Add response class and link header support

Responses that contain paginated results contain a
Link header to request uris relative to the current
response.

Change-Id: I372bb065b6fa2937c0039491851a03547f7a0b90
Signed-off-by: Kevin Sawicki <kevin@github.com>
Signed-off-by: Chris Aniszczyk <caniszczyk@gmail.com>

3 files changed, 234 insertions, 0 deletions

diff --git a/org.eclipse.mylyn.github.core/src/org/eclipse/mylyn/github/internal/GitHubResponse.java b/org.eclipse.mylyn.github.core/src/org/eclipse/mylyn/github/internal/GitHubResponse.java
new file mode 100644
index 00000000..e10d39af
--- /dev/null
+++ b/org.eclipse.mylyn.github.core/src/org/eclipse/mylyn/github/internal/GitHubResponse.java
@@ -0,0 +1,80 @@
+/*******************************************************************************
+ *  Copyright (c) 2011 GitHub Inc.
+ *  All rights reserved. This program and the accompanying materials
+ *  are made available under the terms of the Eclipse Public License v1.0
+ *  which accompanies this distribution, and is available at
+ *  http://www.eclipse.org/legal/epl-v10.html
+ *
+ *  Contributors:
+ *    Kevin Sawicki (GitHub Inc.) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.mylyn.github.internal;
+
+import org.apache.commons.httpclient.HttpMethod;
+
+/**
+ * GitHub API response class.
+ */
+public class GitHubResponse {
+
+	private PageLinks links;
+
+	private Object body;
+
+	/**
+	 * Create response
+	 * 
+	 * @param method
+	 * @param body
+	 */
+	public GitHubResponse(HttpMethod method, Object body) {
+		links = new PageLinks(method);
+		this.body = body;
+	}
+
+	/**
+	 * Get link uri to first page
+	 * 
+	 * @return possibly null uri
+	 */
+	public String getFirst() {
+		return this.links.getFirst();
+	}
+
+	/**
+	 * Get link uri to previous page
+	 * 
+	 * @return possibly null uri
+	 */
+	public String getPrevious() {
+		return this.links.getPrev();
+	}
+
+	/**
+	 * Get link uri to next page
+	 * 
+	 * @return possibly null uri
+	 */
+	public String getNext() {
+		return this.links.getNext();
+	}
+
+	/**
+	 * Get link uri to last page
+	 * 
+	 * @return possibly null uri
+	 */
+	public String getLast() {
+		return this.links.getLast();
+	}
+
+	/**
+	 * Parsed response body
+	 * 
+	 * @return body
+	 */
+	public Object getBody() {
+		return this.body;
+	}
+
+}
diff --git a/org.eclipse.mylyn.github.core/src/org/eclipse/mylyn/github/internal/PageLinks.java b/org.eclipse.mylyn.github.core/src/org/eclipse/mylyn/github/internal/PageLinks.java
new file mode 100644
index 00000000..0d5a030a
--- /dev/null
+++ b/org.eclipse.mylyn.github.core/src/org/eclipse/mylyn/github/internal/PageLinks.java
@@ -0,0 +1,112 @@
+/*******************************************************************************
+ *  Copyright (c) 2011 GitHub Inc.
+ *  All rights reserved. This program and the accompanying materials
+ *  are made available under the terms of the Eclipse Public License v1.0
+ *  which accompanies this distribution, and is available at
+ *  http://www.eclipse.org/legal/epl-v10.html
+ *
+ *  Contributors:
+ *    Kevin Sawicki (GitHub Inc.) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.mylyn.github.internal;
+
+import org.apache.commons.httpclient.Header;
+import org.apache.commons.httpclient.HttpMethod;
+
+/**
+ * Page link class to be used to determine the links to other pages of request
+ * responses encoded in the current response. These will be present if the
+ * result set size exceeds the per page limit.
+ */
+public class PageLinks {
+
+	private static final String DELIM_LINKS = ","; //$NON-NLS-1$
+
+	private static final String DELIM_LINK_PARAM = ";"; //$NON-NLS-1;$
+
+	private String first;
+	private String last;
+	private String next;
+	private String prev;
+
+	/**
+	 * Parse links from executed method
+	 * 
+	 * @param method
+	 */
+	public PageLinks(HttpMethod method) {
+		Header[] linkHeaders = method
+				.getResponseHeaders(IGitHubConstants.HEADER_LINK);
+		if (linkHeaders.length > 0) {
+			String[] links = linkHeaders[0].getValue().split(DELIM_LINKS);
+			for (String link : links) {
+				String[] segments = link.split(DELIM_LINK_PARAM);
+				if (segments.length < 2)
+					continue;
+
+				String linkPart = segments[0].trim();
+				if (!linkPart.startsWith("<") || !linkPart.endsWith(">")) //$NON-NLS-1$ //$NON-NLS-2$
+					continue;
+				linkPart = linkPart.substring(1, linkPart.length() - 1);
+
+				for (int i = 1; i < segments.length; i++) {
+					String[] rel = segments[i].trim().split("="); //$NON-NLS-1$
+					if (rel.length < 2
+							|| !IGitHubConstants.META_REL.equals(rel[0]))
+						continue;
+
+					String relValue = rel[1];
+					if (relValue.startsWith("\"") && relValue.endsWith("\"")) //$NON-NLS-1$ //$NON-NLS-2$
+						relValue = relValue.substring(1, relValue.length() - 1);
+
+					if (IGitHubConstants.META_FIRST.equals(relValue))
+						first = linkPart;
+					else if (IGitHubConstants.META_LAST.equals(relValue))
+						last = linkPart;
+					else if (IGitHubConstants.META_NEXT.equals(relValue))
+						next = linkPart;
+					else if (IGitHubConstants.META_PREV.equals(relValue))
+						prev = linkPart;
+				}
+			}
+		} else {
+			Header[] nextHeaders = method
+					.getResponseHeaders(IGitHubConstants.HEADER_NEXT);
+			if (nextHeaders.length > 0)
+				next = nextHeaders[0].getValue();
+
+			Header[] lastHeaders = method
+					.getResponseHeaders(IGitHubConstants.HEADER_LAST);
+			if (lastHeaders.length > 0)
+				last = lastHeaders[0].getValue();
+		}
+	}
+
+	/**
+	 * @return first
+	 */
+	public String getFirst() {
+		return this.first;
+	}
+
+	/**
+	 * @return last
+	 */
+	public String getLast() {
+		return this.last;
+	}
+
+	/**
+	 * @return next
+	 */
+	public String getNext() {
+		return this.next;
+	}
+
+	/**
+	 * @return prev
+	 */
+	public String getPrev() {
+		return this.prev;
+	}
+}
diff --git a/org.eclipse.mylyn.github.core/src/org/eclipse/mylyn/github/internal/PagedRequest.java b/org.eclipse.mylyn.github.core/src/org/eclipse/mylyn/github/internal/PagedRequest.java
new file mode 100644
index 00000000..b61f0e07
--- /dev/null
+++ b/org.eclipse.mylyn.github.core/src/org/eclipse/mylyn/github/internal/PagedRequest.java
@@ -0,0 +1,42 @@
+/*******************************************************************************
+ *  Copyright (c) 2011 GitHub Inc.
+ *  All rights reserved. This program and the accompanying materials
+ *  are made available under the terms of the Eclipse Public License v1.0
+ *  which accompanies this distribution, and is available at
+ *  http://www.eclipse.org/legal/epl-v10.html
+ *
+ *  Contributors:
+ *    Kevin Sawicki (GitHub Inc.) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.mylyn.github.internal;
+
+import org.eclipse.core.runtime.Assert;
+
+/**
+ * Pages request class that contains a collector for accept resources page by
+ * page.
+ * 
+ * @param <V>
+ */
+public class PagedRequest<V> extends GitHubRequest {
+
+	private IResourceCollector<V> collector;
+
+	/**
+	 * Create paged request with non-null collector
+	 * 
+	 * @param collector
+	 */
+	public PagedRequest(IResourceCollector<V> collector) {
+		Assert.isNotNull(collector, "Collecto cannot be null"); //$NON-NLS-1$
+		this.collector = collector;
+	}
+
+	/**
+	 * @return collector
+	 */
+	public IResourceCollector<V> getCollector() {
+		return this.collector;
+	}
+
+}