fyrz
10 years ago
parent
fa9cfc65f3
commit
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// Copyright (c) 2014, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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import org.rocksdb.*; |
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import java.util.ArrayList; |
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import java.util.List; |
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public class RocksDBColumnFamilySample { |
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static { |
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RocksDB.loadLibrary(); |
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} |
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public static void main(String[] args) throws RocksDBException { |
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if (args.length < 1) { |
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System.out.println( |
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"usage: RocksDBColumnFamilySample db_path"); |
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return; |
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} |
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String db_path = args[0]; |
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System.out.println("RocksDBColumnFamilySample"); |
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RocksDB db = null; |
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DBOptions dbOptions = null; |
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List<RocksIterator> iterators = new ArrayList<>(); |
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RocksIterator iterator = null; |
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ColumnFamilyHandle cfHandle = null; |
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WriteBatch wb = null; |
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try { |
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// Setup DBOptions
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dbOptions = new DBOptions(). |
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setCreateIfMissing(true). |
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setCreateMissingColumnFamilies(true); |
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// Setup ColumnFamily descriptors
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List<ColumnFamilyDescriptor> cfNames = |
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new ArrayList<>(); |
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// Default column family
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cfNames.add(new ColumnFamilyDescriptor("default")); |
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// New column families
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cfNames.add(new ColumnFamilyDescriptor("cf_green", |
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new ColumnFamilyOptions().setComparator( |
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BuiltinComparator.BYTEWISE_COMPARATOR))); |
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cfNames.add(new ColumnFamilyDescriptor("cf_blue", |
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new ColumnFamilyOptions().setComparator( |
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BuiltinComparator.REVERSE_BYTEWISE_COMPARATOR))); |
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cfNames.add(new ColumnFamilyDescriptor("cf_red", |
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new ColumnFamilyOptions(). |
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setMergeOperator(new StringAppendOperator()))); |
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List<ColumnFamilyHandle> cfHandles = |
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new ArrayList<>(); |
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db = RocksDB.open(dbOptions, |
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db_path, cfNames, cfHandles); |
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// List column families in database
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System.out.println("List existent column families:"); |
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List<byte[]> cfListing = RocksDB.listColumnFamilies( |
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new Options(), db_path); |
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for (byte[] cf : cfListing) { |
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System.out.format(" - %s\n", new String(cf)); |
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} |
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// Bootstrapping values
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System.out.println("Writing values to database."); |
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for (int i=0; i < cfNames.size(); i++) { |
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for (int j=0; j < 10; j++) { |
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db.put(cfHandles.get(i), |
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String.valueOf(j).getBytes(), |
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String.valueOf(j).getBytes()); |
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} |
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} |
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// Retrieve values using get
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System.out.println("Retrieve values with get."); |
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for (int i=0; i < cfNames.size(); i++) { |
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for (int j=0; j < 10; j++) { |
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System.out.format(" %s", new String( |
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db.get(cfHandles.get(i), |
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String.valueOf(j).getBytes()))); |
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} |
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System.out.println(""); |
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} |
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// Add a new column family to existing database
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System.out.println("Add new column family"); |
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cfHandle = db.createColumnFamily(new ColumnFamilyDescriptor( |
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"cf_temp", new ColumnFamilyOptions(). |
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setMergeOperator(new StringAppendOperator()))); |
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System.out.println("Write key/value into new column family."); |
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db.put(cfHandle, "key".getBytes(), "value".getBytes()); |
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System.out.format("Lookup 'key' retrieved value: %s\n", new String( |
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db.get(cfHandle, "key".getBytes()))); |
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// Delete key
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System.out.println("Delete key/value in new column family."); |
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db.remove(cfHandle, "key".getBytes()); |
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// WriteBatch with column family
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wb = new WriteBatch(); |
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wb.put(cfHandle, "key".getBytes(), "value".getBytes()); |
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wb.put(cfHandle, "key2".getBytes(), "value2".getBytes()); |
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wb.remove(cfHandle, "key2".getBytes()); |
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wb.merge(cfHandle, "key".getBytes(), "morevalues".getBytes()); |
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db.write(new WriteOptions(), wb); |
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// Retrieve a single iterator with a cf handle
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System.out.println("Retrieve values using a iterator on" + |
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" a column family."); |
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iterator = db.newIterator(cfHandle); |
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iterator.seekToFirst(); |
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while(iterator.isValid()) { |
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System.out.format(" %s", new String( |
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iterator.value())); |
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iterator.next(); |
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} |
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System.out.println(""); |
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// Delete column family
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System.out.println("Delete column family."); |
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db.dropColumnFamily(cfHandle); |
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// Retrieve values from cf using iterator
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System.out.println("Retrieve values with iterators"); |
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iterators = db.newIterators(cfHandles); |
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assert(iterators.size() == 4); |
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for (RocksIterator iter : iterators) { |
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iter.seekToFirst(); |
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while(iter.isValid()) { |
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System.out.format(" %s", new String( |
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iter.value())); |
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iter.next(); |
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} |
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System.out.println(""); |
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} |
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} finally { |
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if (db != null) { |
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db.close(); |
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} |
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if (dbOptions != null) { |
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dbOptions.dispose(); |
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} |
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if (iterator != null) { |
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iterator.dispose(); |
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} |
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for (RocksIterator iter : iterators) { |
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iter.dispose(); |
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} |
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if (wb != null) { |
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wb.dispose(); |
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} |
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} |
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} |
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} |
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