Add implementation of a Link class

Author: acoburn

src/main/java/org/trellisldp/camel/Link.java

@@ -0,0 +1,91 @@
+/*
+ * Licensed 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.trellisldp.camel;
+
+import static java.util.Collections.unmodifiableMap;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * @author acoburn
+ */
+public class Link {
+
+    private final String uri;
+
+    private final Map<String, String> params = new HashMap<>();
+
+    /**
+     * Create a Link object from an HTTP header
+     * @param value the value of the link header
+     */
+    public Link(final String value) {
+        final String[] parts = value.split(";");
+        if (parts.length >= 1) {
+            final String val = parts[0].trim();
+            this.uri = val.startsWith("<") && val.endsWith(">") ? val.substring(1, val.length() - 1) : null;
+            for (int i = 1; i < parts.length; i++) {
+                final String[] p = parts[1].trim().split("=");
+                if (p.length == 2) {
+                    if (!params.containsKey(p[0])) {
+                        params.put(p[0], p[1]);
+                    }
+                }
+            }
+        } else {
+            this.uri = null;
+        }
+    }
+
+    /**
+     * Get the URI portion of the link header
+     * @return the URI
+     */
+    public String getUri() {
+        return uri;
+    }
+
+    /**
+     * Get the type portion of the link header, if one exists
+     * @return the type or null if one doesn not exist
+     */
+    public String getType() {
+        return params.get("type");
+    }
+
+    /**
+     * Get the title portion of the link header, if one exists
+     * @return the title or null if one doesn not exist
+     */
+    public String getTitle() {
+        return params.get("title");
+    }
+
+    /**
+     * Get the rel portion of the link header, if one exists
+     * @return the rel or null if one doesn not exist
+     */
+    public String getRel() {
+        return params.get("rel");
+    }
+
+    /**
+     * Get all defined parameters from the link header, including type, rel and title if they exist.
+     * @return the header parameters
+     */
+    public Map<String, String> getParams() {
+        return unmodifiableMap(params);
+    }
+}