PathExtraction initinal implementaion

.gitignore

@@ -0,0 +1,8 @@
+.gradle/
+.idea/
+build
+gradle/
+gradlew
+gradlew.bat
+out/
+ion-c

README.md

@@ -2,6 +2,90 @@
 
 Ion Path Extraction API aims to combine the convenience of a DOM API with the speed of a streaming API.
 
+The traditional streaming and DOM APIs force the user to choose between speed and convenience, respectively. 
+Path extraction APIs aim to combine the two by allowing the user to register paths into the data using just a 
+few lines of code and receive callbacks during stream processing when any of those paths is matched. This allows 
+the Ion reader to plan the most efficient traversal over the data without requiring further manual interaction 
+from the user. For example, there is no reason to step in to containers which could not possibly match one of 
+the search paths. When encoded in binary Ion, the resulting skip is a seek forward in the input stream, which 
+is inexpensive relative to the cost of parsing (and in the case of a DOM, materializing) the skipped value.
+
+## Usage 
+Path extractor works in two phases: 
+1. Configuration 
+2. Notification  
+
+### Search Paths
+A `SearchPath` is a path provided to the extractor for matching. It's composed of a list of `PathComponent`s 
+which can be one of: 
+* Wildcard: matches all values
+* Index: match the value at that index 
+* Text: match all values whose field names are equivalent to that text
+
+Some examples: 
+```
+data on reader: {foo: ["foo1", "foo2"] , bar: "myBarValue"}
+
+(foo 0) - matches "foo1"
+(1)     - matches "myBarValue"
+(*)     - matches ["foo1", "foo2"] and "myBarValue"
+()      - matches {foo: ["foo1", "foo2"] , bar: "myBarValue"}
+```
+
+### Configuration  
+The configuration phase involves building a `PathExtractor` instance through the `PathExtractorBuilder` by setting its 
+configuration options and registering its search paths. The built `PathExtractor` can be reused over many `IonReader`s.
+
+example: 
+
+```java 
+PathExtractorBuilder.standard()
+                    .withMatchCaseInsensitive(true) 
+                    .register("(foo)", (reader) -> { ... })
+                    .build()
+``` 
+
+see `PathExtractorBuilder` javadoc for more information on configuration options and search path registration. 
+
+### Notification  
+Each time the `PathExtractor` encounters a value that matches a registered search path it will invoke the respective 
+callback passing the reader positioned at the current value. See `PathExtractorBuilder#register` methods for more 
+information on the callback contract.
+
+### Examples: 
+
+```java
+// Capture all matched values into a List
+final IonSystem ion = IonSystemBuilder.standard().build();
+
+final List<IonValue> list = new ArrayList<>();
+final Function<IonReader, Integer> callback = (reader) -> {
+    IonValue ionValue = ion.newValue(reader);
+    list.add(ionValue);
+
+    return 0;
+};
+
+final PathExtractor pathExtractor = PathExtractorBuilder.standard()
+    .register("(foo)", callback)
+    .register("(bar)", callback)
+    .register("(baz 1)", callback)
+    .build();
+
+IonReader ionReader = ion.newReader("{foo: 1}"
+    + "{bar: 2}"
+    + "{baz: [10,20,30,40]}"
+    + "{other: 99}"
+);
+
+pathExtractor.match(ionReader);
+
+// list will contain 1, 2 and 20
+```
+
+## Ion Developer information
+See the developer guide on: http://amzn.github.io/ion-docs/guides/path-extractor-guide.html
+
 ## License
 
 This library is licensed under the Apache 2.0 License. 

build.gradle

@@ -0,0 +1,72 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. 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.
+ * A copy of the License is located at:
+ *
+ *     http://aws.amazon.com/apache2.0/
+ *
+ * or in the "license" file accompanying this file. This file 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.
+ */
+
+buildscript {
+    ext.ionVersion = "1.2.+"
+    ext.kotlin_version = "1.2.+"
+    ext.junitVersion = "5.3.+"
+
+    repositories {
+        mavenCentral()
+    }
+
+    dependencies {
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+    }
+}
+
+apply plugin: "java"
+apply plugin: "kotlin"
+
+group 'software.amazon.ion'
+version '1.0-SNAPSHOT'
+
+sourceCompatibility = 1.8
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    compile "software.amazon.ion:ion-java:$ionVersion"
+
+    // using kotlin to make tests less verbose
+    testCompile "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
+    testCompile "org.jetbrains.kotlin:kotlin-test-junit:$kotlin_version"
+
+    // JUnit 5
+    testCompile "org.junit.jupiter:junit-jupiter-api:$junitVersion"
+    testCompile "org.junit.jupiter:junit-jupiter-params:$junitVersion"
+    testRuntime "org.junit.jupiter:junit-jupiter-engine:$junitVersion"
+}
+
+tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).all {
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+}
+
+apply plugin: 'checkstyle'
+checkstyle {
+    toolVersion = "8.12"
+    ignoreFailures = false
+    maxWarnings = 0
+    maxErrors = 0
+    configDir = file("$rootProject.projectDir/config/checkstyle")
+}
+tasks.withType(Checkstyle) {
+    reports {
+        xml.enabled = false
+        html.enabled = true
+    }
+}

config/README.md

@@ -0,0 +1,2 @@
+# Configuration
+Project development configuration files, for example code style and checkstyle settings used on all modules