org.apache.jackrabbit.oak.plugins.blob.datastore.InMemoryDataRecord Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.jackrabbit.oak.plugins.blob.datastore;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.util.Arrays;
import org.apache.jackrabbit.core.data.DataIdentifier;
import org.apache.jackrabbit.core.data.DataRecord;
import org.apache.jackrabbit.core.data.DataStoreException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Represents binary data which is backed by a byte[] (in memory).
*/
public class InMemoryDataRecord implements DataRecord {
/**
* Logger instance for this class
*/
private static Logger log = LoggerFactory.getLogger(InMemoryDataRecord.class);
/**
* the prefix of the string representation of this value
*/
private static final String PREFIX = "0x";
/**
* the data
*/
private final byte[] data;
private DataIdentifier identifier;
/**
* empty array
*/
private static final byte[] EMPTY_BYTE_ARRAY = new byte[0];
/**
* empty instance
*/
private static final InMemoryDataRecord EMPTY = new InMemoryDataRecord(EMPTY_BYTE_ARRAY);
/**
* Creates a new instance from a
* byte[]
array.
*
* @param data the byte array
*/
private InMemoryDataRecord(byte[] data) {
this.data = data;
}
/**
* Creates a new instance from a
* byte[]
array.
*
* @param data the byte array
*/
static InMemoryDataRecord getInstance(byte[] data) {
if (data.length == 0) {
return EMPTY;
} else {
return new InMemoryDataRecord(data);
}
}
/**
* Checks if String can be converted to an instance of this class.
* @param id DataRecord identifier
* @return true if it can be converted
*/
public static boolean isInstance(String id) {
return id.startsWith(PREFIX);
}
/**
* Convert a String to an instance of this class.
* @param id DataRecord identifier
* @return the instance
*/
public static InMemoryDataRecord getInstance(String id) throws IllegalArgumentException {
assert id.startsWith(PREFIX);
id = id.substring(PREFIX.length());
int len = id.length();
if (len % 2 != 0) {
String msg = "unable to deserialize byte array " + id + " , length=" + id.length();
log.debug(msg);
throw new IllegalArgumentException(msg);
}
len /= 2;
byte[] data = new byte[len];
try {
for (int i = 0; i < len; i++) {
data[i] = (byte) ((Character.digit(id.charAt(2 * i), 16) << 4) | (Character.digit(id.charAt(2 * i + 1), 16)));
}
} catch (NumberFormatException e) {
String msg = "unable to deserialize byte array " + id;
log.debug(msg);
throw new IllegalArgumentException(msg);
}
return InMemoryDataRecord.getInstance(data);
}
@Override
public DataIdentifier getIdentifier() {
if (identifier == null) {
identifier = new DataIdentifier(toString());
}
return identifier;
}
@Override
public String getReference() {
return null;
}
@Override
public long getLength() throws DataStoreException {
return data.length;
}
public InputStream getStream() {
return new ByteArrayInputStream(data);
}
@Override
public long getLastModified() {
return 0;
}
public String toString() {
StringBuilder buff = new StringBuilder(PREFIX.length() + 2 * data.length);
buff.append(PREFIX);
for (byte aData : data) {
int c = aData & 0xff;
buff.append(Integer.toHexString(c >> 4));
buff.append(Integer.toHexString(c & 0xf));
}
return buff.toString();
}
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj instanceof InMemoryDataRecord) {
InMemoryDataRecord other = (InMemoryDataRecord) obj;
return Arrays.equals(data, other.data);
}
return false;
}
/**
* Returns zero to satisfy the Object equals/hashCode contract.
* This class is mutable and not meant to be used as a hash key.
*
* @return always zero
* @see Object#hashCode()
*/
public int hashCode() {
return 0;
}
}