Current File : //home/waritko/yacy/source/net/yacy/cora/federate/solr/logic/AbstractOperations.java
package net.yacy.cora.federate.solr.logic;
import java.util.ArrayList;
import java.util.List;
public abstract class AbstractOperations extends AbstractTerm implements Operations {
protected final String operandName;
protected final List<Term> terms;
public AbstractOperations(final String operandName) {
this.operandName = operandName;
this.terms = new ArrayList<>();
}
@Override
public int hashCode() {
int h = operandName.hashCode();
for (Term t: this.terms) h += t.hashCode();
return h;
}
/**
* Add the term with the defined logical operator.
* If length of term is empty nothing is changed
* @param term
*/
@Override
public void addOperand(Term term) {
if (!term.toString().isEmpty()) {
this.terms.add(term);
}
}
/**
* As a Operations object is a collection of Terms, we must be able to show them
* @return the list of terms
*/
@Override
public List<Term> getOperands() {
return this.terms;
}
/**
* the weight attribute of a term shows if rewritten terms
* (using rules of replacement as allowed for propositional logic)
* are shorter and therefore more efficient.
* @return the number of operators plus the number of operands plus one
*/
@Override
public int weight() {
return terms.size() * 2;
}
@Override
public boolean isBinary() {
return this.terms.size() == 2;
}
/**
* can we set brackets anywhere (means: can we change calculation order)?
*/
@Override
public boolean isAssociative() {
return true;
}
/**
* can we switch operands (must be binary)
*/
@Override
public boolean isCommutative() {
return isBinary();
}
/**
* can we 'multiply inside' (must be binary)
*/
@Override
public boolean isDistributive() {
return isBinary();
}
@Override
public Term lightestRewrite() {
return this;
}
/**
* create a Solr query string from this conjunction
* @return a string which is a Solr query string
*/
@Override
public String toString() {
if (this.terms.size() == 0) return "";
StringBuilder sb = new StringBuilder();
if (this.terms.size() == 1) {
sb.append(terms.iterator().next().toString());
} else {
sb.append('(');
for (Term term: this.terms) {
if (sb.length() > 1) sb.append(' ').append(this.operandName).append(' ');
sb.append(term.toString());
}
sb.append(')');
}
return sb.toString();
}
}
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