| /** |
| * 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.trevni; |
| |
| import java.io.IOException; |
| import java.nio.charset.Charset; |
| import java.util.Map; |
| import java.util.LinkedHashMap; |
| |
| /** Base class for metadata. */ |
| public class MetaData<T extends MetaData> extends LinkedHashMap<String,byte[]> { |
| |
| static final String RESERVED_KEY_PREFIX = "trevni."; |
| |
| static final String CODEC_KEY = RESERVED_KEY_PREFIX + "codec"; |
| static final String CHECKSUM_KEY = RESERVED_KEY_PREFIX + "checksum"; |
| |
| public static final Charset UTF8 = Charset.forName("UTF-8"); |
| |
| private MetaData<?> defaults; |
| |
| void setDefaults(MetaData defaults) { this.defaults = defaults; } |
| |
| /** Return the compression codec name. */ |
| public String getCodec() { return getString(CODEC_KEY); } |
| |
| /** Set the compression codec name. */ |
| public T setCodec(String codec) { |
| setReserved(CODEC_KEY, codec); |
| return (T)this; |
| } |
| |
| /** Return the checksum algorithm name. */ |
| public String getChecksum() { return getString(CHECKSUM_KEY); } |
| |
| /** Set the checksum algorithm name. */ |
| public T setChecksum(String checksum) { |
| setReserved(CHECKSUM_KEY, checksum); |
| return (T)this; |
| } |
| |
| /** Return the value of a metadata property as a String. */ |
| public String getString(String key) { |
| byte[] value = get(key); |
| if (value == null && defaults != null) |
| value = defaults.get(key); |
| if (value == null) |
| return null; |
| return new String(value, UTF8); |
| } |
| |
| /** Return the value of a metadata property as a long. */ |
| public long getLong(String key) { |
| return Long.parseLong(getString(key)); |
| } |
| |
| /** Return true iff a key has any value, false if it is not present. */ |
| public boolean getBoolean(String key) { |
| return get(key) != null; |
| } |
| |
| /** Set a metadata property to a binary value. */ |
| public T set(String key, byte[] value) { |
| if (isReserved(key)) { |
| throw new TrevniRuntimeException("Cannot set reserved key: " + key); |
| } |
| put(key, value); |
| return (T)this; |
| } |
| |
| /** Test if a metadata key is reserved. */ |
| public static boolean isReserved(String key) { |
| return key.startsWith(RESERVED_KEY_PREFIX); |
| } |
| |
| /** Set a metadata property to a String value. */ |
| public T set(String key, String value) { |
| return set(key, value.getBytes(UTF8)); |
| } |
| |
| T setReserved(String key, String value) { |
| put(key, value.getBytes(UTF8)); |
| return (T)this; |
| } |
| |
| T setReservedBoolean(String key, boolean value) { |
| if (value) |
| setReserved(key, ""); |
| else |
| remove(key); |
| return (T)this; |
| } |
| |
| /** Set a metadata property to a long value. */ |
| public T set(String key, long value) { |
| return set(key, Long.toString(value)); |
| } |
| |
| void write(OutputBuffer out) throws IOException { |
| out.writeInt(size()); |
| for (Map.Entry<String,byte[]> e : entrySet()) { |
| out.writeString(e.getKey()); |
| out.writeBytes(e.getValue()); |
| } |
| } |
| |
| static void read(InputBuffer in, MetaData<?> metaData) throws IOException { |
| int size = in.readInt(); |
| for (int i = 0; i < size; i++) |
| metaData.put(in.readString(), in.readBytes()); |
| } |
| |
| @Override public String toString() { |
| StringBuffer buffer = new StringBuffer(); |
| buffer.append("{ "); |
| for (Map.Entry<String,byte[]> e : entrySet()) { |
| buffer.append(e.getKey()); |
| buffer.append("="); |
| try { |
| buffer.append(new String(e.getValue(), "ISO-8859-1")); |
| } catch (java.io.UnsupportedEncodingException error) { |
| throw new TrevniRuntimeException(error); |
| } |
| buffer.append(" "); |
| } |
| buffer.append("}"); |
| return buffer.toString(); |
| } |
| |
| } |