Add util method in ngramcontext for context array
Change-Id: I2e3e2ac7706be50ed2055b0c69b30e25a516a879
diff --git a/java/src/com/android/inputmethod/latin/NgramContext.java b/java/src/com/android/inputmethod/latin/NgramContext.java
index 53bec6e..c935158 100644
--- a/java/src/com/android/inputmethod/latin/NgramContext.java
+++ b/java/src/com/android/inputmethod/latin/NgramContext.java
@@ -146,6 +146,32 @@
: TextUtils.join(CONTEXT_SEPARATOR, terms);
}
+ /**
+ * Extracts the previous words context.
+ *
+ * @return a String array with the previous words.
+ */
+ public String[] extractPrevWordsContextArray() {
+ final ArrayList<String> prevTermList = new ArrayList<>();
+ for (int i = mPrevWordsInfo.length - 1; i >= 0; --i) {
+ if (mPrevWordsInfo[i] != null && mPrevWordsInfo[i].isValid()) {
+ final NgramContext.WordInfo wordInfo = mPrevWordsInfo[i];
+ if (wordInfo.mIsBeginningOfSentence) {
+ prevTermList.add(BEGINNING_OF_SENTENCE_TAG);
+ } else {
+ final String term = wordInfo.mWord.toString();
+ if (!term.isEmpty()) {
+ prevTermList.add(term);
+ }
+ }
+ }
+ }
+ final String[] contextStringArray = prevTermList.size() == 0 ?
+ new String[] { BEGINNING_OF_SENTENCE_TAG }
+ : prevTermList.toArray(new String[prevTermList.size()]);
+ return contextStringArray;
+ }
+
public boolean isValid() {
return mPrevWordsCount > 0 && mPrevWordsInfo[0].isValid();
}
diff --git a/tests/src/com/android/inputmethod/latin/NgramContextTests.java b/tests/src/com/android/inputmethod/latin/NgramContextTests.java
index ab1819d..97143a3 100644
--- a/tests/src/com/android/inputmethod/latin/NgramContextTests.java
+++ b/tests/src/com/android/inputmethod/latin/NgramContextTests.java
@@ -64,4 +64,43 @@
ngramContext_b_a.getNextNgramContext(new WordInfo("c"));
assertEquals("c", ngramContext_c_bos.getNthPrevWord(1));
}
+
+ public void testExtractPrevWordsContextTest() {
+ final NgramContext ngramContext_bos =
+ new NgramContext(WordInfo.BEGINNING_OF_SENTENCE_WORD_INFO);
+ assertEquals("<S>", ngramContext_bos.extractPrevWordsContext());
+ final NgramContext ngramContext_a = new NgramContext(new WordInfo("a"));
+ final NgramContext ngramContext_b_a =
+ ngramContext_a.getNextNgramContext(new WordInfo("b"));
+ assertEquals("b", ngramContext_b_a.getNthPrevWord(1));
+ assertEquals("a", ngramContext_b_a.getNthPrevWord(2));
+ assertEquals("a b", ngramContext_b_a.extractPrevWordsContext());
+
+ final NgramContext ngramContext_bos_b =
+ ngramContext_b_a.getNextNgramContext(WordInfo.BEGINNING_OF_SENTENCE_WORD_INFO);
+ assertTrue(ngramContext_bos_b.isBeginningOfSentenceContext());
+ assertEquals("b", ngramContext_bos_b.getNthPrevWord(2));
+ assertEquals("a b <S>", ngramContext_bos_b.extractPrevWordsContext());
+ }
+
+ public void testExtractPrevWordsContextArray() {
+ final NgramContext ngramContext_bos =
+ new NgramContext(WordInfo.BEGINNING_OF_SENTENCE_WORD_INFO);
+ assertEquals("<S>", ngramContext_bos.extractPrevWordsContext());
+ final NgramContext ngramContext_a = new NgramContext(new WordInfo("a"));
+ final NgramContext ngramContext_b_a =
+ ngramContext_a.getNextNgramContext(new WordInfo("b"));
+ assertEquals("b", ngramContext_b_a.getNthPrevWord(1));
+ assertEquals("a", ngramContext_b_a.getNthPrevWord(2));
+ assertEquals("a", ngramContext_b_a.extractPrevWordsContextArray()[0]);
+ assertEquals("b", ngramContext_b_a.extractPrevWordsContextArray()[1]);
+
+ final NgramContext ngramContext_bos_b =
+ ngramContext_b_a.getNextNgramContext(WordInfo.BEGINNING_OF_SENTENCE_WORD_INFO);
+ assertTrue(ngramContext_bos_b.isBeginningOfSentenceContext());
+ assertEquals("b", ngramContext_bos_b.getNthPrevWord(2));
+ assertEquals("a", ngramContext_bos_b.extractPrevWordsContextArray()[0]);
+ assertEquals("b", ngramContext_bos_b.extractPrevWordsContextArray()[1]);
+ assertEquals("<S>", ngramContext_bos_b.extractPrevWordsContextArray()[2]);
+ }
}