org.gcube.resources.discovery.client.queries.impl

Class QueryTemplate

java.lang.Object

org.gcube.resources.discovery.client.queries.impl.QueryBox

org.gcube.resources.discovery.client.queries.impl.QueryTemplate

All Implemented Interfaces:

Query

Direct Known Subclasses:

XQuery

public class QueryTemplate
extends QueryBox
implements Query

A Query that interpolates named parameters inside a template.

Templates are strings with empty XML elements, optionally with a DEFAULT attribute, e.g.:

all results that satisfy <cond1/> or <cond2 def='that'/> <extra/>

Whenever expression() is invoked, the elements in the template are replaced according to the first rule that applies among the following:

• by the value of an equally named parameter, if one exists
• by the value of the DEFAULT attribute, if one exists
• by the empty string

For example, given the previous template and the single parameter cond1="this", expression() returns:

all results that satisfy this or that

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT

Constructor Summary

Constructors

Constructor and Description
QueryTemplate(String template) Creates an instance with a template.
QueryTemplate(String template, Map<String,String> parameters) Creates an instance with a template and an initial set of parameters.

Method Summary

Modifier and Type	Method and Description
void	addParameter(String name, String value) Adds a parameter to the query, overwriting any value that it may already have.
void	appendParameter(String name, String value) Adds a parameter to the query, extending any value that it may already have.
String	expression() Returns the textual expression of the query.
boolean	hasParameter(String name) Returns true if the query has a given parameter.
String	parameter(String name) Returns the current value of a parameter.

Methods inherited from class org.gcube.resources.discovery.client.queries.impl.QueryBox

equals, hashCode, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

DEFAULT

public static final String DEFAULT

See Also:

Constant Field Values

Constructor Detail

QueryTemplate

public QueryTemplate(String template)

Creates an instance with a template.

Parameters:

template - the template

QueryTemplate

public QueryTemplate(String template,
                     Map<String,String> parameters)

Creates an instance with a template and an initial set of parameters.

Parameters:

template - the template

Method Detail

expression

public String expression()

Description copied from interface: Query

Returns the textual expression of the query.

Specified by:

expression in interface Query

Overrides:

expression in class QueryBox

Returns:

the expression.

addParameter

public void addParameter(String name,
                         String value)

Adds a parameter to the query, overwriting any value that it may already have.

Parameters:

name - the parameter name

value - the parameter value

Throws:

IllegalStateException - if the parameter name or value are null

appendParameter

public void appendParameter(String name,
                            String value)

Adds a parameter to the query, extending any value that it may already have.

Parameters:

name - the parameter name

value - the value

Throws:

IllegalStateException - if the parameter name or value are null

parameter

public String parameter(String name)
                 throws IllegalStateException

Returns the current value of a parameter.

Parameters:

name - the parameter name

Returns:

the value

Throws:

IllegalStateException - if the parameter does not exist

IllegalStateException - if the parameter name is null

hasParameter

public boolean hasParameter(String name)

Returns true if the query has a given parameter.

Parameters:

name - the parameter name

Returns:

true if the query has a given parameter, false otherwise

Throws:

IllegalStateException - if the parameter name is null