Java tutorial
package org.apache.cassandra.db.marshal; /* * * 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. * */ import java.nio.ByteBuffer; import java.text.ParseException; import java.util.UUID; import java.util.regex.Pattern; import org.apache.cassandra.utils.ByteBufferUtil; import org.apache.cassandra.utils.FBUtilities; import org.apache.cassandra.utils.UUIDGen; import org.apache.commons.lang.time.DateUtils; public class TimeUUIDType extends AbstractUUIDType { public static final TimeUUIDType instance = new TimeUUIDType(); static final Pattern regexPattern = Pattern .compile("[A-Fa-f0-9]{8}\\-[A-Fa-f0-9]{4}\\-[A-Fa-f0-9]{4}\\-[A-Fa-f0-9]{4}\\-[A-Fa-f0-9]{12}"); static final String[] iso8601Patterns = new String[] { "yyyy-MM-dd HH:mm", "yyyy-MM-dd HH:mm:ss", "yyyy-MM-dd HH:mmZ", "yyyy-MM-dd HH:mm:ssZ", "yyyy-MM-dd'T'HH:mm", "yyyy-MM-dd'T'HH:mmZ", "yyyy-MM-dd'T'HH:mm:ss", "yyyy-MM-dd'T'HH:mm:ssZ", "yyyy-MM-dd", "yyyy-MM-ddZ" }; TimeUUIDType() { } // singleton public UUID compose(ByteBuffer bytes) { return UUIDGen.getUUID(bytes); } public ByteBuffer decompose(UUID value) { return ByteBuffer.wrap(UUIDGen.decompose(value)); } public int compare(ByteBuffer o1, ByteBuffer o2) { if (o1.remaining() == 0) { return o2.remaining() == 0 ? 0 : -1; } if (o2.remaining() == 0) { return 1; } int res = compareTimestampBytes(o1, o2); if (res != 0) return res; return o1.compareTo(o2); } private static int compareTimestampBytes(ByteBuffer o1, ByteBuffer o2) { int o1Pos = o1.position(); int o2Pos = o2.position(); int d = (o1.get(o1Pos + 6) & 0xF) - (o2.get(o2Pos + 6) & 0xF); if (d != 0) return d; d = (o1.get(o1Pos + 7) & 0xFF) - (o2.get(o2Pos + 7) & 0xFF); if (d != 0) return d; d = (o1.get(o1Pos + 4) & 0xFF) - (o2.get(o2Pos + 4) & 0xFF); if (d != 0) return d; d = (o1.get(o1Pos + 5) & 0xFF) - (o2.get(o2Pos + 5) & 0xFF); if (d != 0) return d; d = (o1.get(o1Pos) & 0xFF) - (o2.get(o2Pos) & 0xFF); if (d != 0) return d; d = (o1.get(o1Pos + 1) & 0xFF) - (o2.get(o2Pos + 1) & 0xFF); if (d != 0) return d; d = (o1.get(o1Pos + 2) & 0xFF) - (o2.get(o2Pos + 2) & 0xFF); if (d != 0) return d; return (o1.get(o1Pos + 3) & 0xFF) - (o2.get(o2Pos + 3) & 0xFF); } public String getString(ByteBuffer bytes) { if (bytes.remaining() == 0) { return ""; } if (bytes.remaining() != 16) { throw new MarshalException("UUIDs must be exactly 16 bytes"); } UUID uuid = UUIDGen.getUUID(bytes); if (uuid.version() != 1) { throw new MarshalException("TimeUUID only makes sense with version 1 UUIDs"); } return uuid.toString(); } public String toString(UUID uuid) { return uuid.toString(); } public ByteBuffer fromString(String source) throws MarshalException { // Return an empty ByteBuffer for an empty string. if (source.isEmpty()) return ByteBufferUtil.EMPTY_BYTE_BUFFER; ByteBuffer idBytes = null; // ffffffff-ffff-ffff-ffff-ffffffffff if (regexPattern.matcher(source).matches()) { UUID uuid = null; try { uuid = UUID.fromString(source); idBytes = decompose(uuid); } catch (IllegalArgumentException e) { throw new MarshalException(String.format("unable to make UUID from '%s'", source), e); } if (uuid.version() != 1) throw new MarshalException("TimeUUID supports only version 1 UUIDs"); } else if (source.toLowerCase().equals("now")) { idBytes = ByteBuffer .wrap(UUIDGen.decompose(UUIDGen.makeType1UUIDFromHost(FBUtilities.getLocalAddress()))); } // Milliseconds since epoch? else if (source.matches("^\\d+$")) { try { idBytes = ByteBuffer.wrap(UUIDGen.getTimeUUIDBytes(Long.parseLong(source))); } catch (NumberFormatException e) { throw new MarshalException(String.format("unable to make version 1 UUID from '%s'", source), e); } } // Last chance, attempt to parse as date-time string else { try { long timestamp = DateUtils.parseDate(source, iso8601Patterns).getTime(); idBytes = ByteBuffer.wrap(UUIDGen.getTimeUUIDBytes(timestamp)); } catch (ParseException e1) { throw new MarshalException(String.format("unable to coerce '%s' to version 1 UUID", source), e1); } } return idBytes; } public void validate(ByteBuffer bytes) throws MarshalException { if (bytes.remaining() != 16 && bytes.remaining() != 0) throw new MarshalException(String.format("TimeUUID should be 16 or 0 bytes (%d)", bytes.remaining())); ByteBuffer slice = bytes.slice(); // version is bits 4-7 of byte 6. if (bytes.remaining() > 0) { slice.position(6); if ((slice.get() & 0xf0) != 0x10) throw new MarshalException("Invalid version for TimeUUID type."); } } public Class<UUID> getType() { return UUID.class; } }