Merge Java util package to github.

1 files changed, 259 insertions, 0 deletions

diff --git a/java/util/src/main/java/com/google/protobuf/util/FieldMaskTree.java b/java/util/src/main/java/com/google/protobuf/util/FieldMaskTree.java
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index 00000000..dc2f4b84
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+++ b/java/util/src/main/java/com/google/protobuf/util/FieldMaskTree.java
@@ -0,0 +1,259 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package com.google.protobuf.util;
+
+import com.google.protobuf.Descriptors.Descriptor;
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import com.google.protobuf.FieldMask;
+import com.google.protobuf.Message;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map.Entry;
+import java.util.TreeMap;
+import java.util.logging.Logger;
+
+/**
+ * A tree representation of a FieldMask. Each leaf node in this tree represent
+ * a field path in the FieldMask.
+ *
+ * <p>For example, FieldMask "foo.bar,foo.baz,bar.baz" as a tree will be:
+ * <pre>
+ *   [root] -+- foo -+- bar
+ *           |       |
+ *           |       +- baz
+ *           |
+ *           +- bar --- baz
+ * </pre>
+ *
+ * <p>By representing FieldMasks with this tree structure we can easily convert
+ * a FieldMask to a canonical form, merge two FieldMasks, calculate the
+ * intersection to two FieldMasks and traverse all fields specified by the
+ * FieldMask in a message tree.
+ */
+class FieldMaskTree {
+  private static final Logger logger =
+      Logger.getLogger(FieldMaskTree.class.getName());
+  
+  private static final String FIELD_PATH_SEPARATOR_REGEX = "\\."; 
+
+  private static class Node {
+    public TreeMap<String, Node> children = new TreeMap<String, Node>();
+  }
+
+  private final Node root = new Node();
+
+  /** Creates an empty FieldMaskTree. */
+  public FieldMaskTree() {}
+  
+  /** Creates a FieldMaskTree for a given FieldMask. */
+  public FieldMaskTree(FieldMask mask) {
+    mergeFromFieldMask(mask);
+  }
+  
+  @Override
+  public String toString() {
+    return FieldMaskUtil.toString(toFieldMask());
+  }
+
+  /**
+   * Adds a field path to the tree. In a FieldMask, every field path matches the
+   * specified field as well as all its sub-fields. For example, a field path
+   * "foo.bar" matches field "foo.bar" and also "foo.bar.baz", etc. When adding
+   * a field path to the tree, redundant sub-paths will be removed. That is,
+   * after adding "foo.bar" to the tree, "foo.bar.baz" will be removed if it
+   * exists, which will turn the tree node for "foo.bar" to a leaf node.
+   * Likewise, if the field path to add is a sub-path of an existing leaf node,
+   * nothing will be changed in the tree.
+   */
+  public FieldMaskTree addFieldPath(String path) {
+    String[] parts = path.split(FIELD_PATH_SEPARATOR_REGEX);
+    if (parts.length == 0) {
+      return this;
+    }
+    Node node = root;
+    boolean createNewBranch = false;
+    // Find the matching node in the tree.
+    for (String part : parts) {
+      // Check whether the path matches an existing leaf node.
+      if (!createNewBranch && node != root && node.children.isEmpty()) {
+        // The path to add is a sub-path of an existing leaf node.
+        return this;
+      }
+      if (node.children.containsKey(part)) {
+        node = node.children.get(part);
+      } else {
+        createNewBranch = true;
+        Node tmp = new Node();
+        node.children.put(part, tmp);
+        node = tmp;
+      }
+    }
+    // Turn the matching node into a leaf node (i.e., remove sub-paths).
+    node.children.clear();
+    return this;
+  }
+  
+  /**
+   * Merges all field paths in a FieldMask into this tree.
+   */
+  public FieldMaskTree mergeFromFieldMask(FieldMask mask) {
+    for (String path : mask.getPathsList()) {
+      addFieldPath(path);
+    }
+    return this;
+  }
+
+  /** Converts this tree to a FieldMask. */
+  public FieldMask toFieldMask() {
+    if (root.children.isEmpty()) {
+      return FieldMask.getDefaultInstance();
+    }
+    List<String> paths = new ArrayList<String>();
+    getFieldPaths(root, "", paths);
+    return FieldMask.newBuilder().addAllPaths(paths).build();
+  }
+
+  /** Gathers all field paths in a sub-tree. */
+  private void getFieldPaths(Node node, String path, List<String> paths) {
+    if (node.children.isEmpty()) {
+      paths.add(path);
+      return;
+    }
+    for (Entry<String, Node> entry : node.children.entrySet()) {
+      String childPath = path.isEmpty()
+          ? entry.getKey() : path + "." + entry.getKey();
+      getFieldPaths(entry.getValue(), childPath, paths);
+    }
+  }
+
+  /**
+   * Adds the intersection of this tree with the given {@code path} to
+   * {@code output}.
+   */
+  public void intersectFieldPath(String path, FieldMaskTree output) {
+    if (root.children.isEmpty()) {
+      return;
+    }
+    String[] parts = path.split(FIELD_PATH_SEPARATOR_REGEX);
+    if (parts.length == 0) {
+      return;
+    }
+    Node node = root;
+    for (String part : parts) {
+      if (node != root && node.children.isEmpty()) {
+        // The given path is a sub-path of an existing leaf node in the tree.
+        output.addFieldPath(path);
+        return;
+      }
+      if (node.children.containsKey(part)) {
+        node = node.children.get(part);
+      } else {
+        return;
+      }
+    }
+    // We found a matching node for the path. All leaf children of this matching
+    // node is in the intersection.
+    List<String> paths = new ArrayList<String>();
+    getFieldPaths(node, path, paths);
+    for (String value : paths) {
+      output.addFieldPath(value);
+    }
+  }
+
+  /**
+   * Merges all fields specified by this FieldMaskTree from {@code source} to
+   * {@code destination}.
+   */
+  public void merge(Message source, Message.Builder destination,
+      FieldMaskUtil.MergeOptions options) {
+    if (source.getDescriptorForType() != destination.getDescriptorForType()) {
+      throw new IllegalArgumentException(
+          "Cannot merge messages of different types.");
+    }
+    if (root.children.isEmpty()) {
+      return;
+    }
+    merge(root, "", source, destination, options);
+  }
+
+  /** Merges all fields specified by a sub-tree from {@code source} to
+   * {@code destination}.
+   */
+  private void merge(Node node, String path, Message source,
+      Message.Builder destination, FieldMaskUtil.MergeOptions options) {
+    assert source.getDescriptorForType() == destination.getDescriptorForType();
+    
+    Descriptor descriptor = source.getDescriptorForType();
+    for (Entry<String, Node> entry : node.children.entrySet()) {
+      FieldDescriptor field =
+          descriptor.findFieldByName(entry.getKey());
+      if (field == null) {
+        logger.warning("Cannot find field \"" + entry.getKey()
+            + "\" in message type " + descriptor.getFullName());
+        continue;
+      }
+      if (!entry.getValue().children.isEmpty()) {
+        if (field.isRepeated()
+            || field.getJavaType() != FieldDescriptor.JavaType.MESSAGE) {
+          logger.warning("Field \"" + field.getFullName() + "\" is not a "
+              + "singluar message field and cannot have sub-fields.");
+          continue;
+        }
+        String childPath = path.isEmpty()
+            ? entry.getKey() : path + "." + entry.getKey();
+        merge(entry.getValue(), childPath, (Message) source.getField(field),
+            destination.getFieldBuilder(field), options);
+        continue;
+      }
+      if (field.isRepeated()) {
+        if (options.replaceRepeatedFields()) {
+          destination.setField(field, source.getField(field));
+        } else {
+          for (Object element : (List) source.getField(field)) {
+            destination.addRepeatedField(field, element);
+          }
+        }
+      } else {
+        if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+          if (options.replaceMessageFields()) {
+            destination.setField(field, source.getField(field));
+          } else {
+            destination.getFieldBuilder(field).mergeFrom(
+                (Message) source.getField(field));
+          }
+        } else {
+          destination.setField(field, source.getField(field));
+        }
+      }
+    }
+  }
+}