Supply a Preconditions in common location

This is a follow-up to #798, which handles `Preconditions` similarly to
`ToStringBuilder`.

See #742 for detailed discussion.

CHANGELOG.md

@@ -12,7 +12,9 @@ Breaking API changes:
   * The name field in WorkspaceFolder is no longer optional according to the specification.
     * See [#741](https://github.com/eclipse-lsp4j/lsp4j/issues/741) for detailed discussion.
   * The LSP4J generator when applied to `@JsonRpcData` annotated classes generates a dependency on package `org.eclipse.lsp4j.jsonrpc.util` in the `org.eclipse.lsp4j.jsonrpc` bundle.
-    * This removes the implied requirement in LSP4J 0.21.0 that there is a class called `ToStringBuilder` in a sub-package called `util`.
+    * This removes the implied requirement in LSP4J 0.21.0 that there are classes called `ToStringBuilder` and `Preconditions` in a sub-package called `util`;
+      instead, the generator now uses classes `ToStringBuilder` and `Preconditions` in package `org.eclipse.lsp4j.jsonrpc.util`.
+    * Duplicate classes `ToStringBuilder` and `Preconditions` have been removed from `org.eclipse.lsp4j.util` and `org.eclipse.lsp4j.debug.util` packages.
     * See [#742](https://github.com/eclipse-lsp4j/lsp4j/issues/742) for detailed discussion.
 
 Nightly japicmp report: <https://download.eclipse.org/lsp4j/builds/main/japicmp-report/>

org.eclipse.lsp4j.generator/src/main/java/org/eclipse/lsp4j/generator/JsonRpcDataProcessor.xtend

@@ -172,10 +172,7 @@ class JsonRpcDataProcessor extends AbstractClassProcessor {
 	}
 
 	private def getPreconditionsUtil(Type type, extension TransformationContext context) {
-		if (type.qualifiedName.startsWith('org.eclipse.lsp4j.debug'))
-			newTypeReference('org.eclipse.lsp4j.debug.util.Preconditions')
-		else
-			newTypeReference('org.eclipse.lsp4j.util.Preconditions')
+		newTypeReference('org.eclipse.lsp4j.jsonrpc.util.Preconditions')
 	}
 
 }

org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/Preconditions.java → org.eclipse.lsp4j.jsonrpc/src/main/java/org/eclipse/lsp4j/jsonrpc/util/Preconditions.java

@@ -9,7 +9,7 @@
  * 
  * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
  ******************************************************************************/
-package org.eclipse.lsp4j.util;
+package org.eclipse.lsp4j.jsonrpc.util;
 
 /**
  * Utilities for checking method and constructor arguments.

org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/Protocol.xtend

@@ -34,8 +34,8 @@ import org.eclipse.lsp4j.jsonrpc.messages.Either
 import org.eclipse.lsp4j.jsonrpc.messages.Either3
 import org.eclipse.lsp4j.jsonrpc.messages.ResponseErrorCode
 import org.eclipse.lsp4j.jsonrpc.messages.Tuple
+import org.eclipse.lsp4j.jsonrpc.util.Preconditions
 import org.eclipse.lsp4j.jsonrpc.validation.NonNull
-import org.eclipse.lsp4j.util.Preconditions
 
 @JsonRpcData
 class DynamicRegistrationCapabilities {

org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/DocumentSymbols.java

@@ -16,6 +16,7 @@
 import java.util.Queue;
 
 import org.eclipse.lsp4j.DocumentSymbol;
+import org.eclipse.lsp4j.jsonrpc.util.Preconditions;
 
 /**
  * Utilities for {@link DocumentSymbol document symbols}.

org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/Positions.java

@@ -12,6 +12,7 @@
 package org.eclipse.lsp4j.util;
 
 import org.eclipse.lsp4j.Position;
+import org.eclipse.lsp4j.jsonrpc.util.Preconditions;
 
 /**
  * Utilities for the {@link Position}.

org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/util/Ranges.java

@@ -13,6 +13,7 @@
 
 import org.eclipse.lsp4j.Position;
 import org.eclipse.lsp4j.Range;
+import org.eclipse.lsp4j.jsonrpc.util.Preconditions;
 
 /**
  * Utility class for {@link Range}.