112 113 114 /** 115 * Obtain the current doc object. 116 * 117 * @return Current doc object. 118 * 119 * @exception IOException 120 * Thrown if a error occurred reading the document. 121 */ 122 public Doc getDoc() throws IOException; 123 124 /** 125 * Go to the multidoc object that contains the next doc object in the 126 * sequence of doc objects. 127 * 128 * @return Multidoc object containing the next doc object, or null if 129 * there are no further doc objects. 130 * 131 * @exception IOException 132 * Thrown if an error occurred locating the next document 133 */ 134 public MultiDoc next() throws IOException; 135 136 } | 1 /* 2 * Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package javax.print; 27 28 import java.io.IOException; 29 30 /** 31 * Interface {@code MultiDoc} specifies the interface for an object that 32 * supplies more than one piece of print data for a Print Job. "Doc" is a short, 33 * easy-to-pronounce term that means "a piece of print data," and a "multidoc" 34 * is a group of several docs. The client passes to the Print Job an object that 35 * implements interface {@code MultiDoc}, and the Print Job calls methods on 36 * that object to obtain the print data. 37 * <p> 38 * Interface {@code MultiDoc} provides an abstraction similar to a "linked list" 39 * of docs. A multidoc object is like a node in the linked list, containing the 40 * current doc in the list and a pointer to the next node (multidoc) in the 41 * list. The Print Job can call the multidoc's {@link #getDoc() getDoc()} method 42 * to get the current doc. When it's ready to go on to the next doc, the Print 43 * Job can call the multidoc's {@link #next() next()} method to get the next 44 * multidoc, which contains the next doc. So Print Job code for accessing a 45 * multidoc might look like this: 46 * 47 * <pre> 48 * void processMultiDoc(MultiDoc theMultiDoc) { 49 * 50 * MultiDoc current = theMultiDoc; 51 * 52 * while (current != null) { 53 * processDoc (current.getDoc()); 54 * current = current.next(); 55 * } 56 * } 57 * </pre> 58 * Of course, interface {@code MultiDoc} can be implemented in any way that 59 * fulfills the contract; it doesn't have to use a linked list in the 60 * implementation. 61 * <p> 62 * To get all the print data for a multidoc print job, a Print Service proxy 63 * could use either of two patterns: 64 * <ol type=1> 65 * <li>The <b>interleaved</b> pattern: Get the doc from the current multidoc. 66 * Get the print data representation object from the current doc. Get all the 67 * print data from the print data representation object. Get the next multidoc 68 * from the current multidoc, and repeat until there are no more. (The code 69 * example above uses the interleaved pattern.) 70 * <li>The <b>all-at-once</b> pattern: Get the doc from the current multidoc, 71 * and save the doc in a list. Get the next multidoc from the current 72 * multidoc, and repeat until there are no more. Then iterate over the list of 73 * saved docs. Get the print data representation object from the current doc. 74 * Get all the print data from the print data representation object. Go to the 75 * next doc in the list, and repeat until there are no more. 76 * </ol> 77 * Now, consider a printing client that is generating print data on the fly and 78 * does not have the resources to store more than one piece of print data at a 79 * time. If the print service proxy used the all-at-once pattern to get the 80 * print data, it would pose a problem for such a client; the client would have 81 * to keep all the docs' print data around until the print service proxy comes 82 * back and asks for them, which the client is not able to do. To work with such 83 * a client, the print service proxy must use the interleaved pattern. 84 * <p> 85 * To address this problem, and to simplify the design of clients providing 86 * multiple docs to a Print Job, every Print Service proxy that supports 87 * multidoc print jobs is required to access a {@code MultiDoc} object using the 88 * interleaved pattern. That is, given a {@code MultiDoc} object, the print 89 * service proxy will call {@link #getDoc() getDoc()} one or more times until it 90 * successfully obtains the current {@code Doc} object. The print service proxy 91 * will then obtain the current doc's print data, not proceeding until all the 92 * print data is obtained or an unrecoverable error occurs. If it is able to 93 * continue, the print service proxy will then call {@link #next() next()} one 94 * or more times until it successfully obtains either the next {@code MultiDoc} 95 * object or an indication that there are no more. An implementation of 96 * interface {@code MultiDoc} can assume the print service proxy will follow 97 * this interleaved pattern; for any other pattern of usage, the 98 * {@code MultiDoc} implementation's behavior is unspecified. 99 * <p> 100 * There is no restriction on the number of client threads that may be 101 * simultaneously accessing the same multidoc. Therefore, all implementations of 102 * interface MultiDoc must be designed to be multiple thread safe. In fact, a 103 * client thread could be adding docs to the end of the (conceptual) list while 104 * a Print Job thread is simultaneously obtaining docs from the beginning of the 105 * list; provided the multidoc object synchronizes the threads properly, the two 106 * threads will not interfere with each other. 107 */ 108 public interface MultiDoc { 109 110 /** 111 * Obtain the current doc object. 112 * 113 * @return current doc object 114 * @throws IOException if an error occurred when reading the document 115 */ 116 public Doc getDoc() throws IOException; 117 118 /** 119 * Go to the multidoc object that contains the next doc object in the 120 * sequence of doc objects. 121 * 122 * @return multidoc object containing the next doc object, or {@code null} 123 * if there are no further doc objects 124 * @throws IOException if an error occurred locating the next document 125 */ 126 public MultiDoc next() throws IOException; 127 } |