Moving apps search related logic into a custom layout file

This will allow derivative projects to easily change the search behavior
by simply overriding the xml file

Bug: 37616877
Change-Id: Ib8d6a2dab06819a52611e9a3d97c70c5a49bbf97

src/com/android/launcher3/allapps/search/DefaultAppSearchAlgorithm.java

@@ -0,0 +1,136 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * 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.android.launcher3.allapps.search;
+
+import android.os.Handler;
+
+import com.android.launcher3.AppInfo;
+import com.android.launcher3.util.ComponentKey;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * The default search implementation.
+ */
+public class DefaultAppSearchAlgorithm {
+
+    private final List<AppInfo> mApps;
+    protected final Handler mResultHandler;
+
+    public DefaultAppSearchAlgorithm(List<AppInfo> apps) {
+        mApps = apps;
+        mResultHandler = new Handler();
+    }
+
+    public void cancel(boolean interruptActiveRequests) {
+        if (interruptActiveRequests) {
+            mResultHandler.removeCallbacksAndMessages(null);
+        }
+    }
+
+    public void doSearch(final String query,
+            final AllAppsSearchBarController.Callbacks callback) {
+        final ArrayList<ComponentKey> result = getTitleMatchResult(query);
+        mResultHandler.post(new Runnable() {
+
+            @Override
+            public void run() {
+                callback.onSearchResult(query, result);
+            }
+        });
+    }
+
+    protected ArrayList<ComponentKey> getTitleMatchResult(String query) {
+        // Do an intersection of the words in the query and each title, and filter out all the
+        // apps that don't match all of the words in the query.
+        final String queryTextLower = query.toLowerCase();
+        final ArrayList<ComponentKey> result = new ArrayList<>();
+        for (AppInfo info : mApps) {
+            if (matches(info, queryTextLower)) {
+                result.add(info.toComponentKey());
+            }
+        }
+        return result;
+    }
+
+    protected boolean matches(AppInfo info, String query) {
+        int queryLength = query.length();
+
+        String title = info.title.toString();
+        int titleLength = title.length();
+
+        if (titleLength < queryLength || queryLength <= 0) {
+            return false;
+        }
+
+        int lastType;
+        int thisType = Character.UNASSIGNED;
+        int nextType = Character.getType(title.codePointAt(0));
+
+        int end = titleLength - queryLength;
+        for (int i = 0; i <= end; i++) {
+            lastType = thisType;
+            thisType = nextType;
+            nextType = i < (titleLength - 1) ?
+                    Character.getType(title.codePointAt(i + 1)) : Character.UNASSIGNED;
+            if (isBreak(thisType, lastType, nextType) &&
+                    title.substring(i, i + queryLength).equalsIgnoreCase(query)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Returns true if the current point should be a break point. Following cases
+     * are considered as break points:
+     *      1) Any non space character after a space character
+     *      2) Any digit after a non-digit character
+     *      3) Any capital character after a digit or small character
+     *      4) Any capital character before a small character
+     */
+    protected boolean isBreak(int thisType, int prevType, int nextType) {
+        switch (thisType) {
+            case Character.UPPERCASE_LETTER:
+                if (nextType == Character.UPPERCASE_LETTER) {
+                    return true;
+                }
+                // Follow through
+            case Character.TITLECASE_LETTER:
+                // Break point if previous was not a upper case
+                return prevType != Character.UPPERCASE_LETTER;
+            case Character.LOWERCASE_LETTER:
+                // Break point if previous was not a letter.
+                return prevType > Character.OTHER_LETTER || prevType <= Character.UNASSIGNED;
+            case Character.DECIMAL_DIGIT_NUMBER:
+            case Character.LETTER_NUMBER:
+            case Character.OTHER_NUMBER:
+                // Break point if previous was not a number
+                return !(prevType == Character.DECIMAL_DIGIT_NUMBER
+                        || prevType == Character.LETTER_NUMBER
+                        || prevType == Character.OTHER_NUMBER);
+            case Character.MATH_SYMBOL:
+            case Character.CURRENCY_SYMBOL:
+            case Character.OTHER_PUNCTUATION:
+            case Character.DASH_PUNCTUATION:
+                // Always a break point for a symbol
+                return true;
+            default:
+                return false;
+        }
+    }
+}