Properties

Properties

Properties()

Creates an empty property list with no default values.

Properties

Properties(initialCapacity: Int)

Creates an empty property list with no default values, and with an initial size accommodating the specified number of elements without the need to dynamically resize.

Properties

Properties(defaults: Properties!)

Creates an empty property list with the specified defaults.

clear

open fun clear(): Unit

Clears this hashtable so that it contains no keys.

clone

open fun clone(): Any

Creates a shallow copy of this hashtable. All the structure of the hashtable itself is copied, but the keys and values are not cloned. This is a relatively expensive operation.

compute

open fun compute(
    key: Any!, 
    remappingFunction: BiFunction<in Any!, in Any?, *>
): Any?

Attempts to compute a mapping for the specified key and its current mapped value (or null if there is no current mapping). For example, to either create or append a String msg to a value mapping:

<code>map.compute(key, (k, v) -&gt; (v == null) ? msg : v.concat(msg))</code>

If the remapping function returns null, the mapping is removed (or remains absent if initially absent). If the remapping function itself throws an (unchecked) exception, the exception is rethrown, and the current mapping is left unchanged.

The remapping function should not modify this map during computation.

This method will, on a best-effort basis, throw a java.util.ConcurrentModificationException if the remapping function modified this map during computation.

computeIfAbsent

open fun computeIfAbsent(
    key: Any!, 
    mappingFunction: Function<in Any!, *>
): Any!

If the specified key is not already associated with a value (or is mapped to null), attempts to compute its value using the given mapping function and enters it into this map unless null.

If the mapping function returns null, no mapping is recorded. If the mapping function itself throws an (unchecked) exception, the exception is rethrown, and no mapping is recorded. The most common usage is to construct a new object serving as an initial mapped value or memoized result, as in:

<code>map.computeIfAbsent(key, k -&gt; new Value(f(k)));
  </code>

Or to implement a multi-value map, Map<K,Collection<V>>, supporting multiple values per key:

<code>map.computeIfAbsent(key, k -&gt; new HashSet&lt;V&gt;()).add(v);
  </code>

The mapping function should not modify this map during computation.

This method will, on a best-effort basis, throw a java.util.ConcurrentModificationException if the mapping function modified this map during computation.

computeIfPresent

open fun computeIfPresent(
    key: Any!, 
    remappingFunction: BiFunction<in Any!, in Any, *>
): Any?

If the value for the specified key is present and non-null, attempts to compute a new mapping given the key and its current mapped value.

If the remapping function returns null, the mapping is removed. If the remapping function itself throws an (unchecked) exception, the exception is rethrown, and the current mapping is left unchanged.

The remapping function should not modify this map during computation.

This method will, on a best-effort basis, throw a java.util.ConcurrentModificationException if the remapping function modified this map during computation.

contains

open fun contains(value: Any!): Boolean

Tests if some key maps into the specified value in this hashtable. This operation is more expensive than the containsKey method.

Note that this method is identical in functionality to containsValue, (which is part of the Map interface in the collections framework).

containsKey

open fun containsKey(key: Any!): Boolean

Tests if the specified object is a key in this hashtable.

containsValue

open fun containsValue(value: Any!): Boolean

Returns true if this hashtable maps one or more keys to this value.

Note that this method is identical in functionality to contains (which predates the Map interface).

elements

open fun elements(): Enumeration<Any!>!

Returns an enumeration of the values in this hashtable. Use the Enumeration methods on the returned object to fetch the elements sequentially. If the hashtable is structurally modified while enumerating over the values then the results of enumerating are undefined.

equals

open fun equals(other: Any?): Boolean

Compares the specified Object with this Map for equality, as per the definition in the Map interface.

forEach

open fun forEach(action: BiConsumer<in Any!, in Any!>): Unit

Performs the given action for each entry in this map until all entries have been processed or the action throws an exception. Unless otherwise specified by the implementing class, actions are performed in the order of entry set iteration (if an iteration order is specified.) Exceptions thrown by the action are relayed to the caller.

get

open fun get(key: Any!): Any?

Returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.

More formally, if this map contains a mapping from a key k to a value v such that (key.equals(k)), then this method returns v; otherwise it returns null. (There can be at most one such mapping.)

getOrDefault

open fun getOrDefault(
    key: Any!, 
    defaultValue: Any!
): Any!

Returns the value to which the specified key is mapped, or defaultValue if this map contains no mapping for the key.

getProperty

open fun getProperty(key: String!): String!

Searches for the property with the specified key in this property list. If the key is not found in this property list, the default property list, and its defaults, recursively, are then checked. The method returns null if the property is not found.

getProperty

open fun getProperty(
    key: String!, 
    defaultValue: String!
): String!

Searches for the property with the specified key in this property list. If the key is not found in this property list, the default property list, and its defaults, recursively, are then checked. The method returns the default value argument if the property is not found.

hashCode

open fun hashCode(): Int

Returns the hash code value for this Map as per the definition in the Map interface.

isEmpty

open fun isEmpty(): Boolean

Tests if this hashtable maps no keys to values.

keys

open fun keys(): Enumeration<Any!>!

Returns an enumeration of the keys in this hashtable. Use the Enumeration methods on the returned object to fetch the keys sequentially. If the hashtable is structurally modified while enumerating over the keys then the results of enumerating are undefined.

list

open fun list(out: PrintStream!): Unit

Prints this property list out to the specified output stream. This method is useful for debugging.

list

open fun list(out: PrintWriter!): Unit

Prints this property list out to the specified output stream. This method is useful for debugging.

load

open fun load(inStream: InputStream!): Unit

Reads a property list (key and element pairs) from the input byte stream. The input stream is in a simple line-oriented format as specified in load(Reader) and is assumed to use the ISO 8859-1 character encoding; that is each byte is one Latin1 character. Characters not in Latin1, and certain special characters, are represented in keys and elements using Unicode escapes as defined in section {@jls 3.3} of The Java Language Specification.

The specified stream remains open after this method returns.

load

open fun load(reader: Reader!): Unit

Reads a property list (key and element pairs) from the input character stream in a simple line-oriented format.

Properties are processed in terms of lines. There are two kinds of line, natural lines and logical lines. A natural line is defined as a line of characters that is terminated either by a set of line terminator characters (\n or \r or \r\n) or by the end of the stream. A natural line may be either a blank line, a comment line, or hold all or some of a key-element pair. A logical line holds all the data of a key-element pair, which may be spread out across several adjacent natural lines by escaping the line terminator sequence with a backslash character \. Note that a comment line cannot be extended in this manner; every natural line that is a comment must have its own comment indicator, as described below. Lines are read from input until the end of the stream is reached.

A natural line that contains only white space characters is considered blank and is ignored. A comment line has an ASCII '#' or '!' as its first non-white space character; comment lines are also ignored and do not encode key-element information. In addition to line terminators, this format considers the characters space (' ', '\u005Cu0020'), tab ('\t', '\u005Cu0009'), and form feed ('\f', '\u005Cu000C') to be white space.

If a logical line is spread across several natural lines, the backslash escaping the line terminator sequence, the line terminator sequence, and any white space at the start of the following line have no affect on the key or element values. The remainder of the discussion of key and element parsing (when loading) will assume all the characters constituting the key and element appear on a single natural line after line continuation characters have been removed. Note that it is not sufficient to only examine the character preceding a line terminator sequence to decide if the line terminator is escaped; there must be an odd number of contiguous backslashes for the line terminator to be escaped. Since the input is processed from left to right, a non-zero even number of 2n contiguous backslashes before a line terminator (or elsewhere) encodes n backslashes after escape processing.

The key contains all of the characters in the line starting with the first non-white space character and up to, but not including, the first unescaped '=', ':', or white space character other than a line terminator. All of these key termination characters may be included in the key by escaping them with a preceding backslash character; for example,

\:\=

would be the two-character key ":=". Line terminator characters can be included using \r and \n escape sequences. Any white space after the key is skipped; if the first non-white space character after the key is '=' or ':', then it is ignored and any white space characters after it are also skipped. All remaining characters on the line become part of the associated element string; if there are no remaining characters, the element is the empty string "". Once the raw character sequences constituting the key and element are identified, escape processing is performed as described above.

As an example, each of the following three lines specifies the key "Truth" and the associated element value "Beauty":

Truth = Beauty
   Truth:Beauty
  Truth                    :Beauty
  

fruits                           apple, banana, pear, \
                                   cantaloupe, watermelon, \
                                   kiwi, mango
  

"apple, banana, pear, cantaloupe, watermelon, kiwi, mango"

As a third example, the line:

cheeses
  

Characters in keys and elements can be represented in escape sequences similar to those used for character and string literals (see sections {@jls 3.3} and {@jls 3.10.6} of The Java Language Specification). The differences from the character escape sequences and Unicode escapes used for characters and strings are:

• Octal escapes are not recognized.
• The character sequence \b does not represent a backspace character.
• The method does not treat a backslash character, \, before a non-valid escape character as an error; the backslash is silently dropped. For example, in a Java string the sequence "\z" would cause a compile time error. In contrast, this method silently drops the backslash. Therefore, this method treats the two character sequence "\b" as equivalent to the single character 'b'.
• Escapes are not necessary for single and double quotes; however, by the rule above, single and double quote characters preceded by a backslash still yield single and double quote characters, respectively.
• Only a single 'u' character is allowed in a Unicode escape sequence.

The specified stream remains open after this method returns.

loadFromXML

open fun loadFromXML(in: InputStream!): Unit

Loads all of the properties represented by the XML document on the specified input stream into this properties table.

The XML document must have the following DOCTYPE declaration:

<!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd">
  

An implementation is required to read XML documents that use the "UTF-8" or "UTF-16" encoding. An implementation may support additional encodings.

The specified stream is closed after this method returns.

merge

open fun merge(
    key: Any!, 
    value: Any, 
    remappingFunction: BiFunction<in Any, in Any, *>
): Any?

If the specified key is not already associated with a value or is associated with null, associates it with the given non-null value. Otherwise, replaces the associated value with the results of the given remapping function, or removes if the result is null. This method may be of use when combining multiple mapped values for a key. For example, to either create or append a String msg to a value mapping:

<code>map.merge(key, msg, String::concat)
  </code>

If the remapping function returns null, the mapping is removed. If the remapping function itself throws an (unchecked) exception, the exception is rethrown, and the current mapping is left unchanged.

The remapping function should not modify this map during computation.

This method will, on a best-effort basis, throw a java.util.ConcurrentModificationException if the remapping function modified this map during computation.

propertyNames

open fun propertyNames(): Enumeration<*>!

Returns an enumeration of all the keys in this property list, including distinct keys in the default property list if a key of the same name has not already been found from the main properties list.

put

open fun put(
    key: Any!, 
    value: Any!
): Any?

Maps the specified key to the specified value in this hashtable. Neither the key nor the value can be null.

The value can be retrieved by calling the get method with a key that is equal to the original key.

putAll

open fun putAll(from: Map<*, *>): Unit

Copies all of the mappings from the specified map to this hashtable. These mappings will replace any mappings that this hashtable had for any of the keys currently in the specified map.

putIfAbsent

open fun putIfAbsent(
    key: Any!, 
    value: Any!
): Any?

If the specified key is not already associated with a value (or is mapped to null) associates it with the given value and returns null, else returns the current value.

remove

open fun remove(key: Any!): Any?

Removes the key (and its corresponding value) from this hashtable. This method does nothing if the key is not in the hashtable.

remove

open fun remove(
    key: Any!, 
    value: Any!
): Boolean

Removes the entry for the specified key only if it is currently mapped to the specified value.

replace

open fun replace(
    key: Any!, 
    value: Any!
): Any?

Replaces the entry for the specified key only if it is currently mapped to some value.

replace

open fun replace(
    key: Any!, 
    oldValue: Any!, 
    newValue: Any!
): Boolean

Replaces the entry for the specified key only if currently mapped to the specified value.

replaceAll

open fun replaceAll(function: BiFunction<in Any!, in Any!, *>): Unit

Replaces each entry's value with the result of invoking the given function on that entry until all entries have been processed or the function throws an exception. Exceptions thrown by the function are relayed to the caller.

save

open fun save(
    out: OutputStream!, 
    comments: String!
): Unit

Deprecated: This method does not throw an IOException if an I/O error occurs while saving the property list. The preferred way to save a properties list is via the store(OutputStream out, String comments) method or the storeToXML(OutputStream os, String comment) method.

Calls the store(OutputStream out, String comments) method and suppresses IOExceptions that were thrown.

setProperty

open fun setProperty(
    key: String!, 
    value: String!
): Any!

Calls the Hashtable method put. Provided for parallelism with the getProperty method. Enforces use of strings for property keys and values. The value returned is the result of the Hashtable call to put.

store

open fun store(
    out: OutputStream!, 
    comments: String!
): Unit

Writes this property list (key and element pairs) in this Properties table to the output stream in a format suitable for loading into a Properties table using the load(InputStream) method.

Properties from the defaults table of this Properties table (if any) are not written out by this method.

This method outputs the comments, properties keys and values in the same format as specified in store(Writer), with the following differences:

• The stream is written using the ISO 8859-1 character encoding.
• Characters not in Latin-1 in the comments are written as \u005Cuxxxx for their appropriate unicode hexadecimal value xxxx.
• Characters less than \u005Cu0020 and characters greater than \u005Cu007E in property keys or values are written as \u005Cuxxxx for the appropriate hexadecimal value xxxx.

After the entries have been written, the output stream is flushed. The output stream remains open after this method returns.

store

open fun store(
    writer: Writer!, 
    comments: String!
): Unit

Writes this property list (key and element pairs) in this Properties table to the output character stream in a format suitable for using the load(Reader) method.

Properties from the defaults table of this Properties table (if any) are not written out by this method.

If the comments argument is not null, then an ASCII character, the comments string, and a line separator are first written to the output stream. Thus, the comments can serve as an identifying comment. Any one of a line feed ('\n'), a carriage return ('\r'), or a carriage return followed immediately by a line feed in comments is replaced by a line separator generated by the Writer and if the next character in comments is not character or character ! then an ASCII is written out after that line separator.

Next, a comment line is always written, consisting of an ASCII character, the current date and time (as if produced by the toString method of Date for the current time), and a line separator as generated by the Writer.

Then every entry in this Properties table is written out, one per line. For each entry the key string is written, then an ASCII =, then the associated element string. For the key, all space characters are written with a preceding \ character. For the element, leading space characters, but not embedded or trailing space characters, are written with a preceding \ character. The key and element characters , !, =, and : are written with a preceding backslash to ensure that they are properly loaded.

After the entries have been written, the output stream is flushed. The output stream remains open after this method returns.

storeToXML

open fun storeToXML(
    os: OutputStream!, 
    comment: String!
): Unit

Emits an XML document representing all of the properties contained in this table.

An invocation of this method of the form props.storeToXML(os, comment) behaves in exactly the same way as the invocation props.storeToXML(os, comment, "UTF-8");.

storeToXML

open fun storeToXML(
    os: OutputStream!, 
    comment: String!, 
    encoding: String!
): Unit

Emits an XML document representing all of the properties contained in this table, using the specified encoding.

The XML document will have the following DOCTYPE declaration:

<!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd">
  

If the specified comment is null then no comment will be stored in the document.

An implementation is required to support writing of XML documents that use the "UTF-8" or "UTF-16" encoding. An implementation may support additional encodings.

The specified stream remains open after this method returns.

This method behaves the same as storeToXML(java.io.OutputStream,java.lang.String,java.nio.charset.Charset) except that it will look up the charset using the given encoding name.

storeToXML

open fun storeToXML(
    os: OutputStream!, 
    comment: String!, 
    charset: Charset!
): Unit

Emits an XML document representing all of the properties contained in this table, using the specified encoding.

The XML document will have the following DOCTYPE declaration:

<!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd">
  

If the specified comment is null then no comment will be stored in the document.

An implementation is required to support writing of XML documents that use the "UTF-8" or "UTF-16" encoding. An implementation may support additional encodings.

Unmappable characters for the specified charset will be encoded as numeric character references.

The specified stream remains open after this method returns.

stringPropertyNames

open fun stringPropertyNames(): MutableSet<String!>!

Returns an unmodifiable set of keys from this property list where the key and its corresponding value are strings, including distinct keys in the default property list if a key of the same name has not already been found from the main properties list. Properties whose key or value is not of type String are omitted.

The returned set is not backed by this Properties object. Changes to this Properties object are not reflected in the returned set.

toString

open fun toString(): String

Returns a string representation of this Hashtable object in the form of a set of entries, enclosed in braces and separated by the ASCII characters " , " (comma and space). Each entry is rendered as the key, an equals sign =, and the associated element, where the toString method is used to convert the key and element to strings.

rehash

protected open fun rehash(): Unit

Increases the capacity of and internally reorganizes this hashtable, in order to accommodate and access its entries more efficiently. This method is called automatically when the number of keys in the hashtable exceeds this hashtable's capacity and load factor.

defaults

protected var defaults: Properties!

A property list that contains default values for any keys not found in this property list.

entries

open val entries: MutableSet<MutableEntry<Any!, Any!>>

Returns a Set view of the mappings contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own remove operation, or through the setValue operation on a map entry returned by the iterator) the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll and clear operations. It does not support the add or addAll operations.

keys

open val keys: MutableSet<Any!>

Returns a Set view of the keys contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own remove operation), the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll, and clear operations. It does not support the add or addAll operations.

size

open val size: Int

Returns the number of keys in this hashtable.

values

open val values: MutableCollection<Any!>

Returns a Collection view of the values contained in this map. The collection is backed by the map, so changes to the map are reflected in the collection, and vice-versa. If the map is modified while an iteration over the collection is in progress (except through the iterator's own remove operation), the results of the iteration are undefined. The collection supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Collection.remove, removeAll, retainAll and clear operations. It does not support the add or addAll operations.