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

Class 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

    • 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

      • 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