78 lines
3.6 KiB
HTML
78 lines
3.6 KiB
HTML
<HTML>
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<BODY>
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This documents the client API for using FoundationDB from Java.<br>
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<br>
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<h1>Installation</h1>
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FoundationDB's Java bindings rely on native libraries that are installed as part of the
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FoundationDB client binaries installation (see
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<a href="/foundationdb/api-general.html#installing-client-binaries" target="_blank">
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Installing FoundationDB client binaries</a>). The JAR can be downloaded from
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<a href="https://www.foundationdb.org/download/">our website</a>
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and then added to your classpath.<br>
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<br>
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<h1>Getting started</h1>
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To start using FoundationDB from Java, create an instance of the
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{@link com.apple.foundationdb.FDB FoundationDB API interface} with the version of the
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API that you want to use (this release of the FoundationDB Java API supports versions between {@code 510} and {@code 630}).
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With this API object you can then open {@link com.apple.foundationdb.Cluster Cluster}s and
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{@link com.apple.foundationdb.Database Database}s and start using
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{@link com.apple.foundationdb.Transaction Transaction}s.
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Here we give an example. The example relies on a cluster file at the
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<a href="/foundationdb/administration.html#default-cluster-file">default location</a>
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for your platform and a running server.<br>
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<br>
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<pre>
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{@code
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import com.apple.foundationdb.Database;
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import com.apple.foundationdb.FDB;
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import com.apple.foundationdb.tuple.Tuple;
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public class Example {
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public static void main(String[] args) {
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FDB fdb = FDB.selectAPIVersion(630);
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try(Database db = fdb.open()) {
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// Run an operation on the database
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db.run(tr -> {
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tr.set(Tuple.from("hello").pack(), Tuple.from("world").pack());
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return null;
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});
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// Get the value of 'hello' from the database
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String hello = db.run(tr -> {
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byte[] result = tr.get(Tuple.from("hello").pack()).join();
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return Tuple.fromBytes(result).getString(0);
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});
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System.out.println("Hello " + hello);
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}
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}
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}
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}
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</pre>
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<h1>FoundationDB {@link com.apple.foundationdb.tuple Tuple API}</h1>
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The {@link com.apple.foundationdb.tuple Tuple API} is provided with the core Java API for FoundationDB.
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This layer is provided in some form in all official language bindings. It enables
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cross-language support for storing and retrieving typed data from the
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binary data that FoundationDB supports. And, just as importantly, data packed into
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{@code Tuple}s and used as keys sort in predictable and useful ways. See the
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{@link com.apple.foundationdb.tuple Tuple class documentation} for information about use in Java
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and <a href="/foundationdb/data-modeling.html#data-modeling-tuples">general Tuple documentation</a>
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for information about how Tuples sort and can be used to efficiently model data.
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<br>
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<h1>FoundationDB {@link com.apple.foundationdb.directory Directory API}</h1>
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The {@link com.apple.foundationdb.directory Directory API} is provided with the core
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Java API for FoundationDB. This layer is provided in some form in all official
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language bindings. The FoundationDB API provides directories as a tool for
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managing related {@link com.apple.foundationdb.subspace.Subspace Subspace}s. Directories are a
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recommended approach for administering applications. Each application should
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create or open at least one directory to manage its subspaces. Directories are
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identified by hierarchical paths analogous to the paths in a Unix-like file system.
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A path is represented as a List of strings. Each directory has an associated
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subspace used to store its content. The layer maps each path to a short prefix used
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for the corresponding subspace. In effect, directories provide a level of indirection
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for access to subspaces.
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</BODY>
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</HTML>
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