Querying Feature Layer in OpenLayers 3 based on layers?

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I need to query the Feature Layer in open layer 3 based on the layers . How can i do that if i have two ,three layers on it?

this.featureLayer = new ol.layer.Vector({ source: new ol.source.Vector({ features: [featurePoint] }), style: new ol.style.Style({ image: new ol.style.Circle({ stroke: new ol.style.Stroke({ color: '#0000FF', width: 1 }), radius: 150 }) }) }); this.map.addLayer(this.featureLayer);

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