Add an ObjectId class for identifying stored objects

gcloud-java-storage/src/main/java/com/google/gcloud/storage/ObjectId.java

@@ -0,0 +1,133 @@
+/*
+ * Copyright 2015 Google Inc. All Rights Reserved.
+ *
+ * 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 com.google.gcloud.storage;
+
+import java.net.URI;
+import java.util.Objects;
+
+/**
+ * Identifier for a stored object.
+ */
+public class ObjectId {
+
+    private final String bucketName;
+    private final String objectName;
+    private final URI uri;
+
+    public ObjectId(String uri) {
+        this(URI.create(uri));
+    }
+
+    /**
+     * Constructs an ObjectId from a {@code gsutil} style URI.
+     *
+     * @param uri the object's URI
+     */
+    public ObjectId(URI uri) {
+        Objects.requireNonNull(uri, "uri must not be null");
+        this.uri = uri;
+        if (uri.isAbsolute()) {
+            if (!"gs".equals(uri.getScheme())) {
+                throw new IllegalArgumentException("uri must use gs: scheme");
+            }
+            if (uri.getPath() == null || uri.getPath().length() <= 1) {
+                throw new IllegalArgumentException("uri must have a path: " + uri);
+            }
+            bucketName = uri.getAuthority();
+            objectName = uri.getPath().substring(1);
+        } else {
+            this.bucketName = null;
+            this.objectName = uri.getPath();
+        }
+    }
+
+    /**
+     * Construct an absolute ObjectId from a bucket and object name.
+     *
+     * @param bucketName name of the bucket
+     * @param objectName name of the object; must be a path relative to the bucket i.e. must not start with '/'
+     */
+    public ObjectId(String bucketName, String objectName) {
+        Objects.requireNonNull(bucketName, "bucketName must not be null");
+        if (bucketName.isEmpty()) {
+            throw new IllegalArgumentException("bucketName must not be empty");
+        }
+        Objects.requireNonNull(objectName, "objectName must not be null");
+        if (objectName.isEmpty()) {
+            throw new IllegalArgumentException("objectName must not be empty");
+        }
+        if (objectName.charAt(0) == '/') {
+            throw new IllegalArgumentException("objectName must be a relative path");
+        }
+        this.bucketName = bucketName;
+        this.objectName = objectName;
+        this.uri = URI.create("gs://" + bucketName + "/" + objectName);
+    }
+
+    /**
+     * Returns the name of the bucket containing this object. May be null for object ids that solely define an
+     * object name independent of bucket.
+     *
+     * @return the name of the bucket containing this object; may be null
+     */
+    public String getBucketName() {
+        return bucketName;
+    }
+
+    /**
+     * Returns the name of the object within the bucket.
+     * @return the name of the object within the bucket
+     */
+    public String getObjectName() {
+        return objectName;
+    }
+
+    /**
+     * Returns the {@code gsutil} URI for this object.
+     *
+     * <p>If a bucketName is defined this will return an absolute URI of the form {@code gs://bucketName/objectName},
+     * otherwise the objectName will be converted to a relative URI.
+     *
+     * @return the uri for this object
+     */
+    public URI toURI() {
+        return uri;
+    }
+
+    /**
+     * Returns this objects URI as a String.
+     * @return this objects URI as a String
+     */
+    @Override
+    public String toString() {
+        return uri.toString();
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ObjectId other = (ObjectId) o;
+        return Objects.equals(bucketName, other.bucketName) &&
+                Objects.equals(objectName, other.objectName);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(bucketName, objectName);
+    }
+}

gcloud-java-storage/src/test/java/com/google/gcloud/storage/ObjectIdTest.java

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+/*
+ * Copyright 2015 Google Inc. All Rights Reserved.
+ *
+ * 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 com.google.gcloud.storage;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+import java.net.URI;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+public class ObjectIdTest {
+
+    @Rule
+    public ExpectedException thrown = ExpectedException.none();
+
+    @Test
+    public void createWithBucketAndObjectName() {
+        ObjectId id = new ObjectId("bucket", "path/to/object.txt");
+        assertEquals("bucket", id.getBucketName());
+        assertEquals("path/to/object.txt", id.getObjectName());
+        assertEquals("gs://bucket/path/to/object.txt", id.toString());
+        assertEquals(URI.create("gs://bucket/path/to/object.txt"), id.toURI());
+    }
+
+    @Test
+    public void createFromRelativeURI() {
+        ObjectId id = new ObjectId("path/to/object.txt");
+        assertNull(id.getBucketName());
+        assertEquals("path/to/object.txt", id.getObjectName());
+        assertEquals("path/to/object.txt", id.toString());
+        assertEquals(URI.create("path/to/object.txt"), id.toURI());
+    }
+
+    @Test
+    public void createFromAbsoluteURI() {
+        ObjectId id = new ObjectId("gs://bucket/path/to/object.txt");
+        assertEquals("bucket", id.getBucketName());
+        assertEquals("path/to/object.txt", id.getObjectName());
+        assertEquals("gs://bucket/path/to/object.txt", id.toString());
+        assertEquals(URI.create("gs://bucket/path/to/object.txt"), id.toURI());
+    }
+
+    @Test
+    public void nullBucketNameNotAllowed() {
+        thrown.expect(NullPointerException.class);
+        new ObjectId(null, "object");
+    }
+
+    @Test
+    public void emptyBucketNameNotAllowed() {
+        thrown.expect(IllegalArgumentException.class);
+        new ObjectId("", "object");
+    }
+
+    @Test
+    public void nullObjectNameNotAllowed() {
+        thrown.expect(NullPointerException.class);
+        new ObjectId("bucket", null);
+    }
+
+    @Test
+    public void emptyObjectNameNotAllowed() {
+        thrown.expect(IllegalArgumentException.class);
+        new ObjectId("bucket", "");
+    }
+
+    @Test
+    public void slashObjectNameNotAllowed() {
+        thrown.expect(IllegalArgumentException.class);
+        new ObjectId("bucket", "/");
+    }
+
+    @Test
+    public void checkConsistentHashing() {
+        ObjectId id1 = new ObjectId("bucket", "object");
+        ObjectId id2 = new ObjectId("gs://bucket/object");
+        assertTrue(id1.equals(id2));
+        assertTrue(id1.hashCode() == id2.hashCode());
+    }
+}