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Top Description Fields Constructors Methods
net.ucanaccess.util

public final Class Sql

extends Object
implements CharSequence
Class Inheritance
All Implemented Interfaces
java.lang.CharSequence
Imports
java.util.Arrays, .Objects, java.util.stream.Collectors, .StreamSupport

An immutable sql statement string created from multiple tokens in order to write inline sql statements in an easy-to-read fashion spread out over multiple lines of code.

The class implements CharSequence and thus can be used as a drop-in alternative wherever API supports CharSequence rather than String.

Please note that the validity of the statement is never checked, and that null or empty inputs are permitted (no run-time exceptions).
The input of multiple tokens is formatted into a single String by removing leading and trailing whitespace and concatenating non-empty tokens by a single space character. Further, any trailing semicolons are removed from the resulting sql string.

Example:

    String tblName = "table";
    Sql.of("SELECT COUNT(*)",
           "FROM", tblName,
           " WHERE cond1 = :cond1",
           "   AND cond2 = :cond2");
Author
Markus Spann
Since
v5.1.0

Field Summary

Modifier and TypeField and Description
private static final Sql
EMPTY_SQL

private final String
str

The internal sql string.

Constructor Summary

AccessConstructor and Description
private
Sql(String sql)

Method Summary

Modifier and TypeMethod and Description
public char
charAt(int index)

Implements java.lang.CharSequence.charAt.

Returns the char value at the specified index.

public boolean
equals(Object obj)

Overrides java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.

pack-priv static String

Returns:

formatted sql string
format(Iterable<? extends CharSequence>
collection of tokens
tokens)

Formats an sql statement from multiple tokens.

public int
hashCode()

Overrides java.lang.Object.hashCode.

Returns a hash code value for this object.

public int
length()

Implements java.lang.CharSequence.length.

Returns the length of this character sequence.

public static Sql
of(CharSequence... tokens)

public static Sql
of(Iterable<? extends CharSequence> tokens)

public CharSequence
subSequence(int start, int end)

Implements java.lang.CharSequence.subSequence.

Returns a CharSequence that is a subsequence of this sequence.

public String
toString()

Overrides java.lang.Object.toString.

Implements java.lang.CharSequence.toString.

Returns a string containing the characters in this sequence in the same order as this sequence.

Inherited from java.lang.Object:
clonefinalizegetClassnotifynotifyAllwaitwaitwait

Field Detail

EMPTY_SQLback to summary
private static final Sql EMPTY_SQL
strback to summary
private final String str

The internal sql string. Cannot be null.

Constructor Detail

Sqlback to summary
private Sql(String sql)

Method Detail

charAtback to summary
public char charAt(int index)

Implements java.lang.CharSequence.charAt.

Doc from java.lang.CharSequence.charAt.

Returns the char value at the specified index. An index ranges from zero to length() - 1. The first char value of the sequence is at index zero, the next at index one, and so on, as for array indexing.

If the char value specified by the index is a surrogate, the surrogate value is returned.

Annotations
@Override
equalsback to summary
public boolean equals(Object obj)

Overrides java.lang.Object.equals.

Doc from java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

  • It is reflexive: for any non-null reference value x, x.equals(x) should return true.
  • It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
  • It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
  • It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
  • For any non-null reference value x, x.equals(null) should return false.

An equivalence relation partitions the elements it operates on into equivalence classes; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes.

Annotations
@Override
formatback to summary
pack-priv static String format(Iterable<? extends CharSequence> tokens)

Formats an sql statement from multiple tokens.
Leading and trailing whitespace is removed from each token and empty tokens ignored.
The tokens are joined using a single blank character to create the sql string.
Finally, any trailing semicolons are removed from the resulting sql.

Parameters
tokens:Iterable<? extends CharSequence>

collection of tokens

Returns:String

formatted sql string

hashCodeback to summary
public int hashCode()

Overrides java.lang.Object.hashCode.

Doc from java.lang.Object.hashCode.

Returns a hash code value for this object. This method is supported for the benefit of hash tables such as those provided by java.util.HashMap.

The general contract of hashCode is:

  • Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
  • If two objects are equal according to the equals method, then calling the hashCode method on each of the two objects must produce the same integer result.
  • It is not required that if two objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.
Annotations
@Override
lengthback to summary
public int length()

Implements java.lang.CharSequence.length.

Doc from java.lang.CharSequence.length.

Returns the length of this character sequence. The length is the number of 16-bit chars in the sequence.

Annotations
@Override
ofback to summary
public static Sql of(CharSequence... tokens)
ofback to summary
public static Sql of(Iterable<? extends CharSequence> tokens)
subSequenceback to summary
public CharSequence subSequence(int start, int end)

Implements java.lang.CharSequence.subSequence.

Doc from java.lang.CharSequence.subSequence.

Returns a CharSequence that is a subsequence of this sequence. The subsequence starts with the char value at the specified index and ends with the char value at index end - 1. The length (in chars) of the returned sequence is end - start, so if start == end then an empty sequence is returned.

Annotations
@Override
toStringback to summary
public String toString()

Overrides java.lang.Object.toString.

Implements java.lang.CharSequence.toString.

Doc from java.lang.CharSequence.toString.

Returns a string containing the characters in this sequence in the same order as this sequence. The length of the string will be the length of this sequence.

Annotations
@Override