Merge the matrix-java-sdk due to it no longer maintained. Remove thirdparty repositories.

src/main/java/io/kamax/matrix/crypto/KeyFileStore.java

@@ -0,0 +1,80 @@
+/*
+ * matrix-java-sdk - Matrix Client SDK for Java
+ * Copyright (C) 2017 Kamax Sarl
+ *
+ * https://www.kamax.io/
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package io.kamax.matrix.crypto;
+
+import org.apache.commons.io.FileUtils;
+import org.apache.commons.lang3.StringUtils;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+
+public class KeyFileStore implements _KeyStore {
+
+    private final Charset charset = StandardCharsets.UTF_8;
+
+    private File file;
+
+    public KeyFileStore(String path) {
+        File file = new File(path);
+        if (!file.exists()) {
+            throw new IllegalArgumentException("Signing key file storage " + path + " does not exist");
+        }
+
+        if (file.isDirectory()) {
+            throw new IllegalArgumentException("Signing key file storage " + path + " is a directory");
+        }
+
+        if (!file.isFile()) {
+            throw new IllegalArgumentException("Signing key file storage " + path + " is not a regular file");
+        }
+
+        if (!file.canRead()) {
+            throw new IllegalArgumentException("Signing key file storage " + path + " is not readable");
+        }
+
+        this.file = file;
+    }
+
+    @Override
+    public Optional<String> load() {
+        try {
+            List<String> keys = FileUtils.readLines(file, charset);
+            return keys.stream().filter(StringUtils::isNotBlank).findFirst();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    @Override
+    public void store(String key) {
+        try {
+            FileUtils.writeLines(file, charset.name(), Collections.singletonList(key), false);
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+}