com.pungwe.db.io.DBObjectReader.java Source code

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Here is the source code for com.pungwe.db.io.DBObjectReader.java

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/*
 * 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 com.pungwe.db.io;

import com.pungwe.db.constants.TypeReference;
import com.pungwe.db.types.BasicDBDocument;
import com.pungwe.db.types.DBDocument;
import org.joda.time.DateTime;
import org.joda.time.format.DateTimeFormatter;
import org.joda.time.format.ISODateTimeFormat;

import java.io.*;
import java.util.*;

/**
 * Created by ian on 01/08/2014.
 */
public class DBObjectReader {

    public static DBDocument read(byte[] buf) throws IOException {
        return read(new DataInputStream(new ByteArrayInputStream(buf)));
    }

    public static DBDocument read(DataInput input) throws IOException {
        ExtendedBasicDBDocument object = new ExtendedBasicDBDocument();
        // We don't really care about object length as we just iterate keys
        int keysRead = 0;
        int keys = input.readInt(); // First Integer is the key size of the document

        for (int i = 0; i < keys; i++) {
            // Ensure we are reading a document the first byte of each key should be "K". The document should comprise of keys
            if (input.readByte() != TypeReference.ENTRY.getType()) {
                throw new IllegalArgumentException("Provided data input is not a document");
            }
            // The next entry on a key should be the key timestamp
            long timestamp = input.readLong();
            // Get the key name
            String key = input.readUTF();
            // Read the key value
            Object value = readObject(input);

            // Create the object entry
            BasicDBDocument.BasicNode node = new BasicDBDocument.BasicNode(key, timestamp, value);
            object.addEntry(node);
        }

        return object;
    }

    private static DateTime readTimestamp(DataInput input) throws IOException {
        String dateString = input.readUTF();
        DateTimeFormatter fmt = ISODateTimeFormat.dateTime();
        return fmt.parseDateTime(dateString);
    }

    private static Object readObject(DataInput input) throws IOException {
        byte t = input.readByte();
        TypeReference type = TypeReference.fromType(t);
        switch (type) {
        case NULL:
            return null;
        case BOOLEAN:
            return input.readBoolean();
        case NUMBER:
            return input.readLong();
        case DECIMAL:
            return input.readDouble();
        case BINARY: {
            // Check for length
            int length = input.readInt();
            byte[] byteArray = new byte[length];
            input.readFully(byteArray);
            return byteArray;
        }
        case OBJECT: {
            return read(input);
        }
        case TIMESTAMP: {
            return readTimestamp(input);
        }
        case STRING: {
            return input.readUTF();
        }
        case ARRAY: {
            int size = input.readInt();
            List array = new ArrayList(size);
            for (int i = 0; i < size; i++) {
                Object value = readObject(input);
                array.add(value);
            }
            return array;
        }
        }
        return null;
    }

    private static class ExtendedBasicDBDocument extends BasicDBDocument {

        public void addEntry(BasicDBDocument.BasicNode n) {
            this.entries.add(n);
        }
    }
}