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| 1 | +/* |
| 2 | + * Copyright 2002-2021 the original author or authors. |
| 3 | + * |
| 4 | + * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | + * you may not use this file except in compliance with the License. |
| 6 | + * You may obtain a copy of the License at |
| 7 | + * |
| 8 | + * https://www.apache.org/licenses/LICENSE-2.0 |
| 9 | + * |
| 10 | + * Unless required by applicable law or agreed to in writing, software |
| 11 | + * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | + * See the License for the specific language governing permissions and |
| 14 | + * limitations under the License. |
| 15 | + */ |
| 16 | + |
| 17 | +package org.apache.directory.server.core.avltree; |
| 18 | + |
| 19 | +import java.io.ByteArrayInputStream; |
| 20 | +import java.io.ByteArrayOutputStream; |
| 21 | +import java.io.DataInputStream; |
| 22 | +import java.io.DataOutputStream; |
| 23 | +import java.io.IOException; |
| 24 | +import java.util.Comparator; |
| 25 | + |
| 26 | +import org.apache.directory.shared.ldap.util.StringTools; |
| 27 | +import org.slf4j.Logger; |
| 28 | +import org.slf4j.LoggerFactory; |
| 29 | + |
| 30 | +/** |
| 31 | + * Class to serialize the Array data. |
| 32 | + * |
| 33 | + * @author <a href="mailto:[email protected]">Apache Directory Project</a> |
| 34 | + * @version $Rev$, $Date$ |
| 35 | + */ |
| 36 | +@SuppressWarnings("unchecked") |
| 37 | +public class ArrayMarshaller<E> implements Marshaller<ArrayTree<E>> { |
| 38 | + |
| 39 | + /** static logger */ |
| 40 | + private static final Logger LOG = LoggerFactory.getLogger(ArrayMarshaller.class); |
| 41 | + |
| 42 | + /** used for serialized form of an empty AvlTree */ |
| 43 | + private static final byte[] EMPTY_TREE = new byte[1]; |
| 44 | + |
| 45 | + /** marshaller to be used for marshalling the keys */ |
| 46 | + private Marshaller<E> keyMarshaller; |
| 47 | + |
| 48 | + /** key Comparator for the AvlTree */ |
| 49 | + private Comparator<E> comparator; |
| 50 | + |
| 51 | + /** |
| 52 | + * Creates a new instance of AvlTreeMarshaller with a custom key Marshaller. |
| 53 | + * @param comparator Comparator to be used for key comparision |
| 54 | + * @param keyMarshaller marshaller for keys |
| 55 | + */ |
| 56 | + public ArrayMarshaller(Comparator<E> comparator, Marshaller<E> keyMarshaller) { |
| 57 | + this.comparator = comparator; |
| 58 | + this.keyMarshaller = keyMarshaller; |
| 59 | + } |
| 60 | + |
| 61 | + /** |
| 62 | + * Creates a new instance of AvlTreeMarshaller with the default key Marshaller which |
| 63 | + * uses Java Serialization. |
| 64 | + * @param comparator Comparator to be used for key comparision |
| 65 | + */ |
| 66 | + public ArrayMarshaller(Comparator<E> comparator) { |
| 67 | + this.comparator = comparator; |
| 68 | + this.keyMarshaller = DefaultMarshaller.INSTANCE; |
| 69 | + } |
| 70 | + |
| 71 | + /** |
| 72 | + * Marshals the given tree to bytes |
| 73 | + * @param tree the tree to be marshalled |
| 74 | + */ |
| 75 | + public byte[] serialize(ArrayTree<E> tree) { |
| 76 | + if ((tree == null) || (tree.size() == 0)) { |
| 77 | + return EMPTY_TREE; |
| 78 | + } |
| 79 | + |
| 80 | + ByteArrayOutputStream byteStream = new ByteArrayOutputStream(); |
| 81 | + DataOutputStream out = new DataOutputStream(byteStream); |
| 82 | + byte[] data = null; |
| 83 | + |
| 84 | + try { |
| 85 | + out.writeByte(0); // represents the start of an Array byte stream |
| 86 | + out.writeInt(tree.size()); |
| 87 | + |
| 88 | + for (int position = 0; position < tree.size(); position++) { |
| 89 | + E value = tree.get(position); |
| 90 | + byte[] bytes = this.keyMarshaller.serialize(value); |
| 91 | + |
| 92 | + // Write the key length |
| 93 | + out.writeInt(bytes.length); |
| 94 | + |
| 95 | + // Write the key if its length is not null |
| 96 | + if (bytes.length != 0) { |
| 97 | + out.write(bytes); |
| 98 | + } |
| 99 | + } |
| 100 | + |
| 101 | + out.flush(); |
| 102 | + data = byteStream.toByteArray(); |
| 103 | + |
| 104 | + // Try to deserialize, just to see |
| 105 | + try { |
| 106 | + deserialize(data); |
| 107 | + } |
| 108 | + catch (NullPointerException npe) { |
| 109 | + System.out.println("Bad serialization, tree : [" + StringTools.dumpBytes(data) + "]"); |
| 110 | + throw npe; |
| 111 | + } |
| 112 | + |
| 113 | + out.close(); |
| 114 | + } |
| 115 | + catch (IOException ex) { |
| 116 | + ex.printStackTrace(); |
| 117 | + } |
| 118 | + |
| 119 | + return data; |
| 120 | + } |
| 121 | + |
| 122 | + /** |
| 123 | + * Creates an Array from given bytes of data. |
| 124 | + * @param data byte array to be converted into an array |
| 125 | + */ |
| 126 | + public ArrayTree<E> deserialize(byte[] data) throws IOException { |
| 127 | + try { |
| 128 | + if ((data == null) || (data.length == 0)) { |
| 129 | + throw new IOException("Null or empty data array is invalid."); |
| 130 | + } |
| 131 | + |
| 132 | + if ((data.length == 1) && (data[0] == 0)) { |
| 133 | + E[] array = (E[]) new Object[] {}; |
| 134 | + ArrayTree<E> tree = new ArrayTree<E>(this.comparator, array); |
| 135 | + return tree; |
| 136 | + } |
| 137 | + |
| 138 | + ByteArrayInputStream bin = new ByteArrayInputStream(data); |
| 139 | + DataInputStream din = new DataInputStream(bin); |
| 140 | + |
| 141 | + byte startByte = din.readByte(); |
| 142 | + |
| 143 | + if (startByte != 0) { |
| 144 | + throw new IOException("wrong array serialized data format"); |
| 145 | + } |
| 146 | + |
| 147 | + int size = din.readInt(); |
| 148 | + E[] nodes = (E[]) new Object[size]; |
| 149 | + |
| 150 | + for (int i = 0; i < size; i++) { |
| 151 | + // Read the object's size |
| 152 | + int dataSize = din.readInt(); |
| 153 | + |
| 154 | + if (dataSize != 0) { |
| 155 | + byte[] bytes = new byte[dataSize]; |
| 156 | + |
| 157 | + din.read(bytes); |
| 158 | + E key = this.keyMarshaller.deserialize(bytes); |
| 159 | + nodes[i] = key; |
| 160 | + } |
| 161 | + } |
| 162 | + |
| 163 | + ArrayTree<E> arrayTree = new ArrayTree<E>(this.comparator, nodes); |
| 164 | + |
| 165 | + return arrayTree; |
| 166 | + } |
| 167 | + catch (NullPointerException npe) { |
| 168 | + System.out.println("Bad tree : [" + StringTools.dumpBytes(data) + "]"); |
| 169 | + throw npe; |
| 170 | + } |
| 171 | + } |
| 172 | + |
| 173 | +} |
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