initial code

Signed-off-by: radai-rosenblatt <radai.rosenblatt@gmail.com>

.gitignore

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+#gradle artifacts
+.gradle/
+build/
+
+#IDEA artifacts
+out/
+.idea/
+*.iml

CONTRIBUTING.md

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+Contribution Agreement
+======================
+
+As a contributor, you represent that the code you submit is your
+original work or that of your employer (in which case you represent you
+have the right to bind your employer).  By submitting code, you (and, if
+applicable, your employer) are licensing the submitted code to LinkedIn
+and the open source community subject to the BSD 2-Clause license. 
+
+Responsible Disclosure of Security Vulnerabilities
+==================================================
+
+Please do not file reports on Github for security issues.
+Please review the guidelines at https://www.linkedin.com/help/linkedin/answer/62924/security-vulnerabilities?lang=en

LICENSE

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+BSD 2-CLAUSE LICENSE
+
+Copyright 2018 LinkedIn Corporation.
+All Rights Reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+1. Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+
+2. 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.
+
+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
+HOLDER 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.

NOTICE

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+Copyright 2018 LinkedIn Corporation
+All Rights Reserved.
+
+Licensed under the BSD 2-Clause License (the "License").
+See License in the project root for license information.

README.md

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+Avro-Util
+=========
+
+A collection of utilities and helper code to allow java projects to work
+across a wide version of avro versions
+
+### Background ###
+
+Apache Avro is a widely used serialization format.
+
+Unfortunately it is not always possible to write java code that "just works" 
+across multiple versions of avro, as there have been breaking changes to both 
+the API and wire format.
+
+This project provides utility code to enable java developers to write code 
+that is compatible across a wide range of avro versions 

avro-migration-helper/build.gradle

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+/*
+ * Copyright 2018 LinkedIn Corp.
+ * Licensed under the BSD 2-Clause License (the "License").

+ * See License in the project root for license information.
+ */
+
+apply plugin: 'java-library'
+
+dependencies {
+
+  compileOnly ('org.apache.avro:avro:1.4.1') {
+    exclude group: "org.mortbay.jetty"
+    exclude group: "org.apache.velocity"
+    exclude group: "commons-lang"
+    exclude group: "org.jboss.netty"
+    exclude group: "com.thoughtworks.paranamer", module: "paranamer-ant"
+  }
+  //when run with #avro17
+  //compileOnly 'org.apache.avro:avro-compiler:1.7.7'
+
+  compile 'org.json:json:20170516'
+
+  testCompile ('org.apache.avro:avro:1.4.1') {
+    exclude group: "org.mortbay.jetty"
+    exclude group: "org.apache.velocity"
+    exclude group: "commons-lang"
+    exclude group: "org.jboss.netty"
+    exclude group: "com.thoughtworks.paranamer", module: "paranamer-ant"
+  }
+  //when run with #avro17
+  //compileOnly 'org.apache.avro:avro-compiler:1.7.7'
+  testCompile 'org.testng:testng:6.14.3'
+  testCompile 'commons-io:commons-io:2.6'
+  testCompile 'org.skyscreamer:jsonassert:1.5.0'
+  testCompile 'net.openhft:compiler:2.3.1'
+}

avro-migration-helper/src/main/java/com/linkedin/avro/compatibility/AbstractAvroFactory.java

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+/*
+ * Copyright 2018 LinkedIn Corp.
+ * Licensed under the BSD 2-Clause License (the "License").

+ * See License in the project root for license information.
+ */
+
+package com.linkedin.avro.compatibility;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.stream.Collectors;
+import org.apache.avro.Schema;
+
+
+//package private ON PURPOSE
+abstract class AbstractAvroFactory implements AvroFactory {
+  //common fields
+  protected final Constructor _enumSymbolCtr;
+  protected final Constructor _fixedCtr;
+
+  //common compiler fields
+  protected Constructor _specificCompilerCtr;
+  protected Method _compilerEnqueueMethod;
+  protected Method _compilerCompileMethod;
+  protected Field _outputFilePathField;
+  protected Field _outputFileContentsField;
+
+  public AbstractAvroFactory(Constructor enumSymbolCtr, Constructor fixedCtr) throws Exception {
+    _enumSymbolCtr = enumSymbolCtr;
+    _fixedCtr = fixedCtr;
+  }
+
+  @Override
+  public Collection<AvroGeneratedSourceCode> compile(Collection<Schema> toCompile, AvroVersion compatibilityTarget) {
+    if (toCompile == null || toCompile.isEmpty()) {
+      return Collections.emptyList();
+    }
+    Iterator<Schema> schemaIter = toCompile.iterator();
+    Schema first = schemaIter.next();
+    try {
+      Object compilerInstance = getCompilerInstance(first, compatibilityTarget);
+
+      while (schemaIter.hasNext()) {
+        _compilerEnqueueMethod.invoke(compilerInstance, schemaIter.next());
+      }
+      Collection<?> outputFiles = (Collection<?>) _compilerCompileMethod.invoke(compilerInstance);
+      List<AvroGeneratedSourceCode> translated = outputFiles.stream()
+          .map(o -> new AvroGeneratedSourceCode(getPath(o), getContents(o)))
+          .collect(Collectors.toList());
+
+      return transform(translated, compatibilityTarget);
+    } catch (UnsupportedOperationException e) {
+      throw e; //as-is
+    } catch (Exception e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
+  protected Object getCompilerInstance(Schema firstSchema, AvroVersion compatibilityTarget) throws Exception {
+    return _specificCompilerCtr.newInstance(firstSchema);
+  }
+
+  protected List<AvroGeneratedSourceCode> transform(List<AvroGeneratedSourceCode> avroCodegenOutput, AvroVersion compatibilityLevel) {
+    return avroCodegenOutput; //nop
+  }
+
+  protected String getPath(Object shouldBeOutputFile) {
+    try {
+      return (String) _outputFilePathField.get(shouldBeOutputFile);
+    } catch (Exception e) {
+      throw new IllegalStateException("cant extract path from avro OutputFile", e);
+    }
+  }
+
+  protected String getContents(Object shouldBeOutputFile) {
+    try {
+      return (String) _outputFileContentsField.get(shouldBeOutputFile);
+    } catch (Exception e) {
+      throw new IllegalStateException("cant extract contents from avro OutputFile", e);
+    }
+  }
+}