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Fix typos and improve naming consistency in "File-based Indexes" chapter.

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Inego 2018-04-09 19:39:32 +07:00
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basics/indexing_and_psi_stubs/file_based_indexes.md
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@ -12,25 +12,25 @@ The value is arbitrary data which is associated with the key in the index.
*Example:* in the word index the value is a mask indicating in which context the word occurs (code, string literal or comment).
In the simplest case, when we only need to know in what files some data occurs, the value has type `Void` and is not stored in the index.
In the simplest case, when we only need to know in what files some data is present, the value has type `Void` and is not stored in the index.
When the index implementation indexes a file, it receives the content of a file and returns a map from the keys found in the file to the associated values.
When you access the index, you specify the key that you're interested in and get back the list of files in which the key occurs and the value associated with each file.
## Implementing a file based index
## Implementing a file-based index
A fairly simple file-based index implementation is the [UI Designer bound forms index](upsource:///plugins/ui-designer/src/com/intellij/uiDesigner/binding/FormClassIndex.java). Refer to it as an example to understand this topic better.
Each specific index implementation is a class extending [FileBasedIndexExtension](upsource:///platform/indexing-api/src/com/intellij/util/indexing/FileBasedIndexExtension.java). A file based index should be registered in the `<fileBasedIndex>` extension point.
Each specific index implementation is a class extending [FileBasedIndexExtension](upsource:///platform/indexing-api/src/com/intellij/util/indexing/FileBasedIndexExtension.java). A file-based index should be registered in the `<fileBasedIndex>` extension point.
The implementation of a file based contains of the following main parts:
An implementation of a file-based index consists of the following main parts:
* `getIndexer()` returns the indexer class, which is is responsible for actually building a set of key/value pairs based on the file content.
* `getKeyDescriptor()` returns the key descriptor, which is responsible for comparing the keys and storing them in a serialized binary format.
* `getIndexer()` returns the indexer class actually responsible for building a set of key/value pairs based on file content.
* `getKeyDescriptor()` returns the key descriptor responsible for comparing keys and storing them in a serialized binary format.
Probably the most commonly used [`KeyDescriptor`](upsource:///platform/util/src/com/intellij/util/io/KeyDescriptor.java) implementation is [`EnumeratorStringDescriptor`](upsource:///platform/util/src/com/intellij/util/io/EnumeratorStringDescriptor.java) which is designed for storing identifiers in an efficient way.
* `getValueExternalizer()` returns the value serializer, which takes care of storing values in a serialized binary format.
* `getValueExternalizer()` returns the value serializer responsible for storing values in a serialized binary format.
* `getInputFilter()` allows to restrict the indexing only to a certain set of files.
* `getVersion()` returns the version of the index implementation. The index is automatically rebuilt if the current version differs from the version of the index implementation used to build the index.
@ -40,13 +40,13 @@ If you don't need to associate any value with the files (i.e. your value type is
> **Note** Please see `com.intellij.util.indexing.DebugAssertions` on how to enable additional debugging assertions during development to assert correct index implementation.
## Accessing a file based index
## Accessing a file-based index
Access to file based indexes is performed through the [FileBasedIndex](upsource:///platform/indexing-api/src/com/intellij/util/indexing/FileBasedIndex.java) class.
Access to file-based indexes is performed through the [FileBasedIndex](upsource:///platform/indexing-api/src/com/intellij/util/indexing/FileBasedIndex.java) class.
The following primary operations are supported:
* `getAllKeys()` and `processAllKeys()` allow to obtain the list of all keys found in files which are part of the specified project.
* `getAllKeys()` and `processAllKeys()` allow to obtain the list of all keys found in files which are a part of the specified project.
> **Note** The returned data is guaranteed to contain all keys found in up-to-date project content, but may also contain additional keys not currently found in the project.
@ -54,15 +54,15 @@ The following primary operations are supported:
* `getContainingFiles()` allows to obtain all files in which a specific key was encountered.
* `processValues()` allows to iterate though all files in which a specific key was encountered and to access the associated values at the same time.
> **Note** Nested index access is forbidden as it might lead to deadlock. Collect all necessary data from index A first, then process results while accessing index B.
> **Note** Nested index access is forbidden as it might lead to a deadlock. Collect all necessary data from index A first, then process results while accessing index B.
## Standard indexes
The *IntelliJ Platform* contains a number of the standard file-based indexes. The most useful indexes for plugin developers are:
The *IntelliJ Platform* contains a number of standard file-based indexes. The most useful indexes for plugin developers are:
* Word index
* File name index
Generally, the word index should be accessed indirectly, but using the helper methods in the [`PsiSearchHelper`](upsource:///platform/indexing-api/src/com/intellij/psi/search/PsiSearchHelper.java) class.
Generally, the word index should be accessed indirectly by using helper methods of the [`PsiSearchHelper`](upsource:///platform/indexing-api/src/com/intellij/psi/search/PsiSearchHelper.java) class.
The second index is [`FilenameIndex`](upsource:///platform/indexing-impl/src/com/intellij/psi/search/FilenameIndex.java). It provides a quick way to find all files matching a certain file name. [`FileTypeIndex`](upsource:///platform/indexing-impl/src/com/intellij/psi/search/FileTypeIndex.java) serves a similar goal: it allows to quickly find all files of a certain file type.